Hy everyone,
I'm trying to do some calculations in a JTable after iteration and mark with different background the cells that I need.
However, I have 2 problems at the moment:
1) Cells are not painted immediately, but after the whole iteration cycle
2) Areas are not painted properly - if I need to paint table[3, 4] and table[6, 5] it draws a rectangular from [3,4] up to [6, 5] instead of drawing the singular cells only.
About problem 1: could I call repaint() with priority without the need to finish everything and the JVM to decide whenever to paint? I try to do fireTableCellUpdated() and fireTableDataChanged() but they don't get updated.
Here there is my custom cell renderer method that changes the BGcolor:
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row,int column) {
Component renderer = super.getTableCellRendererComponent(
table, value, isSelected, hasFocus, row, column);
if(value instanceof Color) {
Color c = (Color) value;
renderer.setBackground(c);
System.out.println("BG change [" + row + ":" + column + "]");
}
return renderer;
}
Here there is the loop where I paint my cells on a button click:
for(int paintJ = startIndex; paintJ < endIndex; paintJ++) {
CrossCellRenderer rend = (CrossCellRenderer) jTable1.getCellRenderer(i, paintJ)
.getTableCellRendererComponent(jTable1, Color.blue, true, true, i, paintJ);
crossTableModel.fireTableCellUpdated(i, paintJ);
jTable1.revalidate();
jTable1.repaint();
try {
Thread.sleep(1000);
} catch(InterruptedException ie) {
System.err.println("Exception sleeping the thread.");
}
}
Any tips on that?
Hate to say: but you do it (whatever you want to reach) completely wrong ;-)
Never-ever do any direct manipulation/paint on a renderer, instead change the model data and the rest will happen automatically.
Never-ever call any of the fireXX methods on a model from outside the model, it's the exclusive responsibility of the model to notify
its listeners on change
Never-ever (or very very rarely, certainly not here ;-) there's a need to call revalidate and/or repaint dircectly, will happen
automatically if a model is well-behaved
....
Best to read Snoracle's tutorial on howto-use tables to fully understand the rendering mechanism
http://download.oracle.com/javase/tutorial/uiswing/components/table.html
Roughly:
// change the model, will notify its listeners
model.setValueAt(....)
// in a custom renderer, check the value and decorate as appropriate
public Component getTableCellRendererComponent(....) {
// ... normal config, f.i. done in super
Component comp = super.get...
if (myConditionForSpecialColor(table, value, ...) {
comp.setBackground(myColor);
} else {
comp.setBackground(normalColor);
}
}
// register the custom renderer
// per class
table.setDefaultRenderer(Object.class, myRenderer)
// or per column
table.getColumnModel().getColumn(myColumn).setCellRenderer(myRenderer)
Related
Unfortunately, I do not feel confident with my understanding of default constructors.
I have searched extensively to find a resource that provides an explanation to adhere to my personal learning curve of the Java language. However, upon completing an assignment, I feel I may not be meeting the assignment criteria due to my own feeling of redundancy to need for a default constructor. This is why i feel like i am misinterpreting the concept of different types of constructors all together.
I have created two constructors as the assignment requires. One that takes in no parameters and initializes instance variables to a default value. And another that takes in parameters to give values to the object variables when the new object is created in the main method.
