I have a GridView. I am using the nested ScrollViewer's SnapPoints to snap each record into view. Because this is only a visual change, and not a data change, how can I determine which record(s) is currently visible? Something like SelectedItem, but a visual query. I could check every record, but it seems inefficient. Ideas?
In your case you could use the VisualTreeHelperExtensions from WinRT XAML Toolkit and do something like this
gridView
.GetDescendantsOfType<GridViewItem>()
.Select(gvi => gridView.ItemFromContainer(gvi));
It does a somewhat intensive visual tree search, but might be OK for your scenario if your GridView uses virtualization since the items returned are in or near the view port. If you want to be more precise you can test for bounding rect intersections. Something like this might be enough:
static class RectExtensions
{
public static bool ContainsPartOf(this Rect bigRect, Rect smallRect)
{
// this is a very targeted test for horizontally scrollable smallRects inside of a bigRect
return bigRect.Left < smallRect.Left && bigRect.Right > smallRect.Left ||
bigRect.Left < smallRect.Right && bigRect.Right > smallRect.Right;
}
}
var sv = gridView.GetFirstDescendantOfType<ScrollViewer>();
var bigRect = new Rect(0, 0, sv.ActualWidth, sv.ActualHeight);
gridView
.GetDescendantsOfType<GridViewItem>()
.Where(gvi => bigRect.ContainsPartOf(gvi.GetBoundingRect(sv)))
.Select(gvi => gridView.ItemFromContainer(gvi));
Related
I'm trying to figure out a way to build a progress bar with React. I have a forEach loop that iterates through an array of about 7,000 indexes. Each time I validate a row, I want to update a state variable with percentage completion (and render this on the page live). I've tried iterating through these indexes, and updating my state variable (hoping to update the page) in the loop but I'm realizing that will not work. I obviously can't do this with a normal variable as it will reset when the component re-renders. Can anyone give me some insight on this topic?
Thanks.
Here is a code snippet from what I'm looking at:
parsedAssets.forEach(asset => {
newAssetValidated = validateBulkUpload(asset, parsedAssets, assetList, accountLogged, jobSites);
!newAssetValidated.reject_err ? validatedAssetList.accepted.push(newAssetValidated) : validatedAssetList.rejected.push(newAssetValidated);
setStateAssets({ ...stateAssets, validatedAssetList });
});
}
So essentially, as each asset is either accepted or rejected we add it to "stateAssets", and I'm hoping to build the progress bar from the length of the combined arrays that are getting set in stateAssets. However, when the forEach loop is completed, only the last validated asset is getting set due to it not updating until the forEach loop is completed.
Personally I can't imagine such a heavy validation, that you need progress-bar, but anyway.
First solution is to separate validation itself from state update for progress-bar into separate "threads". But since JS is single threaded, you may use some tricks with setTimeout or setInterval functionality. It may be very tricky, and in general not recommended practice with React.
Another way is - to set the work into queue & process 1 item at a time.
As an example I would do it something like this:
function ComponentWithProgress({parsedAssets, setParsedAssets}) {
const [validatedAssetList, setValidatedAssetList] = useState([])
const [progress, setProgress] = useState(0)
const [toDo, setToDo] = useState([])
if(parsedAssets && parsedAssets.length>0) {
setToDo(parsedAssets)
// clear parsedAssets in parent component to: [], false, null ...
// so you put it into toDo only once
setParsedAssets([])
}
if(toDo.length > 0) {
const asset = toDo[0]
const newToDo = toDo.slice(1) // All but 0th element
const newAssetValidated = validateBulkUpload(asset);
setValidatedAssetList([ ...validatedAssetList, newAssetValidated ]);
setToDo(newToDo)
setProgress( newToDo.length / ( validatedAssetList.length + newToDo.length ) * 100 )
}
// ... Render here
// If you need only accepted
const accepted = validatedAssetList.filter(v => !v.reject_err)
}
This example maybe not work for you as is, because you didn't showed us the context, but the main idea is here.
