Develop Reference

Move finger across buttons in android apps

When the user touches the button sound shoud be played. There is a lot of buttons, and each has a different sound. When user move finger across all buttons, all sounds should be played. Something like piano app. How can I do it? I tried with ontouch lister but it doesn't work.

Within your onTouch method, you should capture different events starting from user TouchDown followed by TouchMove and finally TouchUp. Look for all x,y co-ordinates whether in your button area, if so, play sound.
Make sure that the current button selection is different than the previous one otherwise, if your finger moves over same button, that'll trigger another event for same button and you'll here tons of sound while moving finger:
psudo code:
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction())
{
case MotionEvent.ACTION_UP: // stop here
break;
case MotionEvent.ACTION_DOWN: // start here
break;
case MotionEvent.ACTION_MOVE:
// See if new x y co-ordinates in your buttonRect area
// RectF [] buttonRect = new buttonRect[10] ;
for(int i = 0; i < 10; i++)
{
if( buttonRect[i].contains(event.getX(), event.getY()))
{
// if it's a new button found than previously touch, play a sound
// store the button number that's been tapped by user
}
}
break;
}
}
Hope it helps.

Unable to detect ACTION_MOVE or ACTION_UP touch events

I am having trouble detecting the MotionEvent.ACTION_MOVE & MotionEvent.ACTION_UP events. I am intending to have a button when you press and hold, it automatically decreases an associated value, however I have not gotten to that point in coding because I cannot detect the UP event.
for (int position = 0; position < mListItems.size(); position++) {
LayoutInflater inflater = getLayoutInflater();
PilotSkillRow row = (PilotSkillRow) inflater.inflate(R.layout.pilotskillrow, mSkillListView, false);
Button skillminus = (Button) row.findViewById(R.id.skillminus);
skillminus.setOnTouchListener(new SkillButtonTouchListener(position, false));
....
}
I understand returning true on the on touch events means that the later ontouch events such as ACTION_MOVE and ACTION_UP should fire.
private class SkillButtonTouchListener implements OnTouchListener {
public SkillButtonTouchListener(int pos, boolean plus) {
...
}
public boolean onTouch(View view, MotionEvent motionevent) {
int action = motionevent.getActionMasked();
switch (action)
{
case MotionEvent.ACTION_MOVE:
Log.e("a", "MOVE EVENT");
....
return true;
case MotionEvent.ACTION_UP:
Log.e("a", "UP EVENT");
....
break;
case MotionEvent.ACTION_DOWN:
Log.e("a", "DOWN EVENT");
....
return true;
default:
break;
}
return false;
}
}
However, when I run the code, the DOWN even it displayed, but the MOVE and UP EVENTS simply are never displayed. Could it be related to the fact I have an inflated layout?
Anyone have any ideas what I am doing wrong?
Update: If I use the android debugger to connect to the button to check what is happening, the UP event fires when I step through after pressing the button. Probably because there is another process consuming the UP event?
Update 2: The problem is that the textview inside an inflated layout refuses to update. When I perform an invalidate event on the adapter, it will stop the currently processing touch events (no errors). I have another textview which I am able to manually update without the need of the adapter and this does not cause any problems. So it seems to be a problem specific towards RelativeLayout. I have a workaround to only invalidate the data during the ACTION_UP event but I'd rather update the textview on the fly.

Maintain sound with key pressed?

Hi I'm using the Soundpool Android to play a sound when I press a button. I wonder if it is possible to maintain this sound playing while the button is pressed.

Here you need to identify the touch events I mean ACTION_DOWN when the button is pressed and ACTION_UP when the user has lifted his finger. You can start playing the sound in when the ACTION_DOWN event occurs and stop it when the ACTION_UP events occur.
Now for catching these events on a button you will have to set onTouch listener on the button and implement it's onTouch() method. onTouch() method is where you will have to catch those events and play/pause the sound.
Here is a sample how you can implement this onTouch() method of the button:
btn.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch (View v, MotionEvent event)
{
switch(event.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN:
//here you can start playing song
break;
case MotionEvent.ACTION_UP:
//here you can stop playing song
break;
}
return false;
}
});
Here you can notice that I have returned false to indicate the os that I am finished with the event and now you can handle the event. If you do not want the os to handle the touch event then return true which indicates that you have consumed the touch event.
I hope this will help.

