My app exits when i try to move from child fragment to parent fragment(it doesn't crashes).Here LandingActivity.java is main activity in which I am calling fragment ChannelGrid.java which calls fragment GridMain.java.When i presses back button of mobile in fragment GridMain app exits rather than moving to ChannelGrid.java.I have added addToBackStack("tag") to fragments and also tried using onKey()..I tested my app on different devices also..I checked out other solutions with same issue and tried them but nothing works..
Navigation Drawer-LandingActivity.java-ChaanelGrid.java(Fragment)-GridMain.java(Fragment)
LandingActivity.java
currentFragment = new ChaanelGrid();
currentFragment.setArguments(args);
frgManager = getFragmentManager();
frgManager.beginTransaction().add(R.id.content_frame, currentFragment).addToBackStack("tag")
.commit();
ChaanelGrid.java
Fragment currentFragment = new GridMain();
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().add(R.id.content_frame, currentFragment).addToBackStack("GridMain")
.commit()
GridMain.java(i tried without onKey() method also but didn't worked)
rootView.setOnKeyListener(new View.OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK)
{
Fragment currentFragment = new ChaanelGrid();
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().replace(R.id.content_frame, currentFragment)
.commit();
return true;
}
logcat verbose
10-31 21:46:57.954 24452-24452/D/ActivityThread﹕ ACT-AM_ON_PAUSE_CALLED ActivityRecord{41eb8b98 token=android.os.BinderProxy@41bb9828 {xyz/xyz..activity.LandingActivity_}}
10-31 21:46:57.971 24452-24452/ D/ActivityThread﹕ ACT-PAUSE_ACTIVITY_FINISHING handled : 0 / android.os.BinderProxy@41bb9828
10-31 21:46:58.007 24452-24452/ V/InputMethodManager﹕ focusOut: android.widget.GridView@41f06f40 mServedView=android.widget.GridView@41f06f40 winFocus=false
10-31 21:46:58.297 24452-24452/ I/SurfaceTextureClient﹕ [0x5143bc58] frames:44, duration:1.002000, fps:43.883736
10-31 21:46:58.350 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.432 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.753 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.754 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 0)
10-31 21:46:58.755 24452-24452/ D/OpenGLRenderer﹕ Flushing caches (mode 2)
10-31 21:46:58.879 24452-24452/ D/ActivityThread﹕ ACT-DESTROY_ACTIVITY handled : 1 / android.os.BinderProxy@41bb9828
I tried adding following in LandingActivity.java
@Override
public void onBackPressed() {
FragmentManager frgManager;
frgManager = getFragmentManager();
Fragment fragment = fragmentManager.findFragmentByTag("GridMain");
if (fragment != null) {
GridMain gridMain = (GridMain) fragment;
if (!gridMain.onBackPressed()) {
super.onBackPressed();
}
}
else {
super.onBackPressed();
}
}
and following in GridMain.java
protected boolean onBackPressed() {
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.popBackStack();
return true;
}
Using Log i checked tht onBackPressed() of LandingActivity.java is being called but still the same output..
This is how I normally handle the Back Button:
// "State Machine" variables: to indicate which is the active Fragment.
private static boolean isHelpShown = false;
protected static boolean isInfoShown = false;
protected static boolean isMainShown = false;
private static boolean isViewShown = false;
// Used to switch between Fragments.
private static enum Fragments
{
MAIN,
VIEW,
HELP,
INFO
}
@Override
public final void onBackPressed()
{
if (isMainShown)
{
// We're in the MAIN Fragment.
finish();
}
else
{
// We're somewhere else, reload the MAIN Fragment.
showFragment(Fragments.MAIN);
}
}
private final void showFragment(final Fragments FragmentType)
{
isViewShown = false;
isHelpShown = false;
isInfoShown = false;
isMainShown = false;
final FragmentTransaction ft =
getSupportFragmentManager().beginTransaction();
/*
Replace whatever is in the fragment_container view with this
fragment, and add the transaction to the back stack so the user can
navigate back.
*/
switch(FragmentType)
{
case HELP:
{
ft.replace(R.id.frgMaster, new FRG_Help());
isHelpShown = true;
break;
}
case INFO:
{
ft.replace(R.id.frgMaster, new FRG_Info());
isInfoShown = true;
break;
}
case VIEW:
{
ft.replace(R.id.frgMaster, new FRG_View());
isViewShown = true;
break;
}
case MAIN:
{
ft.replace(R.id.frgMaster, new FRG_Main());
isMainShown = true;
break;
}
}
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
// Finalize the transaction...
ft.commit();
getSupportFragmentManager().executePendingTransactions();
}
As you can see, for my needs I only handle when we're in the MAIN Fragment (I quit) or when we aren't (I go back to the MAIN Fragment: another Back press and it quits).
You can add more checks in the onBackPressed method to check if you are in another Fragment and load another one, accordingly.