Develop Reference

Android touch event stucked in ListView

I have a container View that should process touches. It has Listview with overrided onTouch(), which returns false (it will return true, when container is expanded by swipe). When Listview touch occurs it passes to container View and everything is ok. But I need to add click handling for items of Listview.
When I set onClickListener for item, I see in logs it is no MotionEvent passed to container, it is stucked in ListView onTouch() (which return false and does nothing). I'm trying to set onTouchListener for item like this:
viewHolder.itemLayout.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
return true;
case MotionEvent.ACTION_MOVE:
return false;
case MotionEvent.ACTION_UP:
Log.d(TAG, "something like click detected");
return true;
}
return false;
}
});
But result is the same. Can someone explain why my container does not receive touch event even ListView returns false for its overrided onTouch()?

If you wish to handle the clicks of ListView items : use OnItemClickListener
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//parent.getItemAtPosition(position) returns the value of item clicked.. use it to do whatever you wish to do
}
});

I had the same problem about 2 weeks ago. Returning false from listview's onTouch method did not pass event to parent container. I ended up doing this:
1. You need custom layout for your container View. Then in that view, override onInterceptTouchEvent, for example like this:
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
previousX_actionDOWN = ev.getRawX();
isOnClick = true;
timePressed = System.currentTimeMillis();
return false;
case MotionEvent.ACTION_MOVE:
if (isOnClick && (Math.abs(previousX_actionDOWN - ev.getRawX()) > SCROLL_THRESHOLD)) {
return true;
} else {
return false;
}
case MotionEvent.ACTION_UP:
if (!wasDragged) {
return false;
}
else {
return true;
}
}
return false;
}
I also have complicated onTouch method in that view but it's not worth pasting. Point is that your parent view should only intercept touch event if some threshold was passed while ACTION_MOVE - well at least that's what I wanted to achieve. Then in your listview you just implement standard onItemClickListener instead of onTouch.

Android - preview by press and hold

I have a listview that contains some items, i want to allow the user to preview the data of a specific item by pressing and holding on the item. i want the preview window/popup to stay showed as long as the user is pressing.
I am trying to achivie the same preview functionality in IOS and instagram
i already implemented on longpress but not sure what to is the best thing to show to get a the desired result
lv.setAdapter(arrayAdapter);
lv.setLongClickable(true);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
int pos, long id) {
Log.v("long clicked", "pos: " +pos);
return true;
}
});
any hints on how to implement that or best way to implement it ?

Well I'm using recycler view with images.
To show the image I use the long press listener calling this method:
public void publicationQuickView(Post post){
View view = getLayoutInflater().inflate( R.layout.quick_view, null);
ImageView postImage = (ImageView) view.findViewById(R.id.ivFeedCenter);
ImageView profileImage = (ImageView) view.findViewById(R.id.ivUserProfile);
TextView tvUsername = (TextView) view.findViewById(R.id.txtUsername);
tvUsername.setText(post.user.name);
Picasso.with(this).load(post.picture).priority(Picasso.Priority.HIGH).noPlaceholder().into(postImage);
Picasso.with(this).load(post.user.picture).noPlaceholder().into(profileImage);
builder = new Dialog(this);
builder.requestWindowFeature(Window.FEATURE_NO_TITLE);
builder.getWindow().setBackgroundDrawable(
new ColorDrawable(Color.TRANSPARENT));
builder.setContentView(view);
builder.show();
}
I inflate the layout and inject into a Dialog.
To dismiss the dialog I'm using the RecyclerView.OnItemTouchListener() like this:
rvUserProfile.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
#Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
if(e.getAction() == MotionEvent.ACTION_UP)
hideQuickView();
return false;
}
#Override
public void onTouchEvent(RecyclerView rv, MotionEvent event) {
}
#Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}});
And finally:
public void hideQuickView(){
if(builder != null) builder.dismiss();
}

You could add a custom OnTouchListener to the view that represents a given item in you ListView (or RecyclerView or whatever). This allows you to detect when a gesture starts (i.e. first finger down) end ends (i.e. last finger up) or is canceled (e.g. gesture was actually a scroll and has been intercepted by the ListView).
The code you need to do that would look something like that:
itemView.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
int actionMasked = event.getActionMasked();
switch (actionMasked) {
case MotionEvent.ACTION_DOWN:
// show preview
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
// hide preview
break;
default:
}
return true;
}
});
Edit: You may need to include some logic to detect a simple tap (e.g. measure if the whole gesture lasted not longer than ViewConfiguration.getTapTimeout()) and call v.performClick().

See the following answer on how to handle long press with recycler view: RecyclerView onClick
Once you have that, you can show a layout to display your data.

