Develop Reference

How to swap items from two recyclerview items that are in two fragments in one activity?

I have two fragments (a and b) inside an Activity according to the picture below.
I am able to delete from first one but how to add that item to favorites fragment RecyclerView?
Deleting actress name and adding to favorites
My Viewholder code for RecyclerView Fragment one class:
addToFavoriteButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mArrayList.remove(getAdapterPosition());
notifyDataSetChanged();
}
});
How to add this deleted item inside adapter of Favorites Recyclerview?

What I would do is maintain a list of actresses (either locally or on the server) with each one containing an isFavorite boolean attribute.
Then, while you have one global list, each recyclerview is only showing a subset:
On the left, you show all actresses where isFavorite is set to false.
On the right, you show all actresses where isFavorite is set to true.
How you update it could be done a few different ways, but here is what I recommend at a high level:
Have an onClick listener for each one that bubbles up to the activity, so the activity is aware any time an actresses's favorite state changes. Every time the state changes for an actress, tell your adapters in each fragment to update.
If you don't want to refresh the entire list every time, you could integrate a remove and add method like Mauker's Answer.

You can create a method inside your adapter that removes an item from the RecyclerView, and returns the given item.
Then, you can use this item reference to add it to the second RecyclerView.
Pseudocode example
public myItem removeAndGetItem(int position) {
myItem item = mArrayList.get(position);
mArrayList.remove(position);
notifyDataSetChanged();
return item;
}
Then you could call something like (also, pseudocode):
myItem item = adapter1.removeAndGetItem(position);
adapter2.add(item);
Adjust the examples to your code, and it should do the trick.
Edit
I misread the part about the RecyclerViews being on different Fragments.
So, you can still do what I said on the example above, you'll just have to pass that item to the second Fragment, using Fragment callbacks, or Broadcasting the item, or even through an EventBus.
Instead of using notifyDataSetChanged() which can be very costly, try to use notifyItemRemoved(int position) instead. As you can see on the docs:
If you are writing an adapter it will always be more efficient to use the more specific change events if you can. Rely on notifyDataSetChanged() as a last resort.

Synchronize ListView scroll position

I am trying to synchronize ListViews scroll positions in a ViewPager.
I have a ViewPager with Fragments as children. Each fragment contains a ListView. I created a ListViewScrollListener interface, with which I listen to each ListView scroll activity. When one ListView is scrolled by the user, the active fragments in the ViewPager listen to the scroll event and call the following method on their ListView:
listView.setSelectionFromTop(firstVisibleItem, pixelOffset);
Sadly, the scroll positions of the ListView elements in the Fragments do not update. When I put the same setSelectionFromTop method in the onResume() method, it works like a charm, hence the position is set correctly when I swype the ViewPager and the Fragments are being created.
I also checked out StackOverflow for similar problems and tried the following solution, without positive results:
mListView.post(new Runnable() {
#Override
public void run() {
listView.setSelectionFromTop(firstVisibleItem, pixelOffset);
}
});
I checked if the setSelectionFromTop is called correctly, and apparently it is. Any ideas why it's not working?
Update 1
As hinted by Ne0, I also checked to run the setSelectionFromTop method inside the Fragment on the main ui thread, without any positive results.
getActivity().runOnUiThread( new Runnable() {
#Override
public void run() {
listView.setSelectionFromTop(firstVisibleItem, pixelOffset);
}
});
Any other ideas what this could be?

Android: reference to view outside fragment | gesture listener in fragments

I have a TextView in a fragment where I want to set different texts when the gesture is detected.
#Override
public boolean onTouchEvent(MotionEvent event) {
this.gestureDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
The above code is used to listen for gesture, but it can only be used in an Activity class somehow, when I put .onTouchEvent() in a fragment class, it says cannot resolve method. Any idea how I can manipulate a view from outside the fragment or any ways to basically listen for the gestures like I did in the Activity class??

You can add touch listeners to views, so get the root view of that fragment, and add your listener with view.setOnTouchListener(...)

OnClickListener for many views

I have done some onclick listeners before in earlier projects but i have have never done like 100-200 onclicks. The idea is a horizontal scroll that AddImagViews to it if a variable is == somethin and if you click the imageview the imageview will setText to an TextView.
I have done the set imageview part but is there any easier way then creating like 100 different onclick for each imageview. Sorry if this was bad explained and difficult to understand.

Sure, have your Activity implemenent OnClickListener something like:
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.splash_startScan:
// do something
break;
case R.id.splash_startReview:
// do something
break;
}
}
then for each button do
button.setOnClickListener(this);

You can create a generic onClick event that reacts to the view that is passed to it. You can use a decision statement (like an if statement) to determine the button, but if all you need is the text from the button you can get that generically by casting the view back into a button and getting its text.
Button button = (Button)v;
button.getText().toString();

Might be best to create a class that implements onClickListener and has a constructor that passes in what you need and then just set the listener to a new instance of that object with the right parameters.

Event handle on customized ListView

public class ActivityForShow extends Activity
{
//have a ListView layout
ListView.setAdapter(SingleRowAdapter);
}
public class SingleRowAdapter extends ArrayAdapter
{
//every row has a CheckBox ,a TextView and a Button
}
Now I want to handle CheckBox and Button events,do some background work and show result in a dialog.
But how to getRefences of Checkbox and Button in ActivityForShow?
findViewById() will cause Exception.

I don't think you want to do that in the ActivityForShow class. Instead, register all event handlers inside of your SingleRowAdapter#getItem(int) method (you will have have to override this). In that method you create the view for the given row, so you know what the row is (position) and you can register event handlers for the CheckBox, Button, etc

It sounds like you want to handle the onCheckedChanged event or onClick event in ActivityForShow.
If so, have ActivityForShow create a OnCheckedChangeListener instance and OnClickListener instance (e.g. as local anonymous inner classes) and have ActivityForShow give them to SingleRowAdapter (e.g. as constructor params) to attach to the checkbox and button widgets as their callbacks.
Alternatively, define your own custom handler interface(s) to be called when the button is clicked or the checkbox is checked. Have ActivityForShow to instantiate an instance of the custom interface(s) with code to process the event. Have ActivityForShow give them to SingleRowAdapter. Finally, have SingleRowAdapter create event handlers to attach to the checkboxes and buttons - these event handlers simply call your own custom handlers.

Hope the following link may help you, event on an item of ListView custom row layout.

It's obvious it gives error with finviewbyid method because it is used for when reference by xml ele. You can use this link for study:
http://developer.android.com/reference/android/widget/ArrayAdapter.html