I am trying to create a signed apk for my application but i get an error after clicking finish after the create a signed apk dialogue.
Error:Error: This class should provide a default constructor (a public constructor with no arguments) (MYAPPNAME.CustomListAdapter) [Instantiatable]
Java code below
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class CustomListAdapter extends ArrayAdapter {
private final Activity context;
private final String[] itemname;
private final Integer[] imgid;
public CustomListAdapter(Activity context, String[] itemname, Integer[] imgid) {
super(context, R.layout.mylist, itemname);
// TODO Auto-generated constructor stub
this.context=context;
this.itemname=itemname;
this.imgid=imgid;
}
public View getView(int position,View view,ViewGroup parent) {
LayoutInflater inflater=context.getLayoutInflater();
View rowView=inflater.inflate(R.layout.mylist, null,true);
TextView txtTitle = (TextView) rowView.findViewById(R.id.item);
ImageView imageView = (ImageView) rowView.findViewById(R.id.icon);
//TextView extratxt = (TextView) rowView.findViewById(R.id.textView1);
txtTitle.setText(itemname[position]);
imageView.setImageResource(imgid[position]);
// extratxt.setText("Description "+itemname[position]);
return rowView;
};
Help Please
The issue was solved in the build.gradle file. Inside the android string add the following:
lintOptions {
abortOnError false
}
Related
I am trying to serialise and deserialise a class RuleMessage but can't get it to work. Here is my code:
public class RuleMessage {
private String id;
private SerializableRunnable sRunnable;
public RuleMessage(String id, SerializableRunnable sRunnable) {
this.id = id;
this.sRunnable = sRunnable;
}
}
public interface SerializableRunnable extends Runnable, Serializable {
}
#Test
public void testSerialization() throws JsonProcessingException {
MAPPER.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL,
JsonTypeInfo.As.PROPERTY);
SerializableRunnable r = () -> System.out.println("Serializable!");
RuleMessage rule = new RuleMessage("1", r);
System.out.println(MAPPER.writeValueAsString(businessRule));
}
I am using Java 8. Can someone tell me if this is possible in the Jackson library?
Jackson was created to keep object state not behaviour. This is why it tries to serialise POJO's properties using getters, setters, etc. Serialising lambdas break this idea. Theres is no any property to serialise, only a method which should be invoked. Serialising raw lambda object is really bad idea and you should redesign your app to avoid uses cases like this.
In your case SerializableRunnable interface extends java.io.Serializable which gives one option - Java Serialisation. Using java.io.ObjectOutputStream we can serialise lambda object to byte array and serialise it in JSON payload using Base64 encoding. Jackson supports this scenario providing writeBinary and getBinaryValue methods.
Simple example could look like below:
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class JsonLambdaApp {
public static void main(String[] args) throws IOException {
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
SerializableRunnable action = () -> System.out.println("Serializable!");
String json = mapper.writeValueAsString(new RuleMessage("1", action));
System.out.println(json);
RuleMessage ruleMessage = mapper.readValue(json, RuleMessage.class);
ruleMessage.getsRunnable().run();
}
}
#JsonSerialize(using = LambdaJsonSerializer.class)
#JsonDeserialize(using = LambdaJsonDeserializer.class)
interface SerializableRunnable extends Runnable, Serializable {
}
class LambdaJsonSerializer extends JsonSerializer<SerializableRunnable> {
#Override
public void serialize(SerializableRunnable value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ObjectOutputStream outputStream = new ObjectOutputStream(byteArrayOutputStream)) {
outputStream.writeObject(value);
gen.writeBinary(byteArrayOutputStream.toByteArray());
}
}
}
class LambdaJsonDeserializer extends JsonDeserializer<SerializableRunnable> {
#Override
public SerializableRunnable deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
byte[] value = p.getBinaryValue();
try (ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(value);
ObjectInputStream inputStream = new ObjectInputStream(byteArrayInputStream)) {
return (SerializableRunnable) inputStream.readObject();
} catch (ClassNotFoundException e) {
throw new IOException(e);
}
}
}
class RuleMessage {
private String id;
private SerializableRunnable sRunnable;
#JsonCreator
public RuleMessage(#JsonProperty("id") String id, #JsonProperty("sRunnable") SerializableRunnable sRunnable) {
this.id = id;
this.sRunnable = sRunnable;
}
public String getId() {
return id;
}
public SerializableRunnable getsRunnable() {
return sRunnable;
}
}
Above code prints JSON:
{
"id" : "1",
"sRunnable" : "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"
}
and lambda:
Serializable!