Why am I creating a default constructor for the object if the default is never used in the main method? Below is a sample of my code:
public class Circle {
private double x; // declaring variable to hold value of x coordinate
private double y; // Variable to hold value of y coordinate
private double r; // Variable to hold value of the radius of a circle
/* default constructor */
Circle() {
x = 0.0;
y = 0.0;
r = 0.0;
}
/* constructor takes in three parameters and sets values for variables x, y, and r */
public Circle(double x, double y, double r) {
this.x = x;
this.y = y;
this.r = r;
}
// test class created for main method
public class TestCircle {
public static void main (String[] args){
Circle c1 = new Circle(2.0,3.0,9.0);
System.out.println();
System.out.println(" A circle object has been created with the following attributes:");
c1.printAttributes();
System.out.println();
System.out.println("The circle is tested for the maximum radius of 8.0...");
c1.setRadius(8.0);
System.out.println();
System.out.println("... since the radius is more than the allowable maximum, the new attributes for the Circle are:");
c1.printAttributes();
System.out.println();
System.out.println("The area of the Circle is " + c1.area());
System.out.println("The Circumference of the circle is " + c1.circumference());
System.out.println();
System.out.println("The origin of the circle is now moved by a specified amount...");
c1.move(6,-7);
System.out.println();
System.out.println("The new attributes of the circle are:");
c1.printAttributes();
System.out.println();
System.out.println("Testing if the point (10,-20) is inside the circle...");
System.out.println();
if (c1.isInside(10,-20)){
System.out.println("The point (10,-20) is inside the circle");
}
else {
System.out.println("The point (10,-20) is not inside the circle");
}
} // end of main
} // end of class
If you don’t use it you should delete it. Sometimes you will need to create empty objects in order to set attributes a posteriori, but if you are not using it at all there is no point to have it
The point of making default constructors is sometimes for back end stuff and is considered a "good programming practice" no you don't use the default constructor here in your main and in fact your code would run just fine with no default constructor comment it out and re run your tester you will see it works fine.
Recently, I am using the plugin "hole filling" of OpenFlipper, and have entirely compiled the OpenFlipper. However, the new mesh has a large number of duplicate vertices, when I tried to add the filling patch to the original mesh. I used the following codes to perform the adding operation:
// filling_patch: newly created filling mesh
// mesh_ori: the original mesh before hole filling
class MeshT::FaceHandle fh;
class MeshT::FaceIter f_it, f_end;
class MeshT::FaceVertexIter fv_it;
for(f_it = filling_patch->faces_begin(), f_end = fill_patch ->faces_end(); f_it != f_end; f_it++)
{
// ith face
fh = *f_it;
// Check whether it is valid
if(!fh.is_valid())
{
return;
}
// Store its three vertices
std::vector<class MeshT::VertexHandle> face_vhandles;
face_vhandles.clear();
// Iterate each vertex of this face
for(fv_it = mesh_ori->fv_iter(fh); fv_it.is_valid(); fv_it++)
{
// Get the 3D point
class MeshT::Point p = filling_patch->point(*fv_it);
// Add this point to original mesh. Note: vh is a new vertevHandle, differ to *fv_it
class MeshT::VertexHandle vh = mesh_ori->add_vertex(p);
face_vhandles.push_back(vh);
}
// Save the face to mesh
mesh_ori->add_face(face_vhandles);
}
So, I am not sure whether there is an existing function that can be used to fix this problem in OpenMesh.
Does someone give me some advice?
Thanks a lot.
I have a 2.5D game (2D game that acts like a 3D game) where you constantly switch depths, where the player displays on top of an object when it walks in front of it and when it walks behind it, the object displays on top of the player. Like when the player's y is less than the object's y, the player would be going behind the object and vice versa.
I tried to use a code like this:
if (player.y < block.y)
{
setChildIndex(block, numChildren - 5);
}
else if (player.y > block.y)
{
setChildIndex(block, numChildren - 10);
}
However, I see if I do it this way with multiple times, I would need tons of codes and the display list would get mixed up and sort the wrong depths in the wrong orders. Would anyone please show an organized depth changer with minimal code?
Use a z-index stack sorting, (also refered as z-buffer in the 3D graphics literature) the same used to create the 3D depth effect using just 2D techniques.
In other words assign to each object a zIndex and at regular intervals (e.g onEnterFrame event) run a zsort routine which sorts (the order of) display objects based on their zIndex value. Or, alternatively, you can run zsort routine manualy each time a change of zIndex happens on objects.
Then in your code you simply assign zIndex values to display objects to simulate an object passing in-front or behind another object and zsort takes care of the rest.
A trick here is to have appropriate gaps (i.e not necessarily next zIndex+1) in the values of zIndex assigned on objects, so that objects can be placed between these gaps to simulate passing in front or behind other objects, without having to adjust more than one zIndex value each time, i.e you adjust only one zIndex value of the object passing in-front or behind another object, and not the zIndex of that other object.
