Spinner not working inside ViewGroup - spinner

Question

From last few days Im trying to get Spinner working in ViewGroup without any success. :-{.
Inside custom ViewGroup I placed fragment container.
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:boxMenu="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".TestActivity"
android:id="#+id/frame" >
<com.imper.boxmenulibrary.BoxMenuLayout
android:id="#+id/box_menu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
boxMenu:boxSize="40dp"
boxMenu:directionY="bottomToTop"
boxMenu:directionX="rightToLeft"
boxMenu:showStart="false"
android:padding="5dp"
android:background="#ffffff00">
<LinearLayout
android:id="#+id/fragment_container"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="top|center"
android:orientation="vertical">
</LinearLayout>
</com.imper.boxmenulibrary.BoxMenuLayout>
In that fragment container Im replacing fragment like this:
FragmentManager fm = ((Activity) context).getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragment_container, new TestFragment());
ft.commit();
My TestFragment xml layout looks like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<Spinner
android:id="#+id/test_spinner"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
And TestFragment implementation looks like this:
public class TestFragment extends BoxLayout implements OnItemSelectedListener {
Spinner testSpinner;
public TestFragment() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstance) {
View view = inflater.inflate(R.layout.test_view, container, false);
testSpinner = (Spinner) view.findViewById(R.id.test_spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(container.getContext(), R.array.day, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
testSpinner.setAdapter(adapter);
testSpinner.setOnItemSelectedListener(this);
return view;
}
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
Toast.makeText(getActivity(), "Bingo", Toast.LENGTH_SHORT).show();
Log.d("Bingo", "onItemSelected");
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
Toast.makeText(getActivity(), "Bingo Nothing", Toast.LENGTH_SHORT).show();
Log.d("Bingo", "onNothingSelected");
}
}
Now, the problem is that when Im trying to select something from Spinner drop down, nothing is selected, OnItemSelected event is not fired at all.
The same code is working fine, when FragmentContainer is moved out from my custom ViewGroup.
Why that happening ??? How can I get Spinner working fine in custom view group ??

Answer 1

Second Edit --------------
I had a problem very similar to yours. (See the original post below for more detail.) Without knowing more about your custom ViewGroup implementation I don't know whether my solution will work for you or not.
My problem turned out to be that in my "layoutChildren" implementation I introduced an "optimization" whereby if I was reusing a child view whose content I knew hadn't changed (and the layout window hadn't changed either) I didn't bother to remeasure the child view.
It turns out if you're using Spinners you can't get away with this. The reason has to do with the convoluted way certain View.mPrivateFlags (PFLAGS_FORCE_LAYOUT and PFLAGS_LAYOUT_REQUIRED) are implemented relative to tracking the need to reprocess the layout of a child view IN COMBINATION WITH the way the Spinner decides to trigger the onItemSelected listener.
As noted below, Spinner fires the onItemSelected listener when it is asked to perform a layout and therein recognizes that the selected item has changed. If it doesn't perform a layout, it knows (internally) that the selected item has changed, but doesn't call the onItemSelected listener.
From the Spinner's perspective this is ok, because when the Spinner saw the new item selected, it specifically requested a layout pass (requestLayout).
The layout pass begins and propagates down to my custom ViewGroup. When it gets to the first child that child has its PFLAGS_FORCE_LAYOUT bit set...but that flag is ignored by the processing logic. Instead it is looking only for the PFLAGS_LAYOUT_REQUIRED bit, and when it doesn't see that flag it decides it is not necessary to propagate the layout any further down the view hierarchy, and so the Spinner never gets asked to perform a layout and never fires the onItemSelected listener.
The fix was to remove the optimization to not measure child views whose dimensions are already known. PFLAGS_LAYOUT_REQUIRED (which is package private...you can't get to it from anything you write) only gets set when the child views are asked to measure themselves, and even though the measurement itself was not strictly necessary in my case, it is the only way to get the mPrivateFlags manipulated into the correct state.
Check to be sure you are measuring your child views (particularly views that are being re-used from prior layout passes) and see if this addresses your problem.
First Edit ---------------
I've made some progress on this, but still haven't solved it. The Spinner calls the onItemSelected listener when its onLayout() method is called and it recognizes that the selected item has changed.
When the Spinner is hosted by a ListView, the ListView.onLayout(...) gets called after the selection in the Spinner is changed (though I haven't been able to figure out how), and the ListView onLayout method propagates that call down to the Spinner, resulting in an onItemSelected() call.
When the Spinner is hosted by my custom AdapterView, the onLayout method never gets called after the Spinner is changed, and so no onItemSelected() call is made.
I just haven't yet been able to figure out why, where, or how, a layout request is being triggered in the one case but not in the other. Because the layout request is posted to the message queue and executed from there, it is very difficult to determine where it originated.
Let me know if this helps you any, or gives you any ideas.
Original Post ------------
I'm having the same problem. I created a custom ViewGroup (extended AdapterView) and now child views that include spinners don't fire the onItemSelected listener. If I attach the same child view to a ListView (also extended from AdapterView) it works fine. I did something wrong in my custom ViewGroup, but I know not what.
Did you find a solution to your problem? If so, can you post it?

Answer 2

This post is very old but it helped me tremendously - though I STILL had the problem (though every OTHER time I selected something from the dropdown - rather than every time).
If it helps - the fix for my issue was to NOT call bringToFront on the spinner object that was displaying the problem.

Answer 3

As Steve has pointed out already, the problem is that certain flags need to be manipulated to actually force a layout, and the only (public) way to do so is to call measure()...
As a workaround, adding the following method to my custom ViewGroup addressed the problem for me, but you might want to make sure not to make too many extra/redundant measurements, depending on the actual use case...
public void requestLayout() {
super.requestLayout();
measure(MeasureSpec.EXACTLY | getMeasuredWidth(),
MeasureSpec.EXACTLY | getMeasuredHeight());
}
Minimal code snippet reproducing the problem:
package org.kobjects.spinnertestapp;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import java.util.ArrayList;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ArrayList<String> options = new ArrayList<>();
options.add("Hello");
options.add("Wutan");
options.add("Lorem Ipsum");
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this,android.R.layout.simple_spinner_dropdown_item, options);
Spinner spinner = new Spinner(this);
spinner.setAdapter(arrayAdapter);
MyLayout layout = new MyLayout(this);
layout.addView(spinner);
setContentView(layout);
}
static class MyLayout extends ViewGroup {
public MyLayout(Context context) {
super(context);
}
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
for (int i = 0; i < getChildCount(); i ++) {
getChildAt(i).layout(left, top, right, bottom);
}
}
}
}