See also:
How to serialize a lambda?
How to serialize a lambda function in Java?
First, in RuleMessage you have to either create getters / setters or make the fields public in order to provide Jackson access to the fields.
Your code then prints something like this:
{"#class":"RuleMessage","id":"1","sRunnable":{"#class":"RuleMessage$$Lambda$20/0x0000000800b91c40"}}
This JSON document cannot be deserialized because RuleMessage has no default constructor and the lambda cannot be constructed.
Instead of the lambda, you could create a class:
public class Runner implements SerializableRunnable {
#Override
public void run() {
System.out.println("Serializable!");
}
}
and construct your pojo like this:
new RuleMessage("1", new Runner())
The Jackson deserializer is now able to reconstruct the objects and execute the runner.
I am working with kafka and spring boot and I need to send JSON object to kafka, the point is that I am able to send an object as JSON configuring KafkaTemplate but just for this object.
package com.bankia.apimanager.config;
import com.bankia.apimanager.model.RequestDTO;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.StringSerializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;
import org.springframework.kafka.support.serializer.JsonSerializer;
import java.util.HashMap;
import java.util.Map;
#Configuration
public class KafkaConfiguration {
#Value("${spring.kafka.bootstrap-servers}")
private String bootstrapServers;
#Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);
return props;
}
#Bean
public ProducerFactory<String, RequestDTO> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
#Bean
public KafkaTemplate<String, RequestDTO> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
}
package com.bankia.apimanager.controller;
import com.bankia.apimanager.model.RequestDTO;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.SendResult;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.util.concurrent.ListenableFutureCallback;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
#RestController
#RequestMapping("/infrastructure")
public class InfraStructureRequestController {
private final static Logger LOG = LoggerFactory.getLogger( InfraStructureRequestController.class );
private static final String TOPIC = "test";
#Autowired
private KafkaTemplate<String, RequestDTO> sender;
#RequestMapping(value = "/test", method = RequestMethod.GET)
public String postMessage(){
ListenableFuture<SendResult<String, RequestDTO>> future = sender.send(TOPIC, new RequestDTO("Hola","Paco"));
future.addCallback(new ListenableFutureCallback<SendResult<String, RequestDTO>>() {
#Override
public void onSuccess(SendResult<String, RequestDTO> result) {
LOG.info("Sent message with offset=[" + result.getRecordMetadata().offset() + "]");
}
#Override
public void onFailure(Throwable ex) {
LOG.error("Unable to send message due to : " + ex.getMessage());
}
});
return "OK";
}
}
but what about if now I want to send a new DTO object? do I have to declare a new KafkaTemplate<String,NEWOBJECT> and autowire each kafka template declared in configuration for each object? there is another way to be able to just declare one kafkaTemplate in which I can send any type of object and automatically will be serialized in JSON?
I think, you can specify a generic KafkaTemplate<String, Object> and set the producer value serializer to JsonSerializer like this:
#Configuration
public class KafkaConfiguration {
#Value("${spring.kafka.bootstrap-servers}")
private String bootstrapServers;
#Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);
return props;
}
#Bean
public ProducerFactory<String, Object> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
#Bean
public KafkaTemplate<String, Object> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
}
Referring your code:
Value Serializer is correctly defined as JsonSerializer, which will convert objects of any type to JSON.
#Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);
return props;
}
Change <String, RequestDTO> to <String, Object> at every place in KafkaConfig & Controller.
Keep in mind that generics remain until compile time (type erasure)
only.
There are two scenario:
Scenario #1
If you want to use KafkaTemplate to send any type(as mentioned in your question) to kafka, so there is no need to declare your own KafkaTemplate bean because Spring boot did this for you in KafkaAutoConfiguration.
package org.springframework.boot.autoconfigure.kafka;
...
