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Drag a view onLongClick and start activity onClick

I'm banging my head with this problem which probably is simple but since I'm new to this topic I somehow haven't been able to figure it out yet.
I've successfully implemented dragging a view with onTouch method. I've also successfully implemented onLongClick and onClick methods. But both of these functionalities were implemented separately.
The problem, like the title says is when I want to join these functionalities. I want the onTouch method to be called when a user long clicks a view and I want a new activity to start when a user clicks a view.
Here is the pseudo code:
public class Website extends AppCompatActivity implements View.OnTouchListener{
TextView longpress;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_website);
longpress = (TextView) findViewById(R.id.longpress);
longpress.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view){
//I don't really know how to do this part
onTouch(View view, Motion Event event);
return true;
}
});
longpress.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
//Code for new activity comes here (I know how to do this part)
}
});
}
public boolean onTouch(View view, MotionEvent event) {
switch(event.getAction(){
case MotionEvent.ACTION_DOWN:
//Save initial coordinates of view <-- view.getX(), view.getY()
break;
case MotionEvent.ACTION_MOVE:
//Calculate dX and dY and setX and Y of the view (move view)
break;
case MotionEvent.ACTION_UP:
//If view is certain distance away from initial points do something
break;
}
}
}
Like I said, onTouch works on itself if I don't try to call it from onLongClick method. If I try to call onTouch(View view, MotionEvent event) from onLongClick method the problem occurs because onLongClick only receives one out of two arguments onTouch method should receive (onLongClick only receives view argument but it should also receive event argument).
Maybe I'm trying to do this in a totally wrong way but I have been looking at some documentation e.g. https://developer.android.com/training/gestures/ but still won't get an idea what to do.
(I would like to have a similar functionality to notifications on android phones)

So I've come to a solution which might or might not be a good one but for now it serves my functionality. If someone has a better solution and thinks mine is bad in some way please say so.
Here is the code:
boolean flag;
public boolean onTouch(View view, MotionEvent event){
int action = event.getAction() & MotionEvent.ACTION_MASK;
if(action == MotionEvent.ACTION_DOWN){
//do something on a down press
flag = true;
return true;
}
if(action == MotionEvent.ACTION_UP && flag == true){
//do something if we move finger away from screen we
//didn't move the view first
return true;
}
if(action == MotionEvent.ACTION_UP && flag == false){
//do something if we move finger away from screen and we moved
//the view before we moved the finger away from screen
}
if(action == MotionEvent.ACTION_MOVE){
//do something when moving the view
flag = false;
}

Android GridView Get Position Of Touch In onScroll Event Listener

Im looking at the docs for the onScroll event listener http://developer.android.com/reference/android/widget/AbsListView.OnScrollListener.html
And I don't see an option for getting the position of the touch when a scroll event is occurring.
On iOS I could do
var pan = scrollView.panGestureRecognizer
var globalPoint = pan.locationInView(view)
However on Android I don't see the onScroll parameters with any values for the position of the touch event
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
//where you mr. touch position event? :(
//oh touchevent.position, where art thou?
}
One possible solution I'm considering is adding a view on TOP of the scrollview and listening for that touch position, but I'm hoping there's a better way.
TL;DR How do I get the position of a touch when the GridView was scrolled?

Thankfully the solution turned out to be a lot less complex.
Just add an onTouchListener to the GridView and return false so it doesn't swallow the event.
_gridView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event)
{
System.out.println("Position is " + event.getRawY());
return false;
}
});

Prevent Click-through of Android ImageVIew?