I am writing an analyzer to visually see where my application is spending time. The interface that I am trying to achieve (see below) is something similar to a tree table with
lines or boxes to denote response time.
be a collapsible tree like graph
the ability to display metrics in the table columns (e.g., start time, cost, etc)
the ability to display the labels or description and metrics on the left and lines on the right
I create the following diagram (see below) in R -- unfortunately, although the graph production is automated, the approach is not interactive. I was wondering if you could suggest a better way -- maybe a tree table. I looked at many Swing, JavaFx tree table examples. I have not seen an example that has lines (time lines) in a tree table.
Any suggestions would be greatly appreciated. Thanks in advance.
You can show any node in a TreeTableCell using the grahic property in javaFX. This includes Rectangles.
This is a simple example of showing bars in a column using Rectangles:
// Arrays in TreeItems contain {startValue, endValue} (both positive)
TreeItem<int[]> root = new TreeItem<>(new int[]{0, 10});
root.getChildren().addAll(new TreeItem<>(new int[]{0, 5}), new TreeItem<>(new int[]{5, 10}));
TreeTableView<int[]> ttv = new TreeTableView<>(root);
// Column displaying bars based on data of TreeItem. Do not use this as
// the first column, otherwise the alignment be off depending on the
// distance to the root.
TreeTableColumn<int[], int[]> column = new TreeTableColumn<>();
column.setCellValueFactory(c -> c.getValue().valueProperty());
final double BAR_SIZE = 20;
column.setCellFactory((t) -> new TreeTableCell<int[], int[]>() {
// the bar
private final Rectangle rectangle = new Rectangle(0, 10);
{
setContentDisplay(ContentDisplay.GRAPHIC_ONLY);
// bar invisible by default
rectangle.setVisible(false);
setGraphic(rectangle);
}
#Override
protected void updateItem(int[] item, boolean empty) {
super.updateItem(item, empty);
if (!empty && item != null) {
// resize and display bar, it item is present
rectangle.setWidth((item[1] - item[0]) * BAR_SIZE);
rectangle.setTranslateX(item[0] * BAR_SIZE);
rectangle.setVisible(true);
} else {
// no item -> hide bar
rectangle.setVisible(false);
}
}
});
// add a columns new column
// add a additional empty column at the start to prevent bars being
// aligned based on distance to the root
ttv.getColumns().addAll(new TreeTableColumn<>(), column);
Things you need to do
use a data type different to int[]; the cell value factory and TreeTableCell needs to be adjusted accordingly; an example of a more complex model can be found e.g. in the oracle tutorial: https://docs.oracle.com/javase/8/javafx/user-interface-tutorial/tree-table-view.htm
Choose better colors; These colors could e.g. be stored in a Map and created if a new one is needed.
add additional colums
I have this foreach function, but I need to add a where clause.
I have added a checkboxlist in Umbraco called "show"
Values if this is
"EN"
"SP"
"US"
...
Let us say I have checked EN and SP.
I only want a slide to be visible if the slide is Visible as now, and if the field show are "EN" is checked and true. How can i add this in my code?
#foreach (var Slider in Umbraco.ContentSingleAtXPath("//HomePage/SliderArea").Children.Where("Visible").OrderBy("CreateDate
desc").Take(4))
The code you have is using Dynamics and therefore you're restricted to using the pseudo-Linq extensions like .Where("Visible"). You'll find it much easier to manipulate the list of items if you use the Typed objects instead.
Change this:
// Returns IPublishedContent as dynamic
Umbraco.ContentSingleAtXPath("//HomePage/SliderArea")
to this:
// Returns fully typed IPublishedContent
Umbraco.TypedContentSingleAtXPath("//HomePage/SliderArea")
Then you'll be able to use the full power of Linq to do this:
var area = Umbraco.TypedContentSingleAtXPath("//HomePage/SliderArea");
// returns a filtered IEnumerable<IPublishedContent>
var sliders = area.Children.Where(c => c.IsVisible() && c.GetPropertyValue<string>("show") == "EN");
#foreach (IPublishedContent slider in sliders.OrderByDescending(c => c.CreateDate).Take(4))
{
// You can get the dynamic equivalent of the IPublishedContent like this if you wish:
dynamic dSlider = slider.AsDynamic();
// ...