#Configuration(proxyBeanMethods = false)
#ConditionalOnClass(KafkaTemplate.class)
#EnableConfigurationProperties(KafkaProperties.class)
#Import({ KafkaAnnotationDrivenConfiguration.class, KafkaStreamsAnnotationDrivenConfiguration.class })
public class KafkaAutoConfiguration {
private final KafkaProperties properties;
public KafkaAutoConfiguration(KafkaProperties properties) {
this.properties = properties;
}
#Bean
#ConditionalOnMissingBean(KafkaTemplate.class)
public KafkaTemplate<?, ?> kafkaTemplate(ProducerFactory<Object, Object> kafkaProducerFactory,
ProducerListener<Object, Object> kafkaProducerListener,
ObjectProvider<RecordMessageConverter> messageConverter) {
KafkaTemplate<Object, Object> kafkaTemplate = new KafkaTemplate<>(kafkaProducerFactory);
messageConverter.ifUnique(kafkaTemplate::setMessageConverter);
kafkaTemplate.setProducerListener(kafkaProducerListener);
kafkaTemplate.setDefaultTopic(this.properties.getTemplate().getDefaultTopic());
return kafkaTemplate;
}
}
**Some Note**:
This config class has been annotated with #ConditionalOnClass(KafkaTemplate.class) that means: (from spring docs--->) #Conditional that only matches when the specified classes are on the classpath.
kafkaTemplate bean method is annotated with
#ConditionalOnMissingBean(KafkaTemplate.class) that means: (from spring docs ---->) #Conditional that only matches when no beans meeting the specified requirements are already contained in the BeanFactory.
Important! In pure java world, KafkaTemplate<?, ?> is not subtype of for example: KafkaTemplate<String, RequestDTO> so you can't to do this:
KafkaTemplate<?, ?> kf1 = ...;
KafkaTemplate<String, RequestDTO> kf2 = kf1; // Compile time error
because java parameterized types are invariant as mentioned in Effective Java third edition item 31. But is spring world that is ok and will be injected to your own service. You need only to specify your own generic type on your kafkaTemplate properties.
For example:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Service;
#Service
public class KafkaService {
#Autowired
private KafkaTemplate<Integer, String> kafkaTemplate1;
#Autowired
private KafkaTemplate<Integer, RequestDTO> KafkaTemplate2;
}
Scenario #2
If you need to restrict value type of kafka record then you need to specify your own kafka bean something like this:
#Configuration(proxyBeanMethods = false)
#ConditionalOnClass(KafkaTemplate.class)
#EnableConfigurationProperties(CorridorTracingConfiguration.class)
public class CorridorKafkaAutoConfiguration {
#Bean
#ConditionalOnMissingBean(KafkaTemplate.class)
public KafkaTemplate<?, AbstractMessage> kafkaTemplate(ProducerFactory<Object, AbstractMessage> kafkaProducerFactory,
ProducerListener<Object, AbstractMessage> kafkaProducerListener,
ObjectProvider<RecordMessageConverter> messageConverter) {
KafkaTemplate<Object, AbstractMessage> kafkaTemplate = new KafkaTemplate<>(kafkaProducerFactory);
messageConverter.ifUnique(kafkaTemplate::setMessageConverter);
kafkaTemplate.setProducerListener(kafkaProducerListener);
kafkaTemplate.setDefaultTopic(this.properties.getTemplate().getDefaultTopic());
return kafkaTemplate;
}
Now this can be injected only to
KafkaTemplate<String, AbstractMessage> kafkaTemplate, the key type can be anything else instead of String. But you can send any sub type of AbstractMessage to kafka via it.
An example usage:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Service;
#Service
public class KafkaService {
#Autowired
private KafkaTemplate<String, AbstractMessage> kafkaTemplate;
public void makeTrx(TrxRequest trxRequest) {
kafkaTemplate.send("fraud-request", trxRequest.fromAccountNumber(), new FraudRequest(trxRequest));
}
}
#Accessors(chain = true)
#Getter
#Setter
#EqualsAndHashCode(callSuper = true)
#ToString(callSuper = true)
public class FraudRequest extends AbstractMessage {
private float amount;
private String fromAccountNumber;
private String toAccountNumber;
...
