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Android how to detect "delete" button press on keyboard to delete a single character?

I'm working on a remote control app and need to detect when a user pressed the <x delete button on an empty text field to send this character over and delete something from a remote machine.
How can I detect that the user pressed <x Delete button on Android keyboard?
I tried to ad on key listener, but that did not seem to work.
final EditText edittext = (EditText) findViewById(R.id.editText);
edittext.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
// If the event is a key-down event on the "enter" button
Log.i("KEYCODE", "" + keyCode);
if ((event.getAction() == KeyEvent.ACTION_DOWN) &&
(keyCode == KeyEvent.KEYCODE_ENTER)) {
// Perform action on key press
return false;
} else if (edittext.length() == 0) {
if(keyCode == KeyEvent.KEYCODE_DEL) {
//perform erase when the text field is empty
}
}
return false;
}
});

I know I am late, but hope this will help someone else.
There is no direct way to do this using a listener, but if you look into the documentation of onTextChanged Listener you will find this:
This method is called to notify you that, within s, the count characters beginning at start have just replaced old text that had length before.
So in case of a backspace you will have this condition:
Within s(the editable view), 0 characters beginning at start(depends where the cursor is) have replaced old text that had length before(it's value will be generally 1, unless user first selected some text and then hit backspace)
So if count == 0 you can assume that delete key was pressed.

Use the method DispatchKeyEvent :
#Override public boolean dispatchKeyEvent(#NonNull KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN
&& event.getKeyCode() == KeyEvent.KEYCODE_DEL) {
// ...
}
return super.dispatchKeyEvent(event);
}
(stolen from here)

You can't use a View.OnKeyListener for software keyboards.
View.OnKeyListener:
Interface definition for a callback to be invoked when a hardware key event is dispatched to this view. This is only useful for hardware keyboards; a software input method has no obligation to trigger this listener.
Source: http://developer.android.com/reference/android/view/View.OnKeyListener.html

LWJGL: detecting left/right clicks when getButtonCount returns 0

On the Dell Inspiron 15 3000, the touchpad doesn't have any physical left/right buttons. Instead, it is one giant touchpad that is pressure sensitive. I'm assuming it detects right/left clicks based off of hand position on the trackpad.
In my LWJGL application, I detect mouse button clicks with Mouse.isButtonDown(0). This works fine on computers with a mouse with physical buttons, but doesn't work on touchpads that lack physical buttons. Mouse.getButtonCount() returns 0.
Has anybody had any success in detecting if a mouse button is pressed, should the user be using a trackpad that doesn't have physical buttons?

I think, instead of using
org.lwjgl.input.Mouse
This class could be what you are searching for:
org.lwjgl.input.Controllers
http://legacy.lwjgl.org/javadoc/org/lwjgl/input/Controllers.html
Im not entirely sure though since I only have a mouse and no way to test this with a touchpad.

For those who find this in the future, I did find a fix:
You cannot, should there be no physical buttons, use the Mouse.isButtonDown() method. Instead, you are going to have to read the event buffer. To do so, I wrote my own helper class:
public class Mouse{
private static boolean button_left = false, button_right = false;
public static boolean isButtonDown(int button){
if(button == 0) return button_left;
if(button == 1) return button_right;
return false;
}
public static void update(){
while(org.lwjgl.input.Mouse.next()){
if(org.lwjgl.input.Mouse.getEventButton() == 0) button_left = org.lwjgl.input.Mouse.getEventButtonState();
if(org.lwjgl.input.Mouse.getEventButton() == 1) button_right = org.lwjgl.input.Mouse.getEventButtonState();
}
}
}
The update() method is called every tick, and as such I can get button states using Mouse.isButtonDown(button).