}
I've spent nearly 1 week to learn working with objects instead of arrays. I had thought it was easy to call them and created some objects and set their properties. However I can't access them now, I tried this:
function onBoxClick(event:MouseEvent):void {
var str:String = event.currentTarget.name;
trace(str);
str = str.substring(str.indexOf("_") + 1);
trace(getChildByName("copy_" + str)); // trying to trace an object by name
}
My question is if there's a practical way of dealing with objects, otherwise what's the purpose of using them.
Edit: Here's my function that I use to create movieclips and other things:
function addBoxes(isUpdate:Boolean):void {
var copyOne:Object = getReadOnlyValues();
copyOne.name = "copy_" + num;
// Set default mc1 settings
var settings1:Object = copyOne.mc1Settings;
for(var num2:String in settings1) {
copyOne.mc1[num2] = settings1[num2];
}
// Set default mc1text settings
var settings2:Object = copyOne.mc1TextSettings;
for(var num3:String in settings2) {
copyOne.mc1Text[num3] = settings2[num3];
}
copyOne.mc1.x = nextXpos;
copyOne.mc1.name = "captionBox_" + num;
addChild(copyOne.mc1);
copyOne.mc1.addEventListener(MouseEvent.CLICK, onCaptionClick);
copyOne.mc1Text.name = "captionBoxText_" + num;
copyOne.mc1.addChild(copyOne.mc1Text);
// ---------------------------------------------------------------
// Set default mc2 settings
var settings4:Object = copyOne.mc2Settings;
for(var num4:String in settings4) {
copyOne.mc2[num4] = settings4[num4];
}
// Set default mc2text settings
var settings5:Object = copyOne.mc2TextSettings;
for(var num5:String in settings5) {
copyOne.mc2Text[num5] = settings5[num5];
}
copyOne.mc2.x = nextXpos;
copyOne.mc2.y = copyOne.mc1.height;
copyOne.mc2.name = "box2_" + num;
addChild(copyOne.mc2);
copyOne.mc2Text.name = "box2BoxText_" + num;
copyOne.mc2.addChild(copyOne.mc2Text);
copyOne.mc2.addEventListener(MouseEvent.CLICK, onBoxClick);
if (num / subunits is int) {
trace (num);
// createMc("normalBox", true);
}
nextXpos = nextXpos + copyOne.mc2.width;
// traceObj(copyOne);
// traceObj(getReadOnlyValues());
}
I called this function in a loop so I created many movieclips. Now I can't access objects' properties and their childen (e.g textfield).
Objects I have on stage: Movieclips and textfields
Where they come from: The function above
What I'm trying to do with them: Tracing movieclips and textfields (that are holded by objects) to change their children (textfield) text
What happens instead of what I expect: Trace code outputs undefined instead of giving me object type trace(getChildByName("copy_" + str)); // trying to trace an object by name
Is there a practical way of accessing an object whose name is "copy_1" and its property whose name is "box2_1" (movieclip)?
One problem I see is the "copyOne" object has been created within the scope of "addBoxes", so it will no longer exist outside of this function.
Another is you're trying to access an Object via getChildByName, which only addresses displayObjects of the displayObjectContainer you are calling from.
If you want to loosely keep track of variables with things like Objects or MovieClips (which are both dynamic-style objects that let you add properties to them as you wish), just use MovieClips to house your values. The movieClips, being on the stage, will be retained in memory until removed from the displayList (stage).
Also, check out the Dictionary, a sort of key/value based way of storing collections of objects.
Better yet, if you use strongly-typed custom objects (creating your own classes to extend MCs, and adding your own public or private methods and values), there are benefits such as using Vectors (fancy, fast arrays that are compatible with any Object type you choose).