}
To restrict the key of kafka message follow the same (above) way
So i using retrofit2 to fetch my json into my main activity it runs smoothly, but im using bottom navigation so i should convert my code from activity into fragment.
my code didnt show error after i debug it, it shows force close when the fragment opened
This is my Fragment Code:
package com.itsalex.helios.fragment;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.MenuItemCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.itsalex.helios.Adapter;
import com.itsalex.helios.ApiClient;
import com.itsalex.helios.ApiInterface;
import com.itsalex.helios.Contact;
import com.itsalex.helios.R;
import com.itsalex.helios.activity.CartActivity;
import com.itsalex.helios.activity.ProdukActivity;
import com.itsalex.helios.adapters.HorizontalAdapter;
import com.itsalex.helios.adapters.VerticalAdapter;
import com.itsalex.helios.model.Food;
import com.itsalex.helios.model.GeneralFood;
import com.itsalex.helios.recycleFragment;
import com.itsalex.helios.rest.RetrofitClient;
import com.itsalex.helios.rest.RetrofitInterface;
import java.util.ArrayList;
import java.util.List;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
public class StatusFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public StatusFragment() {
// Required empty public constructor
}
/*private appController mController;*/
public List<Contact> contacts;
public Adapter adapter;
private RecyclerView recyclerView;
protected Handler handler;
private ApiInterface apiInterface;
ProgressBar progressBar;
TextView search;
String[] item;
private Call<ResponseBody> result;
public static recycleFragment newInstance(String param1, String param2) {
recycleFragment fragment = new recycleFragment();
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v;
v = inflater.inflate(R.layout.fragment_recycle, container, false);
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
progressBar = v.findViewById(R.id.prograss);
recyclerView = v.findViewById(R.id.frg_recyclerView);
handler = new Handler();
contacts = new ArrayList<>();
recyclerView.setHasFixedSize(true);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(mLayoutManager);
//adapter = new Adapter(getContext(), contacts, recyclerView, recyclerView, false);
adapter = new Adapter(contacts, getContext());
recyclerView.setAdapter(adapter);
fetchContact("users", "");
return v;
}
public void fetchContact(String type, String key){
apiInterface = ApiClient.getApiClient().create(ApiInterface.class);
Call<List<Contact>> call = apiInterface.getContact(type, key);
call.enqueue(new Callback<List<Contact>>() {
#Override
public void onResponse(Call<List<Contact>> call, Response<List<Contact>> response) {
progressBar.setVisibility(View.GONE);
contacts = response.body();
adapter = new Adapter(contacts, getContext());
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
#Override
public void onFailure(Call<List<Contact>> call, Throwable t) {
progressBar.setVisibility(View.GONE);
Toast.makeText(getContext(), "Error\n"+t.toString(), Toast.LENGTH_LONG).show();
}
});
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
/*if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}*/
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
this is my adapter activity
package com.itsalex.helios;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
public class Adapter extends RecyclerView.Adapter<Adapter.MyViewHolder> {
private List<Contact> contacts;
private Context context;
public Adapter(List<Contact> contacts, Context context) {
this.contacts = contacts;
this.context = context;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);
return new MyViewHolder(view);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.name.setText(contacts.get(position).getName());
holder.email.setText(contacts.get(position).getEmail());
}
#Override
public int getItemCount() {
return contacts.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder{
TextView name,email;
public MyViewHolder(View itemView) {
super(itemView);
name = itemView.findViewById(R.id.name);
email = itemView.findViewById(R.id.email);
}
}
}
In the Logcat it shows error
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at com.itsalex.helios.Adapter.getItemCount(Adapter.java:40)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3722)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3527)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4082)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1077)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:132)
at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1361)
at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:894)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1702)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1556)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1465)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1702)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1556)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1465)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2483)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2185)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1314)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7057)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:829)
at android.view.Choreographer.doCallbacks(Choreographer.java:606)
at android.view.Choreographer.doFrame(Choreographer.java:576)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:815)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6934)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
i google it and i didnt find the answer, what should i do?
Thanks in advance
You have not initialised your progress bar.Use findViewById to set progressbar to your required progressbar.
