What is the correct way to implement a GridViewPager on Android Wear?

Question

I'm trying to implement a GridViewPager so I can switch between 2 unique views. So far I haven't been able to add any views at all. Below is my code ``` public class Gridder extends Activity { private TextView mTextView; GridViewPager gridViewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_gridder); final WatchViewStub stub = (WatchViewStub) findViewById(R.id.watch_view_stub); final LayoutInflater inflater = getLayoutInflater(); stub.setOnLayoutInflatedListener(new WatchViewStub.OnLayoutInflatedListener() { @Override public void onLayoutInflated(WatchViewStub stub) { gridViewPager = (GridViewPager) findViewById(R.id.pager); gridViewPager.setAdapter(new MyGridViewPagerAdapter()); gridViewPager.addView(inflater.inflate(R.layout.selector_generic, stub));; } }); } private class MyGridViewPagerAdapter extends GridPagerAdapter { @Override protected void destroyItem(ViewGroup arg0, int arg1, int arg2,…

Accepted Answer

Stacktrace explanation: First of all - the following line is wrong: ``` gridViewPager.addView(inflater.inflate(R.layout.selector_generic, stub)); ``` `inflate(int resource, ViewGroup root)` with `root!=null` is the same as `inflate(int resource, ViewGroup root, boolean attachToRoot)` with last argument as `true`. So according to the documentation it will inflate view from `resource` and attach it to root -> then return a root. this will try to attach newly inflated view to `stub`, and then try to attach `stub` (result from `inflate()` with specified `root`) to the `gridViewPager`. But `stub` already has a parent (it's already attached to the view hierarchy in your activity). So this is an explanation of stacktrace:) Please note that you should NOT add views to `gridViewPager` via `.addView()` methods - you should do it via adapter instead and that line should be removed. GridPagerAdapter example: Here is simple implementation for `GridPagerAdapter`; ``` private class MyGridViewPagerAdapter extends GridPagerAdapter { @Override public int getColumnCount(int arg0) { return 2; } @Override public int getRowCount() { return 2; } @Override protected Object instantiateItem(ViewGroup container, int row, int col) { final View view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.grid_view_pager_item, container, false); final TextView textView = (TextView) view.findViewById(R.id.textView); textView.setText(String.format("Page: %1$s, %2$s", row, col)); container.addView(view); return view; } @Override protected void destroyItem(ViewGroup container, int row, int col, Object view) { container.removeView((View)view); } @Override public boolean isViewFromObject(View view, Object object) { return view==object; } } ``` Content of `grid_view_pager_item.xml`: ``` ``` Here is a final result of 2x2 grid. Two screens are in still state and two are pictured during the pages being half-scrolled:) Looking for more? This is just an example of using standard `GridPagerAdapter`. If you want more advanced one, with usage of `FragmentGridPagerAdapter`, `CardFragments` and pages backgrounds - please see the `GridViewPager` example located in platform samples: `{sdk_root}/samples/android-20/wearable/GridViewPager`

What is the correct way to implement a GridViewPager on Android Wear?

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