I have an ImageView overlay inside of a RelativeLayout and want to prevent any clicks from going through the ImageView to the Buttons etc that are behind it (thus in effect disabling the entire RelativeLayout).
Is the a simpler way of doing this then iterating the RelativeLayout views and setting them to disabled as I currently am doing using this code:
RelativeLayout rlTest = (RelativeLayout ) findViewById(R.id.rlTest);
for (int i = 0; i < rlTest.getChildCount(); i++) {
View view = rlTest.getChildAt(i);
view.setEnabled(true);
}

you can set the image to be
android:clickable="true"

Simply call rlTest.setClickable(false). This will prevent the click to be propagate to the children

There is a much cleaner way
You can use:
android:onClick="preventClicks"
in XML and in your Activity
public void preventClicks(View view) {}
This works with fragments.
Example inside this Activity has multiple fragments overlapping one another, just by adding the XML attribute in the background of your fragment it will still call the Activity.preventClicks and will prevent touches on fragments behind it

The following solution works in the general case:
_container.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
// NOTE: This prevents the touches from propagating through the view and incorrectly invoking the button behind it
return true;
}
});
It basically blocks any touches from propagating through the view by marking the touch event as handled.
This works on both UI controls and layout containers (ie: LinearLayout, FrameLayout etc.).
The solution to set "clickable" as false did not work for me for layout containers either in code or in the view XML.

I assume that you are using onClickListeners.
How about using onTouchListener instead of onClickListeners. By doing this you will have a control over how deep down in your hierarchy the touch even can be visible. For example, if you have toch listeners on a relative-layout(RL) and a image-view(IV)(contained in RL), and you assign touchListeners to both. Now if you return true from IV's touch event, the lower down member RL will not receive the touch event. However if you return false from from IV's touch event, the lower down member RL will receive the touch event.
Hope this helps!

Just add these two listeners:
// Set an OnTouchListener to always return true for onTouch events so that a touch
// sequence cannot pass through the item to the item below.
view.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
v.onTouchEvent(event);
return true;
}
});
// Set an OnHoverListener to always return true for onHover events so that focus cannot
// pass through the item to the item below.
view.setOnHoverListener(new OnHoverListener() {
#Override
public boolean onHover(View v, MotionEvent event) {
v.onHoverEvent(event);
return true;
}
});

You could use databindings and consume the clicks like this:
android:onClick="#{() -> true}"

In C#, I use an empty delegate:
objectName.Click += delegate {};
I haven't encountered any problems with it but it does prevent clicks from filtering through to underlying controls.

you can also se the root click listener to null:
// Do not process clicks on other areas of this fragment
binding.root.setOnClickListener(null)
This works 100%.
It doesnt affect other listeners that are already set on the fragment's views.

Drag and Drop in a `ListView`

I am trying to implement a drag and drop in a ListView in android(Ice Cream Sandwich). So when the dragged object reaches the edge of the ListView, I am scrolling the ListView in the relevant direction. The problem is that when we scroll, sometimes the adapter creates new Views as necessary and these 'new' Views did not receive the ACTION_DRAG_STARTED event earlier and hence do not receive the DragEvent updates. Is there any way I can send the events to these views as well?

An easiest way to implement drag and drop in listview is you use this great library.
https://github.com/commonsguy/cwac-touchlist
it's worth trying.

Looking at the source for View, I see:
static final int DRAG_CAN_ACCEPT = 0x00000001;
int mPrivateFlags2;
boolean canAcceptDrag() {
return (mPrivateFlags2 & DRAG_CAN_ACCEPT) != 0;
}
mPrivateFlags2 is package-private and not exposed by the SDK. However, you should be able to change it in a subclass by doing:
try {
Field mPrivateFlags2 = this.getClass().getField("mPrivateFlags2");
int currentValue = mPrivateFlags2.getInt(this);
mPrivateFlags2.setInt(this, currentValue | 0x00000001);
} catch (Exception e) {
}

