My class extends View and I need to get continuous touch events on it.
If I use:
public boolean onTouchEvent(MotionEvent me) {
if(me.getAction()==MotionEvent.ACTION_DOWN) {
myAction();
}
return true;
}
... the touch event is captured once.
What if I need to get continuous touches without moving the finger?
Please, tell me I don't need to use threads or timers. My app is already too much heavy.
Thanks.
Use if(me.getAction() == MotionEvent.ACTION_MOVE). It's impossible to keep a finger 100% completely still on the screen so Action_Move will get called every time the finger moves, even if it's only a pixel or two.
You could also listen for me.getAction() == MotionEvent.ACTION_UP - until that happens, the user must still have their finger on the screen.
You need to set this properties for the element
android:focusable="true"
android:clickable="true"
if not, just produce the down action.
Her is the simple code snippet which shows that how you can handle the continues touch event. When you touch the device and hold the touch and move your finder, the Touch Move action performed.
#Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
if(isTsunami){
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// Write your code to perform an action on down
break;
case MotionEvent.ACTION_MOVE:
// Write your code to perform an action on contineus touch move
break;
case MotionEvent.ACTION_UP:
// Write your code to perform an action on touch up
break;
}
}
return true;
}
Try this. It works to me:
public static OnTouchListener loadContainerOnTouchListener() {
OnTouchListener listener = new OnTouchListener(){
#Override
public boolean onTouch(View v, MotionEvent event) {
LinearLayout layout = (LinearLayout)v;
for(int i =0; i< layout.getChildCount(); i++)
{
View view = layout.getChildAt(i);
Rect outRect = new Rect(view.getLeft(), view.getTop(), view.getRight(), view.getBottom());
if(outRect.contains((int)event.getX(), (int)event.getY()))
{
Log.d(this.getClass().getName(), String.format("Over view.id[%d]", view.getId()));
}
}
}
Remember: the listener you´ll set must be a container layout (Grid, Relative, Linear).
LinearLayout layout = findViewById(R.id.yourlayoutid);
layout.setOnTouchListener(HelperClass.loadContainerOnTouchListener());
This might help,
requestDisallowInterceptTouchEvent(true);
on the parent view, like this -
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
view.getParent().requestDisallowInterceptTouchEvent(true);
switch(motionEvent.getAction()){
}
return false;
}
I was making a game with a custom view used as a thumb control. . . here is what I did
float x = 0, y = 0;
#Override
public boolean onTouchEvent(MotionEvent event) {
x = event.getX();
y = event.getY();
// handle touch events with
switch( event.getActionMasked() ) {
case MotionEvent.ACTION_DOWN :
if(cont)
{
// remove any previous callbacks
removeCallbacks(contin);
// post new runnable
postDelayed(contin, 10);
}
invalidate();
return true;
case MotionEvent.ACTION_MOVE :
if(!cont && thumbing != null)
{
// do non-continuous operations here
}
invalidate();
return true;
case MotionEvent.ACTION_UP :
// set runnable condition to false
x = 0;
// remove the callbacks to the thread
removeCallbacks(contin);
invalidate();
return true;
default :
return super.onTouchEvent(event);
}
}
public boolean cont = false;
// sets input to continuous
public void set_continuous(boolean b) { cont = b; }
public Runnable contin = new Runnable()
{
#Override
public void run() {
if(x != 0)
{
// do continuous operations here
postDelayed(this, 10);
}
}
};
A quick note however, make sure in your main activity that is calling this view removes the callbacks manually via the onPause method as follows
#Override
protected void onPause() {
if(left.cont) left.removeCallbacks(left.contin);
if(right.cont) right.removeCallbacks(left.contin);
super.onPause();
}
That way if you pause and come back touch events aren't being handled twice and the view is free from it's thread's overhead.
** tested on Samsung Galaxy S3 with hardware acceleration on **
All these answer are partially correct but they do not resolve in the right way the problem.
First of all, for everyone out there that decide to track when the event is ACTION_MOVE. Well that works only guess when? When user move his finger, so could if you decide to implement a custom thumb control is okay but for a normal custom button that's not the case.
Second, using a flag inside ACTION_DOWN and check it in ACTION_UP seems the logic way to do it, but as Clusterfux find out if you implement a while(!up_flag) logic you get stuck into troubles ;)
So the proper way to do it is mentioned here:
Continuous "Action_DOWN" in Android
Just keep in mind that if the logic you're going to write during the continuous press has to modify the UI in some way, you have to do it from the main thread in all the other cases it's better use another thread.
You can use the below code snippet as a reference in which I used the background to detect if the screen is held or not...