Check this out...
Implement a listener on long click listener
how to implement a long click listener on a listview
and then enable the visibiity of a hidden view. While doing that of course check this link out on how to enable dynamic position of the preview pane
How can I dynamically set the position of view in Android?

Android recyclerview drag and drop custom fetures

I'm trying to develop a simple but custom drag and drop feature of recyclerview items. The idea is to drag a child to a specific view, represented by a FrameLayout, that is not a child of recyclerview.
When a child is dropped onto it it will be deleted otherwise it will simply return to its original position.
I can easily achieve this behaviour without any animation effect, but my purpose is to have smooth animation on the UP dragevent and on the restoration of the element. Now whenever a child is dragged, I create a DragShadow of it and I delete the child in the dataset and notify the removal with adapter.notifyItemRemoved(position).
The last one allows me to have simple remove animation provided by Recyclerview itself.
The Code will explain the mechanism better than words:
public boolean dragNdrop(View arg1, int position) {
// ------------------------
final RecyclerAdapter adapter= ListItemFragment.getAdapter();
/*Keep track of the position and the object for restoring purpose*/
ListItemFragment.indexAbruptedRemoved=position;
ListItemFragment.itemAbruptedRemoved=adapter.getItem(position);
ClipData clipData = ClipData.newPlainText("", "");
View.DragShadowBuilder dsb = new View.DragShadowBuilder(arg1);
arg1.startDrag(clipData, dsb, arg1, 0);
adapter.remove(position);
adapter.notifyItemRemoved(position);
//--------------------
}
getter method for the adapter:
protected static RecyclerAdapter getAdapter() {
return (RecyclerAdapter) recList.getAdapter();
}
dragNdrop is called by a drag listener in the custom adapter:
public void onBindViewHolder(MyHolder myHolder, int position) {
//----------------------------------
myHolder.rowCard.setLongClickable(true);
myHolder.rowCard.setOnClickListener(new MyClickListener.ContainerListener(context,
myHolder.getAdapterPosition(), rowObject, myHolder.imagePreView));
myHolder.rowCard.setOnLongClickListener(new MyClickListener.DragListener(context,
myHolder.getAdapterPosition(), myHolder.rowCard));
//----------------------------------
}
LongCLickListener:
static class DragListener implements View.OnLongClickListener {
private Context context;
private int position;
private View dragged;
DragListener(Context context, int position, View dragged) {
this.context = context;
this.position = position;
this.dragged = dragged;
}
#Override
public boolean onLongClick(View v) {
return ((MainActivity) context).dragNdrop(dragged, position);
}
}
The FrameLayout called trashPanel has the following code:
trashPanel.setOnDragListener(new View.OnDragListener() {
#Override
public boolean onDrag(View view, DragEvent dragEvent) {
int dragAction = dragEvent.getAction();
View dragView = (View) dragEvent.getLocalState();//this
//is properly the object we 've passed with startdrag()
switch (dragAction) {
case DragEvent.ACTION_DRAG_EXITED:
imageView.setImageDrawable(getResources().getDrawable(R.drawable.bowl));
break;
case DragEvent.ACTION_DRAG_ENTERED:
imageView.setImageDrawable(getActivity().getResources().getDrawable(R.drawable.waste));
break;
case DragEvent.ACTION_DRAG_ENDED:
ended(view, dragEvent);
break;
case DragEvent.ACTION_DROP:
Log.i(TAG,"HALOOOOO DROPPED");
drop();
break;
}
return true;
}//[m] end on drag
private void drop() {
String itemToRemove = itemAbruptedRemoved.getSessionName();
Toast.makeText(getActivity(), "DELETED: " + itemToRemove+
" list length:"+items.size()+" adapter length:"+mAdapter.size(),
Toast.LENGTH_SHORT).show();
/**
* HAPTIC FEEDBACK
*/
Vibrator v = (Vibrator) getActivity().getSystemService(Service.VIBRATOR_SERVICE);
long pattern[] = {25, 25, 50};
v.vibrate(pattern, -1);// -1 to not repeat
}
private void ended(View view, DragEvent dragEvent) {
if ( dropEventNotHandled(dragEvent) ) {
mAdapter.insert(itemAbruptedRemoved, indexAbruptedRemoved);
mAdapter.notifyItemInserted(indexAbruptedRemoved);
//********---------->mAdapter.notifyDataSetChanged();
Log.i(TAG,"AGGIUNTO");
}
//change the image inside trash_panel
imageView.setImageDrawable(getActivity().getResources().getDrawable(R.drawable.bowl));
//due to implementations detail it must be done in this way(otherwise mutithread exception is throwned)
view.post(new Runnable() {
public void run() {
/**
* Set animation for fabNew Button and trash_panel
* in order to make them smoothly disappear
* and place them in their original positions
*
*/
------------------------------------
}
});
}
private boolean dropEventNotHandled(DragEvent dragEvent) {
return !dragEvent.getResult();
}
});
The problem is that sometimes when I start to drag an item, I obtain the correct DragShadow, but the item removed is wrong.
In the code i higlited with ***----> the call to notifyDataSetChanged(), because if i call it, things work properly, but without animation.
I know there are utility classes such as ItemTouchHelper.Callback that should be used to manipulate the movement and animation of recyclerlist children, but I can't figure out how to manage to make them do what I want to do. I saw a couple of methods that could be used to achieve this, such as onChildDrawOver and onChildDraw, but i still don't know how to use them in order to intercept dragevent.DROP . I also know the existence of the interface for the LLM called ItemTouchHelper.ViewDropHandler that has the abstract method prepareForDrop, but I still don't know how to use it in a proper way.
Thanks in advance to everyone who will help me!