I have the same problem. I did not solved this recycling problem, but I found a possible workaround still using the Drag & Drop framework. The idea is to change of perspective: instead of using a OnDragListener on each View in the list, it can be used on the ListView directly.
Then the idea is to find on top of which item the finger is while doing the Drag & Drop, and to write the related display code in the ListAdapter of the ListView. The trick is then to find on top of which item view we are, and where the drop is done.
In order to do that, I set as an id to each view created by the adapter its ListView position - with View.setId(), so I can find it later using a combination of ListView.pointToPosition() and ListView.findViewById().
As a drag listener example (which is, I remind you, applied on the ListView), it can be something like that:
// Initalize your ListView
private ListView _myListView = new ListView(getContext());
// Start drag when long click on a ListView item
_myListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
view.startDrag(null, shadowBuilder, _myListView.getItemAtPosition(position), 0);
return true;
}
});
// Set the adapter and drag listener
_myListView.setOnDragListener(new MyListViewDragListener());
_myListView.setAdapter(new MyViewAdapter(getActivity()));
// Classes used above
private class MyViewAdapter extends ArrayAdapter<Object> {
public MyViewAdapter (Context context, List<TimedElement> objects) {
super(context, 0, objects);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View myView = convertView;
if (myView == null) {
// Instanciate your view
}
// Associates view and position in ListAdapter, needed for drag and drop
myView.setId(position);
return myView;
}
}
private class MyListViewDragListener implements View.OnDragListener {
#Override
public boolean onDrag(View v, DragEvent event) {
final int action = event.getAction();
switch(action) {
case DragEvent.ACTION_DRAG_STARTED:
return true;
case DragEvent.ACTION_DRAG_DROP:
// We drag the item on top of the one which is at itemPosition
int itemPosition = _myListView.pointToPosition((int)event.getX(), (int)event.getY());
// We can even get the view at itemPosition thanks to get/setid
View itemView = _myListView.findViewById(itemPosition );
/* If you try the same thing in ACTION_DRAG_LOCATION, itemView
* is sometimes null; if you need this view, just return if null.
* As the same event is then fired later, only process the event
* when itemView is not null.
* It can be more problematic in ACTION_DRAG_DROP but for now
* I never had itemView null in this event. */
// Handle the drop as you like
return true;
}
}
}
Now if you need to have a visual feedback when doing a drag and drop, there are several strategies. You can for instance have 2 instance variables in your activity named:
private boolean ongoingDrag = false; // To know if we are in a drag&drop state
private int dragPosition = 0; // You put the itemPosition variable here
When doing the drag and drop in MyListViewDragListener you modify these variables, and you use their state in MyViewAdapter. Of course do not forget to update the UI (in the event thread of course, use a Handler) with something like _myListView.getAdapter()).notifyDataSetChanged() or maybe _myListView.invalidate() method.

The problem is because listView.getPositionForView(view) returns -1 if the view is not visible when it is called. So relying on that will fail when you scroll the list. So, instead of setting a view.setOnLongClickListener() you can set a listView.setOnItemLongClickListener() on the list item which calls startDrag() on the item. onItemLongClick() gives you the position which you can pass to in the myLocalState parameter of startDrag(). Then you recover that in onDrag() using event.getLocalState() and casting it to an Integer. Like this...
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
position -= listView.getHeaderViewsCount();
DragShadowBuilder dragShadow = new View.DragShadowBuilder(view);
view.startDrag(null, dragShadow, position, 0);
return true;
}
});
Then in your OnDragListener...
#Override
public boolean onDrag(View eventView, DragEvent event) {
Integer dragViewPos = ((Integer) event.getLocalState());
int eventViewPos = listView.getPositionForView(eventView) - listView.getHeaderViewsCount();
...
}

2 Simultaneous Android Touches / not triggered

So hi there.
I have a simple Layout with 2 Views in it. Both have an onTouchListener attached.
view.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent event) {
System.out.println("Touching");
return false;
}
});
But when I open the application on my phone and touch the first view and do NOT relase my finger and touch the second view with another finger, the second view wont trigger the touch event. why is this so?

I think in this case both touches are passed to the first view as a multi-touch event. So this is one event but contains (I forgot the details) both touch positions.