I don't really know if I understood your question or not, but as #ozmachine said in his answer, you can not use getChildByName, instead I think that you can take a look on this, may be it can help :
var container:DisplayObjectContainer = this;
function getReadOnlyValues():Object {
return {
mc1: new box(),
mc1: {
name: 'mc1_',
alpha: 1,
x: 0,
y: 0,
width: 30,
height: 25
},
mc1Text: new TextField(),
mc1Text: {
text: 'test',
x: 0,
y: 0,
selectable: false,
multiline: false,
wordWrap: false
}
}
};
// create 5 objects
for(var i=0; i<5; i++){
container['copy_'+i] = getReadOnlyValues();
var obj:Object = getObjectByName('copy_'+i);
obj.mc1.alpha = 1;
obj.mc1.x = 0;
obj.mc1.y = 50 * i;
obj.mc1.width = 100;
obj.mc1.addChild(obj.mc1Text);
obj.mc1Text.text = 'test_' + i;
addChild(obj.mc1);
}
// get object by name
function getObjectByName(name:String):Object {
return container[name];
}
// change the text of the 4th button
stage.addEventListener(MouseEvent.CLICK, function(e:MouseEvent):void {
var obj:Object = getObjectByName('copy_3');
obj.mc1Text.text = 'new text';
})
Array and Object are both data structures.
Data means some form of information.
Data structure means some form of information being stored in a certain way.
Array and Object are two different ways to store information.
Arrays identify data with integer numbers.
An integer number to identify a single element of an array is called an index
Arrays are ideal to represent a list of similar things that belong to each other.
var names:Array = ["John", "Paul", "George", "Ringo"];
This often means that the elements of an array are of the same type, like in the example above.
But they don't have to:
var numbers:Array = [42, "twenty-five", "XIIV"];
For the above examples it's easy to answer the questions "What are the names of the four beatles?", "What different representations of numbers did you stumble upon during your trip through the historic town?". Other questions are harder or impossible to answer. "What Roman numerals did you stumble upon in the historic town?"
Objects identify data with names.
A name to identify a single element of an object is called a property
Objects are ideal to represent a list of dissimilar things that belong to each other.
var paula:Object = {age:37, name:"Paula", hairColor:0x123456};
This often means that the elements of an object are of different type, like in the example above.
But they don't have to:
var car:Object = {manufacturer:"Porsche", color:"red", sound:"wroooooom", soundOfDriver:"weeeeeeeeeeee"};
Considering this, let's take a look at your code and see how it applies.
The big picture is that you have a function addBoxes that you call multiple times. As one function should have one purpose, this function will do something similar every time it is executed. Uh-Oh: "similar". Whatever the result of this function is, it should go into an array. Each call to that function would be an element of the array. You can see this clearly on your use of "num" to identify whatever is happening in your current run of the function.
What data is present in your function?
copyOne
mc1
mc1Text
mc2
mc2Text
copyOne is a troublemaker here and what causes your confusion. It's trying to do everything at once and therefore you are not able to think clearly about when to use a Array and when Object. One would call it a god object. And that's not a good object to have around.
Your choice for variable names is very bad.
You choose super generic names like "mcX" only to later add a name property to it that describes what it truly is.
But even that doesn't hold true for whatever "Box2" is supposed to be.
Choose names so that it'S easy to understand what something in your code is.
It looks like you created all or parts of this structure jsut for this question and therefore lacked meaningful names.
I highly recommend that you do not learn by such made up projects. But from the real world.
I will therefore impose the following goal:
mc1 and mc1Text represent a caption
mc2 and mc2Text represent a content
With all this, I ask again:
What data is present in your function?
captionBox
captionText
contentBox
contentText
Both caption and content consist of a box and a text.
These are different things, so caption and content are each an object with properties "box" and "text"
One could think that due to this similarity, they both should go into an array.
But I beg to differ. A caption and a text are not the same thing. You deal with captions and texts differently. Walking on the streets you might catch a big caption in the news quickly, but not a lengthy text. That's why each of them should be a property of the object that's created in the function.
Here's somewhat of a conclusion:
var allBoxes:Array = []; // array to store the similar results of every function call
function createBoxes():void
{
var boxes:Object = {};
//the box consists of caption & content, both bying of the same type, but are containing different data
boxes.caption = {box:{}, text:{}}; //caption
boxes.content = {box:{}, text:{}}; //content
allBoxes.push(boxes);
}
This is it. That's how and why I would model your data with objects and arrays.
But it doesn't end here. My conclusion lacks a lot of the code you posted.
While the above is mostly language independent, the missing code is specific to Actionscript and not just on how to model data. It's as follows...
As3 is object oriented.
This is good, because the above conclusion has a lot of objects in it.
To define how some object is/does/moves/farts/etc, one creates classes.