How to get ViewID on TouchUp Event

I'm implementing Drag Drop of one text view to other text view. I've created OnTouchListener and applied on my both TextViews
I wrote OnTouch Function like this
public boolean onTouch(View v, MotionEvent e)
{
switch(e.getAction())
{
case MotionEvent.ACTION_DOWN:
Log.d("Down",v.getId()+"");
break;
case MotionEvent.ACTION_MOVE:
Log.d("Move",v.getId()+"");
break;
case MotionEvent.ACTION_UP:
Log.d("Up",v.getId()+"");
break;
}
return false;
}
I'm facing a problem in all three cases it returns me ID of the TextView on which first time the touch event is fired. I want to obtain the IDs of other TextViews
For example it just give me ID of Down Event "tv1". And again gives me "tv1" on Move Event and Up Event (despite of my position is changed to other TextView whose ID is tv2)
How can i get the ID of TextView on which Touch Up Event has occurred

Logically you should not expect up event of tv2 . because touchListener will listen once you will touch that view, then repeatedly call until up event occurs .
so in my understanding , handle tv2 touch by calculate x,y coordinates in the only way

Interesting android touch issue

The problem that i am having is I am using a touch listener for the onTouch event it seems that the touch is being called more than once when i just touch it once.
The following is my code
final TextView tv = (TextView)findViewById(R.id.TextView01);
tv.setOnTouchListener(new View.OnTouchListener() {
int count1 =0;
int count2=0;
public boolean onTouch(View arg0, MotionEvent event) {
Log.d("Code777","Touch is being called finger");
int i = event.getPointerCount();
if(i==1 )
{
if(count1==0)
{
Log.d("Code777","Touched with 1 finger");
count1++;
count2=0;
}
}
if (i==2 )
{
if(count2==0)
{
Log.d("Code777","Touched with 2 fingers");
edit.append(tv.getText());
count2++;
count1=0;
}
}
return true;
}
});
Am i doing something wrong ??
It prints the log more than 3-4 times for both single touch and double touch
The problem updated problem is that both the events are getting fired now
if(event.getAction() == MotionEvent.ACTION_POINTER_2_DOWN)
{
Log.d("Code777","2 finger touch");
return true;
}else if(event.getAction() == MotionEvent.ACTION_DOWN)
{
Log.d("Code777","Touched with 1 finger");
return true;
}

You're code will execute during every touch event. The first time it activates, it's likely do to an ACITON_DOWN event (when the user first touches the screen). The second time, it is likely do to an ACTION_UP event (when the user lifts the finger from the screen). Likewise, if you were to swipe your finger around the screen, the same code will execute many times for an ACTION_MOVE event. You have to check for the types of touches that it is. Do something like this:
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
// Do something that should only happen when the user first touches the screen
break;
case MotionEvent.ACTION_MOVE:
// Do something that should only happen when the user is touching the screen
break;
case MotionEvent.ACTION_UP:
// Do something that should only happen when the user stops touching the screen
break;
}
EDIT:
Multitouch in Android is odd at best. Not all devices can handle it. Not all device can handle more than x number of touches, etc. If you want to handle DOWN cases for individual fingers, then you can use the ACTION_POINTER_X items. If you were to have this series of events like so:
1. User touches screen
2. User touches screen with second finger
3. User lifts finger 1
4. User touches screen with finger 1
5. User lifts finger 2
6. User touches screen with finger 2
7. User lifts both finger 1 and finger 2
8. User touches screen with only finger 2
9. User touches screen with finger 1
The events that will be fired will be like this:
1. ACTION_DOWN
2. ACTION_POINTER_2_DOWN
3. ACTION_POINTER_1_UP
4. ACTION_POINTER_1_DOWN
5. ACTION_POINTER_2_UP
6. ACTION_POINTER_2_DOWN
7. ACTION_UP (also, one of the pointers actions will fire depending on which finger was lifted first)
8. ACTION_DOWN
9. ACTION_POINTER_2_DOWN
And so on.

An onTouchListener sends you multiple actions via MotionEvents. You can get the action for the current event with MotionEvent.getAction().
What you notice here is most likely that you get one ACTION_DOWN (a finger has been placed on the display) event followed by some small ACTION_MOVE events when you move the finger(s) slightly. In the end you will get ACTION_UP (a finger has been lifted) You can filter these out by ignoring events with the wrong action.
For example just return from onTouch() when a move event occured.
public boolean onTouch(View arg0, MotionEvent event) {
Log.d("Code777","Touch is being called finger");
if(event.getAction() == MotionEvent.ACTION_MOVE) {
Log.d("Code777", "Move event detected, ignored!");
return false;
}
// Further processing ..
}
or use a switch to differentiate between all relevant events.
See the MotionEvent class documentation for a list of possible actions.
.