Take a look at ItemTouchHelper. It will allow you customize your drag drawing. See Support7Demos for an example implementation.

Simultaneous GridView button events/determining which button has been touched

I'm having a hard time trying to figure this out. I have a gridview of 8 buttons. At the moment I'm using an onItemClickListener to trigger the buttons actions, however this produces two problems for me.
1) The buttons action happens after the button has been unpressed.
2) Two buttons cannot the pressed at the same time, you must release the first button.
As I have learnt, an onTouchListener should resolve my first issue, though I'm not sure how to determine which button has been pressed. My code for the onItemClickListener is as follows
gridview.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
Toast.makeText(Activity.this, "" + position, Toast.LENGTH_SHORT).show();
}
});
Now with the above, I know exactly which button has been pushed. I believe the code for implementing as an onTouchListener is as follows
gridview.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
return false;
}
}) {
How am I supposed to determine which button has been pressed using MotionEvent? Before I was getting passed 'position' and it made this fairly easy. I also need to account for if two or more buttons have been pushed simultaneously/without letting another one go.
Does anyone know how to achieve this?

Having hit this very issue recently and coming across this post in my quest for help, I wanted to add two things from what I did which seem to have worked:
1) I added the onTouchListener to the object in the adapter rather than the activity or gridview.
2) In the OnTouchListener, I looked for MotionEvent.ACTION_DOWN (first finger touch) and MotionEvent.ACTION_POINTER_DOWN (subsequent finger touches), this way I can get multitouches and process them immediately without waiting for the user to lift their finger(s).
Note that I called it ImageAdapter, even though I've added a TextView to each as that way I can use the TextView background for the image, but add invisible text to the TextView so it works with Talkback):
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return numCols * numRows;
}
public Object getItem(int position) {
return this;
}
public long getItemId(int position) {
return position;
}
// create a new TextView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
TextView textView;
if (convertView == null) { // if it's not recycled, initialize some attributes
textView = new TextView(mContext);
} else {
textView = (TextView) convertView;
}
// place any other initial setup needed for the TextView here
// here's our onTouchListener
textView.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
boolean returnValue;
int thePosition = v.getId();
// MotionEvent.ACTION_DOWN gets the first touch
// MotionEvent.ACTION_POINTER_DOWN gets any subsequent touches (if you place a second finger on the screen)
// Between these I can get touches as soon as they happen, including multitouch support, without needing to wait until the user lifts their finger.
if ((event.getAction() == MotionEvent.ACTION_DOWN) || (event.getAction() == MotionEvent.ACTION_POINTER_DOWN)) {
TextView textView;
if (v == null) { // if it's not recycled, initialize some attributes
textView = new TextView(mContext);
} else {
textView = (TextView) v;
}
// Do any processing based on the touch - I call a function and pass the position (number of cell, 1..n) and textview so can make changes to it as needed
ScreenTapped(thePosition, textView);
// I used a returnValue
returnValue = true;
} else returnValue = false;
return returnValue;
});
return textView;
} // getView
} //imageadapter

I am infact trying to figure the same thing out. I got as far as figuring out which gridcell has been clicked using the following code
public boolean onTouch(View v, MotionEvent me) {
float currentXPosition = me.getX();
float currentYPosition = me.getY();
int position = gridView.pointToPosition((int) currentXPosition, (int) currentYPosition);
Position gives you the number on the gridView, and you can supposedly retrieve that particular item as following
gridView.getItemAtPosition(position)
But that is where I am stuck. My gridView has Textview items in it, and I am having trouble converting the item to a textview and then performing operations on it.
Hope this helps!