Getting current fingers position on Android

I'm developing an application that needs to get all fingers on the screen of the Android. That's not complex, and I could make it in a few lines of code.
However, the way android sends callbacks is not what I need. I have done many tests, and here is what I could find out:
Once he sent the fingers positions, if no "big" movement has been made, he will not send a onTouch event.
Also, when a finger is REMOVED from the screen (for example: there are 3 fingers, and one is removed), it seems that it ONLY sends the next event, if at least one of the remaining fingers move on the screen.
I'm doing some tracking on fingers, and matching with objects, and to do this properly, I need to know all the fingers positions all the time. If there is not a way to "request" finger's touch event even when it didn't moved, how can I access the current finger positions without an callback event? Is there any other solution?
Here is my code:
ArrayList<Vector3> fingerTips = new ArrayList<Vector3>();
#Override
public boolean onTouchEvent(MotionEvent event) {
final int points = event.getPointerCount();
String out = "==========\n";
fingerTips.clear();
for(int i = 0; i < points; i++){
out += "\tPoint "+i+"\t("+event.getX(i)+", "+event.getY(i) + ")\n";
fingerTips.add( new Vector3(event.getX(i), event.getY(i)) );
}
Log.i(TAG, out);
// Send touches to SurfaceView
chwaziViewGL.onUpdateFingerTips(fingerTips);
return true;
}

My problem was that I didn't received one event with all the finger positions AFTER removing a finger...
After lot's of tests and logging, I discovered that it's true (in part).
Whenever you REMOVE a finger on the SCREEN, the NEXT event sent is an ACTION_POINTER_UP or ACTION_UP, meaning that the finger x is no longer touching the screen.
Since there was NO motion after removing the finger, the last MotionEvent sent was the UP, containg the removed finger also.
So, to fix that, I check if the action is UP, and on the loop that get's all the fingers, I created an if checking if that was the finger removed from the screen. If so, I just didn't add it to the array.
Here is my final code:
ArrayList<Vector3> fingerTips = new ArrayList<Vector3>();
#Override
public boolean onTouchEvent(MotionEvent event) {
final int points = event.getPointerCount();
// Check if it's an event that a finger
// was removed, if so, set removedPoint
int removedPoint = -1;
final int action = event.getAction() & MotionEvent.ACTION_MASK;
if(action == MotionEvent.ACTION_POINTER_UP || action == MotionEvent.ACTION_UP)
removedPoint = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
>> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
String out = "==========\n";
fingerTips.clear();
for(int i = 0; i < points; i++){
// Find out pointer ID
int pointerID = event.getPointerId(i);
if(pointerID == MotionEvent.INVALID_POINTER_ID){
out += "\tPoint "+pointerID+" INVALID\n";
continue;
}
// Check if it's the removed finger
if(removedPoint == i){
out += "\tPoint "+pointerID+" REMOVED\n";
continue;
}
out += "\tPoint "+pointerID+"\t("+event.getX(i)+", "+event.getY(i) + ")\n";
fingerTips.add( new Vector3(event.getX(i), event.getY(i), pointerID) );
}
Log.i(TAG, out);
// Send touches to SurfaceView
chwaziViewGL.onUpdateFingerTips(fingerTips);
return true;
}

Sorry, but your code cost me a lot of hairs;-(( After days I found the problem finally before I got insane. This code
final int action = event.getAction() & MotionEvent.ACTION_MASK;
if(action == MotionEvent.ACTION_POINTER_UP || action == MotionEvent.ACTION_UP)
removedPoint = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
>> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
could have never been worked!!!
Why? Because if you mask the value that is coming from getAction() it is simply a plain integer value of the action. And when you try to use this plain value and masking it again with something, it has no meaning at all!
The correction is to use again event.getAction() in the seconds masking:
removedPoint = (event.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK)
>> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
It was really a nightmare to find this. But anyway, I think you just wanted the best and help others:-))) Its ok.

selecting textViews and getting their values

I am trying to accomplish following things
Suppose I have 5-6 TextViews with values S N A K E
Now, I want to press S textView then slide my finger over N to select it too and then move my way to E. I want to do that so that i can get "SNAKE" in my string or char sequence etc
If there is any idea do share me. I can't get it how to use onTouch here.
Also, i am adding textViews dynamically so i am setting their ids dynamically too
Best Regards