SimpleA.java class is target class. I have to mock getList method of SimpleB.java class if add method is non-static its working fine but it is showing problem with static add method
SimpleA.java
import java.util.ArrayList;
public class SimpleA {
private static SimpleB obj1 ;
public static int add(){
ArrayList<Integer> arr1 = obj1.getList1();
ArrayList<Integer> arr2 = obj1.getList2();
int res=0;
for(Integer val : arr1){
res+=val;
}
for(Integer val1 : arr2){
res+=val1;
}
return res;
}
}
SimpleB.java
import java.util.ArrayList;
import java.util.Iterator;
public class SimpleB {
public ArrayList<Integer> getList1(){
System.out.println("inside class SimpleB and getlist1");
ArrayList<Integer> lst1 = new ArrayList<Integer>();
lst1.add(10);
lst1.add(20);
return lst1;
}
public ArrayList<Integer> getList2(){
System.out.println("inside class SimpleB and getlist2");
ArrayList<Integer> lst2 = new ArrayList<Integer>();
lst2.add(30);
lst2.add(40);
return lst2;
}
}
SimpleATest.java
This is test class here I am testing for SimpleA.java class
import java.lang.reflect.Field;
import java.util.ArrayList;
import org.easymock.EasyMock;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.PowerMock;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.powermock.reflect.Whitebox;
#RunWith(PowerMockRunner.class)
#PrepareForTest({SimpleA.class})
public class SimpleATest {
SimpleA simpleA1;
SimpleB mockSample;
#Before
public void setUp(){
ArrayList<Integer> lst = new ArrayList<Integer>();
lst.add(30);
lst.add(40);
lst.add(100);
simpleA1 = new SimpleA();
mockSample = PowerMock.createMock(SimpleB.class);
PowerMock.mockStatic(SimpleA.class);
EasyMock.expect(mockSample.getList1()).andReturn(lst);
EasyMock.expect(mockSample.getList2()).andReturn(lst);
PowerMock.replay(mockSample);
Whitebox.setInternalState(simpleA1,mockSample);
System.out.println("Init method is invoked");
}
#Test
public void testAdd(){
int res = simpleA1.add();
System.out.println("res = "+res);
}
#After
public void destroy(){
System.out.println("Destroy method is invoked");
}
}
I have seen this behavior in the past. The way around is to set first the default answer on the static methods and then fill in the behavior as such:
#RunWith(PowerMockRunner.class)
#PrepareForTest(MyClassWithStaticMethods.class)
public testClass{
#Test
public void testSomething(){
// this prepares the class; all static methods get a default return value (in this case type Object is returned and the default returned object is null)
PowerMockito.mockStatic(MyClassWithStaticMethods.class, new Answer<Object>()
{
#Override
public Object answer(InvocationOnMock invocation) throws Throwable {
return null;
}
});
//Now the class is prepared, we can just change the behaviour of the static method in the way we would like.
String in = "example input string";
String out = "example output string";
// after preparing the class, you can override a specific static method. For this example we use the matchers, could also have used Matchers.any(String.class) or any other matcher combination as long as it maps on the method.
PowerMockito.when(MyClassWithStaticMethods.staticMethod(Matchers.eq(in))).thenReturn(out);
}
//..body
}
I have problem with persisting polish PL-pl locale characters in mysql db.
I know that is common issue, and out there in the internet is many solution to this. But I cant figure it out. I think I've tried everything.
All my web page correctly encode and display UTF-8 characters (static from html and from db)
Problem cames when I save somthing in db using form on my application. So I think it is tightly related to JDBC, JPA and hibernate.