When using gridView the philosophy is:
the grid view implements the onTouchLister
when touch happens onTouchLister gathers the coordinates (a lot :) )
for all ACTION_MOVE events
when the touch event is MOVE_UP, calculate the real positions under
the coordinates and return the item in the grid
So the solution would be:
In your activity where you have findViewById(some_grid_view)
//Register handler for the onTouch event of gridView in your activity
gridView.setOnTouchListener(new MyActivityOnTouchListener(this));
NOTE: my onTouch listener is implemented in another class (MyActivityOnTouchListener) instead of inside the activity
...then in the MyActivityOnTouchListener class you implement the onTouch method:
public class CalendarActivityOnTouchListener implements View.OnTouchListener {
private MyActivity myActivityContext;
private GridView mGridView;
private HashSet<Point> movementCoordinates = new HashSet<Point>;
//Constructor
public MyActivityOnTouchListener (MyActivity context){
this.myActivityContext= context;
mGridView= myActivityContext.getGridView(); //assign touched gridView into a local variable
}
#Override
public boolean onTouch(View v, MotionEvent event) {
/*
* NOTE:
* ACTION_MOVE fires events until you release it
* ACTION_UP once you release it fires it
*/
//while touching the grid a bunch of ACTION_MOVE events are dispatched
if (event.getAction() == MotionEvent.ACTION_MOVE) {
//gather all coordinates touched (in a set to avoid duplicates)
movementCoordinates.add(new Point((int)event.getX(), (int)event.getY()));
return true;
}
//Finally the finger is lifted
if (event.getAction() == MotionEvent.ACTION_UP) {
//convert all movementCoordinates gathered in the previous block into real grid positions
int position;
for(Point p : movementCoordinates){
Log.d("Luka", p.x +" / "+p.y);
position = calendarGridView.pointToPosition(p.x, p.y);
//...Do whatever with the position
}
}
}
}
Be careful about the pointToPosition() method because in some cases it can return -1 instead of the position behind the coordinates. For example, if you have a margin between items in the grid those coordinates cannot return a position, hence the -1
hope it helps...

unable to click views in listview with trackball

I have a listview with clickable buttons in the row views, and a custom SimpleCursorAdapter to implement this list. Despite the onitemclicklistener not being fired when the row is clicked (see here), I have implemented a listener that works when touching the row item:
public View getView(int position, View convertView, ViewGroup parent) {
.................................
convertView.setOnClickListener(new OnItemClickListener(position));
}
public class OnItemClickListener implements OnClickListener{
private int mPosition;
OnItemClickListener(int position){
mPosition = position;
}
public void onClick(View view) {
}
}
There are two problems with this - it takes two touches to fire the onitemclick listener, presumably one to focus and one to fire, and it's impossible to select the row using the trackball.
I have tried some of the workaround listed on SO, inlcuding making the button not focusable, and some other methods here, but didn't get anywhere. As that link points out, Google accomplish it themselves with the call log application. That seems to be achieved with ListActivities though - I am using a Tab Activity with several lists in the same tab.

I managed to sort out both issues in the end with a TouchDelegate. The relevant code I used in my Custom Adapter is below. I used the TouchableDelegate on an ImageView, so I'm pretty sure most other objects would also work. TOUCH_RECT_EXPANSION is just a constant parameter for how much you want the bounding box to be expanded by. Also note that your Custom Adapter must implement View.OnTouchListener.
public View getView(int position, View convertView, ViewGroup parent) {
star = (ImageView) convertView.findViewById(R.id.liststar);
final View parentview = (View) star.getParent();
parentview.post( new Runnable() {
// Post in the parent's message queue to make sure the parent
// lays out its children before we call getHitRect()
public void run() {
final Rect r = new Rect();
star.getHitRect(r);
r.top -= TOUCH_RECT_EXPANSION;
r.bottom += TOUCH_RECT_EXPANSION;
r.left -= TOUCH_RECT_EXPANSION;
r.right += TOUCH_RECT_EXPANSION;
parentview.setTouchDelegate( new TouchDelegate(r,star) {
public boolean onTouchEvent(MotionEvent event) {
return true;
}
});
}
});
star.setOnTouchListener(this);
}
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
// do something here
}
return true;
}
}
I also had some issues with the onItemClickListener. In the end these were solved by using a separate custom class that implemented the interface OnItemClickListener, so try that if you are having problems, but it's probably more likely that I was doing something wrong with the in-class onItemClickListener, because I can't see any reason why that should work differently.