The amount of gap between successive zIndexes can be estimated from the maximum number of (other) objects which at any given time might be between these objects (so for example, if, at maximum, 3 objects might at some time move between, in-front or behind any given object, then a gap value for successive zIndexes would be 3 so that all the objects can be accomodated)
here is a very simple zsorter routine which runs periodicaly onEnterFrame event and does the necessary depth sorting for you (from reference 1. below)
package {
import flash.display.*;
import flash.events.*;
public class DepthSortSpace extends MovieClip {
public function DepthSortSpace() {
super();
this.addEventListener( Event.ADDED_TO_STAGE, this.addedToStage, false, 0, true );
}
private function addedToStage( e:Event ) {
this.stage.addEventListener( Event.ENTER_FRAME, this.enterFrame, false, 0, true );
}
private function sortDisplayList():void {
var len:uint = numChildren;
var i,j;
for( i=0; i < len-1; i++ )
for (j=i+1; j < len; j++)
if ( getChildAt(i).y > getChildAt(j).y ) this.swapChildrenAt( i, j );
}
private function enterFrame(e:Event) {
this.sortDisplayList();
}
}
}
The zsorter above is in-fact a movieClip which acts as a scene container, in that you add your display objects to the zsorter movieClip and this takes care to sort them accordingly, but one can just take the zsort routine and apply it to any DisplayObjectContainer or Scene object instance.
Note, the zsorter above uses a bubbleSort sorting algorithm, which has a O(n^2) complexity, but one can use another sorting algorithm (e.g mergeSort with O(n lgn) complexity)
examples and references
http://nephilim.blogspot.gr/2010/06/easy-depth-sorting-in-actionscript-3.html
http://www.actionscript.org/forums/actionscript-3-0-a/169035-sorting-technique.html
http://www.simppa.fi/blog/the-fastest-way-to-z-sort-and-handle-objects-in-as3/
I'd like to be able to pass Vectors around as references. Now, if a method takes a Vector.<Object>, then passing a Vector.<TRecord>, where TRecord inherits directly from Object does not work. Where a method takes just plain Object; say vec: Object, then passing the Vector is possible. Once inside this method, an explicit cast at some stage is required to access vec as a Vector again. Unfortunately, a cast seems to make a copy, which means wrapping one up in multiple Flex ListCollectionViews is useless; each ListCollectionView will be pointing to a different Vector.
Using Arrays with ArrayCollection presents no such problem, but I lose out out the type safety, neatness (code should be clean enough to eat off of) and performance advantages of Vector.
Is there a way to cast them or pass them as references in a generic manner without copies being made along the way?
Note in this example, IRecord is an interface with {r/w id: int & name: String} properties, but it could be a class, say TRecord { id: int; name: String} or any other usable type.
protected function check(srcVec: Object): void
{
if (!srcVec) {
trace("srcVec is null!");
return;
}
// srcVec = (#b347e21)
trace(srcVec.length); // 4, as expected
var refVec: Vector.<Object> = Vector.<Object>(srcVec);
// refVec = (#bc781f1)
trace(refVec.length); // 4, ok, but refVec has a different address than srcVec
refVec.pop();
trace(refVec.length); // 3 ok
trace(srcVec.length); // 4 - A copy was clearly created!!!
}
protected function test(): void
{
var vt1: Vector.<IRecord> = new Vector.<IRecord>; // (#b347e21) - original Vector address
var vt2: Vector.<Object> = Vector.<Object>(vt1); // (#bbb57c1) - wrong
var vt3: Vector.<Object> = vt1 as Vector.<Object>; // (#null) - failure to cast
var vt4: Object = vt1; // (#b347e21) - good
for (var ix: int = 0; ix < 4; ix++)
vt1.push(new TRecord);
if (vt1) trace(vt1.length); // 4, as expected
if (vt2) trace(vt2.length); // 0
if (vt3) trace(vt3.length); // vt3 is null
if (vt4) trace(vt4.length); // 4
if (vt1) trace(Vector.<Object>(vt1).length); //
trace("calling check(vt1)");
check(vt1);
}
This is not possible. If a type T is covariant with type U, then any container of T is not covariant with a container of type U. C# and Java did this with the built-in array types, and their designers wish they could go back and cut it out.
Consider, if this code was legal
var vt1: Vector.<IRecord> = new Vector.<IRecord>;
var vt3: Vector.<Object> = vt1 as Vector.<Object>;
Now we have a Vector.<Object>. But wait- if we have a container of Objects, then surely we can stick an Object in it- right?
vt3.push(new Object());
But wait- because it's actually an instance of Vector.<IRecord>, you can't do this, even though the contract of Vector.<Object> clearly says that you can insert Object. That's why this behaviour is explicitly not allowable.