Here is my configuration:
application.properties
#DB Properties:
# Mysql
db.driver=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost:3300/derp?characterEncoding=UTF-8
hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
db.username=root
db.password=motorolaa835
# H2
#db.driver=org.h2.Driver
#db.url=jdbc:h2:~/sts/derp/db/derp_db
#hibernate.dialect=org.hibernate.dialect.H2Dialect
#db.username=root
#Hibernate Configuration:
hibernate.show_sql=true
hibernate.hbm2ddl.auto=update
#hibernate.hbm2ddl.auto=create
hibernate.connection.CharSet=utf8
hibernate.connection.characterEncoding=utf8
hibernate.connection.useUnicode=true
services.entitymanager.packages.to.scan=com.derp
cms.entitymanager.packages.to.scan=com.derp.cms.model
common.entitymanager.packages.to.scan=com.derp.common.model
procedure.entitymanager.packages.to.scan=com.derp.procedure.model
Initializer
package com.derp.common.init;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration.Dynamic;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.filter.HiddenHttpMethodFilter;
import org.springframework.web.servlet.DispatcherServlet;
public class Initializer implements WebApplicationInitializer {
#Override
public void onStartup(ServletContext servletContext) throws ServletException {
AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
ctx.register(WebAppConfig.class);
ctx.register(ThymeleafConfig.class);
servletContext.addListener(new ContextLoaderListener(ctx));
ctx.setServletContext(servletContext);
Dynamic servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(ctx));
servlet.addMapping("/");
servlet.setAsyncSupported(true);
servlet.setLoadOnStartup(1);
// Allow to use Put and Delete method for REST architecture
registerCharachterEncodingFilter(servletContext);
registerHiddenFieldFilter(servletContext);
}
private void registerCharachterEncodingFilter(ServletContext aContext) {
CharacterEncodingFilter cef = new CharacterEncodingFilter();
cef.setForceEncoding(true);
cef.setEncoding("UTF-8");
aContext.addFilter("charachterEncodingFilter", cef).addMappingForUrlPatterns(null ,true, "/*");
}
private void registerHiddenFieldFilter(ServletContext aContext) {
aContext.addFilter("hiddenHttpMethodFilter", new HiddenHttpMethodFilter()).addMappingForUrlPatterns(null ,true, "/*");
}
}
WebAppConfig
package com.derp.common.init;
import java.util.Properties;
import javax.annotation.Resource;
import javax.sql.DataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.http.MediaType;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.hibernate4.HibernateTransactionManager;
import org.springframework.orm.hibernate4.LocalSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
//import com.derp.common.wicketView.HomePage;
#Configuration
#ComponentScan("com.derp")
#EnableWebMvc
#EnableTransactionManagement
#PropertySource("classpath:application.properties")
public class WebAppConfig extends WebMvcConfigurerAdapter {
private static final String PROPERTY_NAME_DATABASE_DRIVER = "db.driver";
private static final String PROPERTY_NAME_DATABASE_PASSWORD = "db.password";
private static final String PROPERTY_NAME_DATABASE_URL = "db.url";
private static final String PROPERTY_NAME_DATABASE_USERNAME = "db.username";
private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
private static final String PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO = "hibernate.hbm2ddl.auto";
private static final String PROPERTY_NAME_HIBERNATE_CONNECTION_CHARSET = "hibernate.connection.CharSet";
private static final String PROPERTY_NAME_HIBERNATE_CONNECTION_CHARACTERENCODING = "hibernate.connection.characterEncoding";
private static final String PROPERTY_NAME_HIBERNATE_CONNECTION_USEUNICODE = "hibernate.connection.useUnicode";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_SERVICES = "services.entitymanager.packages.to.scan";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_COMMON = "common.entitymanager.packages.to.scan";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_CMS = "cms.entitymanager.packages.to.scan";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_PROCEDURE = "procedure.entitymanager.packages.to.scan";
#Resource
private Environment env;
#Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(env.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));
dataSource.setUrl(env.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));
dataSource.setUsername(env.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));
dataSource.setPassword(env.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));
return dataSource;
}
#Bean
public LocalSessionFactoryBean sessionFactory() {
LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean();
sessionFactoryBean.setDataSource(dataSource());
//sessionFactoryBean.setPackagesToScan(env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
sessionFactoryBean.setPackagesToScan(new String[] {
env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_SERVICES),
env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_COMMON),
env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_CMS),
env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN_PROCEDURE)
});
sessionFactoryBean.setHibernateProperties(hibProperties());
return sessionFactoryBean;
}
private Properties hibProperties() {
Properties properties = new Properties();
properties.put(PROPERTY_NAME_HIBERNATE_DIALECT, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));
properties.put(PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO));
properties.put(PROPERTY_NAME_HIBERNATE_CONNECTION_CHARSET, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_CONNECTION_CHARSET));
properties.put(PROPERTY_NAME_HIBERNATE_CONNECTION_CHARACTERENCODING, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_CONNECTION_CHARACTERENCODING));
properties.put(PROPERTY_NAME_HIBERNATE_CONNECTION_USEUNICODE, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_CONNECTION_USEUNICODE));
properties.put("jadira.usertype.autoRegisterUserTypes", "true");
return properties;
}
#Bean
public HibernateTransactionManager transactionManager() {
HibernateTransactionManager transactionManager = new HibernateTransactionManager();
transactionManager.setSessionFactory(sessionFactory().getObject());
return transactionManager;
}
#Override
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
// Simple strategy: only path extension is taken into account
configurer.favorPathExtension(true).