Main_Layout.setOnTouchListener(new View.OnTouchListener() {
#SuppressLint("ResourceAsColor")
#Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE:
Main_Layout.setBackgroundColor(R.color.green);
event.setAction(MotionEvent.ACTION_DOWN);
break;
default:
Main_Layout.setBackgroundColor(R.color.blue);
break;
}
return false;
}
});
Related
I have a custom view which acts as a button. I am drawing all the canvas myself. Now I'm making an outline when ACTION_DOWN and remove it after ACTION_UP or ACTION_CANCEL.
#Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
Log.e("test", "ACTION_DOWN");
break;
case MotionEvent.ACTION_UP:
Log.e("test", "ACTION_UP");
break;
case MotionEvent.ACTION_CANCEL:
Log.e("test", "ACTION_CANCEL");
break;
}
return true;
}
This can work for me, except now it is blocking another gesture behind this view which is detecting ACTION_MOVE (scroll left).
If I return false, then it is working fine but now ACTION_UP is not called.
I want to call ACTION_UP if finger is lifted, but pass events down otherwise.
Have you tried overriding dispatchTouchEvent?
https://developer.android.com/reference/android/view/View.html#dispatchTouchEvent(android.view.MotionEvent)
UPDATE:
So touch events are a bit of a beast. The rundown of it is this...
They bubble up at first from your root container in your Activity. This is done by calling dispatchTouchEvent and then onInterceptTouchEvent assuming intercepting wasn't blocked by a child view.
If no view intercepts the event, it will bubble to the leaf node (such as a button) where onTouch is called. If the node doesn't handle it (returns true) its parent gets a chance and so on.
This means that you can use dispatchTouchEvent or onInterceptTouchEvent to spy on touch events without changing the behavior. Unless you're actually going to intercept the event I suggest using dispatchTouchEvent as it's guaranteed to run whereas intercepting may be blocked (example: DrawerLayout will intercept touch events near the edge in order to open the drawer).
So the final result is:
public class MyView extends Button {
#Override
public boolean dispatchTouchEvent(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
Log.e("test", "ACTION_DOWN");
break;
case MotionEvent.ACTION_UP:
Log.e("test", "ACTION_UP");
break;
case MotionEvent.ACTION_CANCEL:
Log.e("test", "ACTION_CANCEL");
break;
}
return super.dispatchTouchEvent(event);
}
}
UPDATE:
Sorry, so I've been under the impression for some reason (mostly my poor reading) that we were dealing with the parent. Here's what I would do...
Go ahead and implement onTouch and return true to consume all the events. This means that any touch events that start on your view will be eaten up. What we'll do then is translate the point to the parent's coordinate space and manually pass the touch event up, it'll look like this inside your custom view...
private boolean passingTouchEventToParent = true;
final private Rect hitRect = Rect();
#Override
public boolean onTouch(MotionEvent event) {
// Handle your custom logic here
final ViewParent viewParent = getParent();
if (passingTouchEventToParent &&
viewParent != null &&
viewParent instanceof View) {
// Gets this view's hit rectangle in the parent's space
getHitRect(hitRect);
event.offsetLocation((float) hitRect.left, (float) hitRect.top);
passingTouchEventToParent = viewParent.onTouchEvent(event);
}
if (event.getActionMasked() == MotionEvent.ACTION_UP) {
// Motion event finished, reset passingTouchEventToParent
passingTouchEventToParent = true;
}
return true;
}
I am working on an Audio Recording App. It works in a way that when the user presses and moves the record button, the button moves along with the finger. I have created a boundary and when the finger crosses that boundary I want the button to perform the hide() animation and get back to it orginal position.
The whole process works fine if the MotionEvent.ACTION_UP or MotionEvent.ACTION_CANCEL event is occurred, but the hide() operation is not occurring even if the touch crosses the boundary. The button plays a back and forth motion sometimes when it is outside the boundary. The touch event is still being called even if I set the visibility of the view to false.
I get the output in the logcat as well (Log.e("MSG","boundary crossed");).
This is the code:
int recordButtonStartX;
microPhoneListner=new View.OnTouchListener() {
#Override
public boolean onTouch(View v, final MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
recordButtonStartX = (int) event.getX();
this.floatingRecordButton.display(event.getX());
}
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
this.floatingRecordButton.hide(event.getX());
break;
case MotionEvent.ACTION_MOVE:
int tempX = (int) event.getX();
if ((recordButtonStartX - tempX) > 200) {
Log.e("MSG","boundary crossed");
this.floatingRecordButton.hide(event.getX());
}
else
{
this.floatingRecordButton.moveTo(event.getX());
}
break;
}
recordMsgButton.setOnTouchListener(microPhoneListner);
To release the onTouchListener for any View set the listener to null.
recordMsgButton.setOnTouchListener(null);
or
After your condition satisfied you can set other listener to that View.