The following changes take place (for reasons out of the scope of this answer):
createBoxes (formerly known as addBoxes) calls the constructor of
a class "CaptionAndContent" that extends Sprite.
There's no more need to explicitely create an object "boxes" as the constructor does exactly that.
The caption and content will not have a property "box", because
they can be the box themselves. This is exactly how it's done in the
code of the question. The default settings are set in the constructors of their classes.
Here's reduced snippet of code that hopefully illustrates how the classes could look like.
Each class should be in its own file, with the necessary imports, package block and the additional functionality that you did not specify in your question.
public class CaptionAndContent extends Sprite
{
private var caption:Caption;
private var content:Content;
public function CaptionAndContent(captionText:String = "", contentText:String = "")
{
caption = new Caption(captionText);
addChild(caption);
content = new Content(contentText);
content.y = caption.height;
addChild(content);
}
}
public class ClickableBoxWithText extends Sprite
{
protected var textField:TextField;
public function ClickableBoxWithText(text:String = "")
{
textField = new TextField();
textField.text = text;
addChild(textField);
addEventListener(MouseEvent.CLICK, onClick);
}
protected function onClick(mouseEvent:MouseEvent):void
{
//override this in a sublclass
}
}
public class Caption extends ClickableBoxWithText
{
public function Caption(text:String = "")
{
super(text);
// apply all the default settings of caption here.
}
}
public class Content extends ClickableBoxWithText
{
public function Content(text:String = "")
{
super(text);
// apply all the default settings of content here.
}
}
Using them would look something like this:
var allBoxes:Array = []; // array to store the similar results of every function call
function createBoxes():void
{
var captionAndContent:CaptionAndContent = new CaptionAndContent("This is the caption...", "...for this content");
captionAndContent.x = nextXpos;
addChild(captionAndContent);
allBoxes.push(captionAndContent);
}
Last but not least, the identification problem in the click handler.
Your question already contains the answer:
event.currentTarget
That's the reference to the object that was clicked on.
In my code it would be
mouseEvent.currentTarget
This identifies the object already. It's pointless to look up one of its properties (its name for example) in order to search all the objects for that name, just to identify the same object that you already had to identify (without a name) in order to get the name.
You aren't identifying the objects by name anyway. What differs between the names and what supposedly makes them unique is a number at their end. As pointed out in this answer, this is what's called an index and the thing you are trying to identify with it should go into an array. In my example codes, this is allBoxes.
i have a class (TheList.as). in which i have an array "Data" and it has a couple of values. Then i have a loop through which i am creating a scrollable list which uses the values from "Data" array. [I am trying make a unit converter]
Then i have another class "Units.as". In that class i have created three instances of "TheList". A main list ("myList"), and to sublists "ListFrom" and "ListTo". They are using values from "Data" array. Now i have text field whose value changes to whatever item is clicked. When i click "Angle" in the main list, i want the sublists to get populated with ("Degree", "Radian" etc)..
Here is what i tried
if(myList._TextLabel.text == "Angle")
{
ListFrom.Data = ["Degree", "Radian"];
}
But nothing happens, i do not get any error either. When i do this in an "ENTER_FRAME" event and trace (ListFrom.Data), i can see that the values change, but they do not get assigned to the list items in the list. I would really appreciate the help. Thanks!
Here are complete Classes for understanding the situation better(the code is pretty messy, as i am a newbie to OOP)
TheList.as: http://pastebin.com/FLy5QV9i
Units.as : http://pastebin.com/z2CcHZzC
where you call ListFrom.Data = ["Degree","Radian"], make sure when the data changed, the renders in the ListFrom have been set new data. for example, you may use MyRender in ListFrom for show, you should debug in the set data method in MyRender.
you should call the code below after you call ListFrom.Data = ["Degree","Radian"];
for (var i:int = 0; i < Data.legnth;i++) {
var render:MyRender = ListFrom[i] as MyRender;
if (render) {
render.data = Data[i];
} else {
var render:MyRender = new MyRender();
render.data = Data[i];
ListFrom.addChild(render);
}
}
You can use event listeners, singleton classes or reference one class to another, depending on the style you want. All are equally valid and fast / efficient.