I've never done this, but here's a thought.
Assuming all your textviews are in some sort of layout, you could disable the focusability on your textview and create an onTouch listener on your underlying container.
Start tracking on Mouse Down events
#Override public boolean onTouch(View v, MotionEvent event) {
if(event.getAction == MotionEvent.ACTION_DOWN)
{
captureInput = true;
}
}
*On your ACTION_MOVE event, check if the current position is above a textview, if so, capture that value*
#Override public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
if(action == MotionEvent.ACTION_DOWN)
{
captureInput = true;
}
else if(action == MotionEvent.ACTION_MOVE
{
//get x/y of your finger
int X = (int)event.getX();
int Y = (int)event.getY();
//Somehow check if the x,y are overlapping with one of your textivews
// If so, add that textview's text to your list
// Below is pseudo code
/* for(TextView curTV: allTextViews)
{
if(isOverlapping(X,Y))
{
listOfSwipedCharacters.add(curTV.getText());
}
}
}
}
Lastly, when the user releases their finger, stop tracking and do something with the word list
#Override public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
if(action == MotionEvent.ACTION_DOWN)
{
captureInput = true;
}
else if(action == MotionEvent.ACTION_MOVE
{
//get x/y of your finger
int X = (int)event.getX();
int Y = (int)event.getY();
//Somehow check which textview the X,Y coords are overlapping
// Below is pseudo code
/* for(TextView curTV: allTextViews)
{
if(isOverlapping(X,Y))
{
listOfSwipedCharacters += (curTV.getText());
}
}*/
}
else if(action == MotionEvent.ACTION_UP)
{
captureInput = false;
//Do whatever you want with the string of information that you've captured
}
}
Once again, I have no idea if that will work, it's just a guess at an approach. I suspect performance of cycling through each textview to check for overlaps will be pretty crappy, so there may be a more efficient approach than running a for loop.
Since you know you can't jump over letters when swyping, you could create a short list of all the possible swipe locations (surrounding letters) whenever you add a new letter. Then on your mouse event, check if any of those letters have been hit by the mouse move event. For example, in a standard word search game, once you select a letter, there are only 9 other possible locations for you to swipe (the surrounding letters), so you should only bother checking if those 9 locations have been hit when you capture the mouse move event.
Edit: I suppose you could use the solution above if you attached an onTouch listener to each and every textview. The same premise in regards to touch would apply: Down = start capture, move = capture text, up = stop capture. It would save you from having to identify which textview is being hovered as the textview that fires the onTouch event will be the one that the user is swiping across.

Slide finger into buttons android

How can I make it possible that when someone slides their finger into or over a button, the button acts as if it were getting pushed?
An example of what i'm looking for would be a keyboard app. Where you slide your fingers over all the keys to play sounds.

You can use an OnTouchListener like this:
boolean firstTime = true;
OnTouchListener testTouchListener = new OnTouchListener(){
public boolean onTouch(View v, MotionEvent me){
Rect r = new Rect();
secondButton.getDrawingRect(r);
if(r.contains((int)me.getX(),(int)me.getY())){
//Log.i(myTag, "Moved to button 2");
if(firstTime == true){
firstTime = false;
secondButton.performClick();
}
}
if(me.getAction() == MotionEvent.ACTION_UP){
//When we lift finger reset the firstTime flag
firstTime = true;
}
return false;
}
};
firstButton.setOnTouchListener(testTouchListener);
With this approach though you are going to get a flood of touch events because onTouch() gets called a lot with MotionEvent.ACTION_MOVE. So you'll have to keep a boolean that tells you if its the first time you've gotten onTouch() call. Then you can reset that boolean in onTouch() for MotionEvent.ACTION_UP so it works again the next time. However this could get kind of complicated if you are trying to do more than just 2 buttons. I think you'd have to keep a boolean for each of them seperately (or perhaps an array of booleans to hold them all). and you'd need an additional if(r.contains(x,y) statements for every button. This should get you started on the right path though.