Created
April 7, 2014 10:23
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import android.os.Bundle; | |
import android.os.Handler; | |
import android.support.v4.app.ListFragment; | |
import android.view.View; | |
import android.widget.AbsListView; | |
public class FrozenListFragment extends ListFragment { | |
private static final String ARG_Y = "y"; | |
private static final String ARG_POSITION = "position"; | |
private int position = -1; | |
private int y = 0; | |
private Handler mHandler = new Handler(); | |
@Override | |
public void onCreate(Bundle savedInstanceState) { | |
super.onCreate(savedInstanceState); | |
restoreStateFromBundle(savedInstanceState); | |
} | |
@Override | |
public void onViewCreated(View view, Bundle savedInstanceState) { | |
super.onViewCreated(view, savedInstanceState); | |
getListView().setOnScrollListener(new AbsListView.OnScrollListener() { | |
@Override | |
public void onScrollStateChanged(AbsListView view, int scrollState) { | |
if (scrollState == SCROLL_STATE_IDLE) { | |
storeListPosition(view); | |
} | |
} | |
@Override | |
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { | |
} | |
}); | |
} | |
@Override | |
public void onViewStateRestored(Bundle savedInstanceState) { | |
super.onViewStateRestored(savedInstanceState); | |
restoreStateFromBundle(savedInstanceState); | |
} | |
private void restoreStateFromBundle(Bundle savedInstanceState) { | |
if (savedInstanceState != null) { | |
position = savedInstanceState.getInt(ARG_POSITION); | |
y = savedInstanceState.getInt(ARG_Y); | |
} | |
} | |
@Override | |
public void onSaveInstanceState(Bundle outState) { | |
super.onSaveInstanceState(outState); | |
outState.putInt(ARG_POSITION, position); | |
outState.putInt(ARG_Y, y); | |
} | |
@Override | |
public void onResume() { | |
super.onResume(); | |
restoreListPosition(); | |
} | |
private void storeListPosition(AbsListView listView) { | |
position = listView.getFirstVisiblePosition(); | |
View v = listView.getChildAt(0); | |
y = (v == null) ? 0 : v.getTop(); | |
} | |
public void restoreListPosition() { | |
if (position >= 0) { | |
mHandler.post(new Runnable() { | |
@Override | |
public void run() { | |
if (getView() != null) { | |
getListView().setSelectionFromTop(position, y); | |
} | |
} | |
}); | |
} | |
} | |
} |
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