ignoreAcceptHeader(true).
useJaf(false).
defaultContentType(MediaType.TEXT_HTML).
mediaType("html", MediaType.TEXT_HTML).
mediaType("xml", MediaType.APPLICATION_XML).
mediaType("json", MediaType.APPLICATION_JSON);
}
#Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/img/**").addResourceLocations("/WEB-INF/img/*");
registry.addResourceHandler("/css/**").addResourceLocations("/WEB-INF/css/*");
registry.addResourceHandler("/js/**").addResourceLocations("/WEB-INF/js/*");
registry.addResourceHandler("/lib/**").addResourceLocations("/WEB-INF/lib/*");
}
}
ThymeleafConfig
package com.derp.common.init;
import nz.net.ultraq.thymeleaf.LayoutDialect;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.thymeleaf.spring4.view.ThymeleafViewResolver;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;
#Configuration
public class ThymeleafConfig {
#Bean
public ServletContextTemplateResolver templateResolver() {
ServletContextTemplateResolver resolver = new ServletContextTemplateResolver();
resolver.setPrefix("/WEB-INF/view/");
resolver.setSuffix(".html");
resolver.setTemplateMode("HTML5");
resolver.setOrder(1);
resolver.setCacheable(false);
return resolver;
}
#Bean
public SpringTemplateEngine templateEngine() {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.setTemplateResolver(templateResolver());
templateEngine.addDialect(new LayoutDialect());
//templateEngine.addDialect(new SpringStandardDialect());
return templateEngine;
}
#Bean
public ThymeleafViewResolver thymeleafViewResolver() {
ThymeleafViewResolver resolver = new ThymeleafViewResolver();
resolver.setTemplateEngine(templateEngine());
resolver.setCharacterEncoding("UTF-8");
return resolver;
}
}
Edit
There is no utf-8 characters when using this method on controller
controller
#RequestMapping(value="/test", method=RequestMethod.PUT)
#ResponseBody
public String ajaxTest() {
return "Characters test: ęółąśżźćń";
}
and the javasscript ajax method
$(document).ready(function() {
$('h1').click(function() {
$.ajax({
type: "PUT",
url: "/derp/procedury/test",
data: "none",
success: function (response, status, xhr) {
showNotifications(status, xhr.responseText);
},
error: function (response, status, xhr) {
showNotifications('error', JSON.stringify(response));
showNotifications('error', status);
showNotifications('error', xhr);
}
});
});
The result I get is:
Characters test: ?�???????
Please give some helpful suggestions. Thanks in advance.
I had the same problem, I've added the following filter config to my MyServletInitializer
and there's no more problem (in my case other configs don't work):
public class MyServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
....
#Override
protected Filter[] getServletFilters() {
CharacterEncodingFilter filter = new CharacterEncodingFilter();
filter.setEncoding("UTF-8");
filter.setForceEncoding(true);
return new Filter[]{filter};
}
....
}
Working solution:
Code to add in initializer class:
private void registerCharachterEncodingFilter(ServletContext aContext) {
CharacterEncodingFilter cef = new CharacterEncodingFilter();
cef.setForceEncoding(true);
cef.setEncoding("UTF-8");
aContext.addFilter("charachterEncodingFilter", cef).addMappingForUrlPatterns(null ,true, "/*");
}
and then call it in initializer in
onStartup method
with ServletContext:
registerCharachterEncodingFilter