Edit: Of course, your framework may allow for it to become a non-mutable reference to such, which is safe. But I have little experience with ActionScript and cannot verify that it actually does.
I have a JSlider with 65536 different values. It works great for coarse adjustments and for very fine adjustments (+/-1 using up/down arrow) but is very poor in the middle.
Is there anything out there that would be better? I can vaguely imagine taking 2 sliders one for coarse + fine adjustments, but can't really figure out how to get them to work together.
What about using a JSpinner instead of a JSlider? With a SpinnerNumberModel, you can set the step size and even change the step size dynamically.
If you're OK with having multiple controls, you could even have two spinners, one for setting your values and another for setting the step size that is used by the first spinner.
For an example of this, I took the SliderDemo code from the Swing slider tutorial and modified it instead to use two JSpinners instead of a single JSlider. Here's the most interesting part of the code that I changed:
//Create the slider^H^H^H^H^H^H spinners.
// JSlider framesPerSecond = new JSlider(JSlider.HORIZONTAL,
// FPS_MIN, FPS_MAX, FPS_INIT);
final int initStep = 1;
final SpinnerNumberModel animationModel = new SpinnerNumberModel(FPS_INIT,
FPS_MIN,
FPS_MAX,
initStep);
final SpinnerNumberModel stepSizeModel = new SpinnerNumberModel(initStep,
1,
10,
1);
final JSpinner framesSpinner = new JSpinner(animationModel);
framesSpinner.addChangeListener(this);
final JSpinner stepSpinner = new JSpinner(stepSizeModel);
stepSpinner.addChangeListener(new ChangeListener()
{
public void stateChanged(ChangeEvent arg0)
{
animationModel.setStepSize(stepSizeModel.getNumber());
}
});
I also had to make a bunch of less interesting changes, such as creating a label for the step size spinner, adding the new label and new spinner to the container, and changing the stateChanged() method on this to cast the source of the event to a JSpinner instead of casting it to a JSlider.
You could, of course, elaborate on this further, such as increasing the step size for the step size spinner (for example, so that you can change the step size from 1 to 101 in a single click). You could also use a different control instead of a JSpinner to set the step size, such as a combo box.
Finally, to make this all really easy to use, you would likely want to hook up some keystroke accelerators (possibly through a menu?) so that you could change the step size without actually moving the mouse or the keyboard focus from one spinner to another.
Edit: Given that you have to use a JSlider no matter what, are you aware that you can use PgUp/PgDn to move up and down by 1/10th of the total range?
If you want to change that 1/10th amount (such as making it dynamic), then you'll need to override the the method BasicSliderUI.scrollByBlock().
Here's an example where I just overrode the UI class of a JSlider to step by 1/4th of the range, instead of 1/10th:
//Create the slider.
JSlider framesPerSecond = new JSlider(JSlider.HORIZONTAL,
FPS_MIN, FPS_MAX, FPS_INIT);
framesPerSecond.setUI(new javax.swing.plaf.metal.MetalSliderUI() {
private static final int SLIDER_FRACTION = 4;
/**
* This code is cut, paste, and modified from
* {#link javax.swing.plaf.basic.BasicSliderUI#scrollByBlock(int).
* I should be ashamed of cutting and pasting, but whoever hardcoded the magic
* number "10" in the original code should be more ashamed than me. ;-)
*
* #param direction
* either +1 or -1
*/
#Override
public void scrollByBlock(final int direction) {
synchronized(slider) {
int oldValue = slider.getValue();
int blockIncrement = (slider.getMaximum() - slider.getMinimum()) / SLIDER_FRACTION;
if (blockIncrement <= 0 && slider.getMaximum() > slider.getMinimum()) {
blockIncrement = 1;
}
int delta = blockIncrement * ((direction > 0) ? POSITIVE_SCROLL : NEGATIVE_SCROLL);
slider.setValue(oldValue + delta);
}
}
});
From here, it wouldn't be too hard to replace that constant SLIDER_FRACTION with a variable that was set by another slider or by a spinner, would it?