Make another listener
public final OnTouchListener mTouchListener = new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent rawEvent) {
return false;
}
};
When you want to disable the listener then set other listener to that view
v.setOnTouchListener(mTouchListener);
I want to increase the width of a line dynamically as long as the user touches the screen. I used the following code :-
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
stopX++;
}
return true;//EDITED (FORGOT TO PASTE THIS LINE)
}
I make the line from 0 to stopX and y-axis is constant as long as the screen is touched. But, I failed. The line increases in width(as required). BUT, the line increases in width only when the screen is touched, i.e., when I touch the screen, the line increases by 1 BUT THE GROWTH DOES NOT CONTINUE AS LONG AS I TOUCH IT. I hope that I was able to make you understand my problem. Any help will be appreciated. Thanks in advance for any help.
This is because MotionEvent.ACTION_DOWN is fired once when you touch the View. You will need it for e.g. to start a loop that increments stopX in event MotionEvent.ACTION_DOWN and stop it in MotionEvent.ACTION_UP. For e.g.:
Thread t;
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
t=new Thread(new Runnable(){
#Override run(){
while(true){
try{
stopX++;
Thread.sleep(500);
}catch(ThreadInterruptedException e){
break;
}
}
}
});
t.start();
}
return true;
case MotionEvent.ACTION_UP:
t.interrupt();
return true;
}
Try doing something like this (just make sure to add the relevant lock where needed in order to keep the m_Task safe).
I would also consider running the task with a timer in order to prevent some busy waiting.
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
// Start an async task
// Add a lock
m_Task = new LineIncreamentTask(...);
task.Start();
}
case MotionEvent.ACTION_UP:
// Cancel the task
// Add a lock
if (m_Task != null) m_Task.cancel();
}
return true;//EDITED (FORGOT TO PASTE THIS LINE)
}
private class LineIncreamentTask
{
public void doInBackground(...)
{
// Increase the line width
// Update the UI & whatever
}
public void onPostExecute(...)
{
if (!isCanceled())
{
// Add a lock
// Consider using a timer to prevent busy waiting
m_Task = new LineIncreamentTask(...);
m_Task.start();
}
}
}
When I touch the screen and move my finger I do something (pullanimation1 and 2) and when I release the screen I do something else (fireanimation1 and 2). Sometimes, the user might touch the screen while pullAnimation or fireAnimation is running, I get errors as the animation then run several times. I would like to make sure the animations won't run more then once when the user touch again the screen.
NB: pullAnimation1 and 2, fireAnimation 1 and 2 are AnimationDrawable
Here is what I've done :
image2.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
boolean bool=false;
boolean bool2=true;
int action = arg1.getAction() & MotionEvent.ACTION_MASK;
switch (action) {
case MotionEvent.ACTION_DOWN:
if (bool2) {
startAnimation(pullAnimation1,pullAnimation2);
bool=true;
}
break;
case MotionEvent.ACTION_MOVE:
if (bool2==true){
Log.w("GAMEACTIVITY","move");
bool=true;
bool2=false;
}
break;
case MotionEvent.ACTION_UP:
startAnimation(fireAnimation1,fireAnimation2);
bool=false;
doPhotoTask();
bool2=false;
break;
}
return bool;
}
});
I think you should be able to use the hasStarted() and hasEnded() methods to determine if your animation is currently going. See the docs for more
Some if statement like this might work:
if((fireAnimation1.hasStarted() == false) || (fireAnimation1.hasEnded == true()){
startAnimation(fireAnimation1, fireAnimation2);
}
I imagine you may also need to use reset() after it is done playing in order or the methods to return proper values next time touch happens.
EDIT:
AnimationDrawable has an isRunning() method, which makes it even easier than View animations.
if(fireAnimation1.isRunning() == false){
startAnimation(fireAnimation1, fireAnimation2);
}
Ok... in my app i update the layout on MotionEvent.ACTION_DOWN and then i check the motion event coordinates to locate my buttons. I can show a toast when finger is released on different buttons. The problem is i need a long touch on my buttons to call another action without conflicting with the MotionEvent.ACTION_UP. Implemented a long click handler but since i don't 'click' its not working. Hope you guys understand my problem.
Whats the best way to get my app working as intended?
My class implements OnTouchListener, OnGestureListener
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
// UPDATE LAYOUT
break;
case MotionEvent.ACTION_UP:
// GET BUTTON X Y
if (x and y match the button location){
// DO ACTION
}else{
// DO NOTHING
}
// CHANGE LAYOUT TO INITIAL STATE
break;
case MotionEvent.ACTION_MOVE:
break;
}
return false;
mybutton.setOnLongClickListener(new OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
// DO STUFF
return true;
}
});
}
just try to return false in your onTouch(...) method and use onLongClickListener(...) as usual