I don't understand why onDestroy is being logged twice for the fragment claass in the the following code when the orientation of the device changes. Can someone explain to me what I am doing wrong?
public class ExampleActivity extends Activity {
protected String LOG_TAG = ExampleActivity.class.getSimpleName();
private FrameLayout mFragmentHolder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LogUtil.i(LOG_TAG, "onCreate");
setContentView(R.layout.activity_main);
mFragmentHolder = (FrameLayout) findViewById(R.id.root);
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(mFragmentHolder.getId(),MyFragment.newInstance());
ft.commit();
}
@Override
protected void onDestroy() {
super.onDestroy();
LogUtil.i(LOG_TAG, "onDestroy");
}
@Override
protected void onPause() {
super.onPause();
LogUtil.i(LOG_TAG, "onPause");
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
LogUtil.i(LOG_TAG, "onRestoreInstanceState");
}
@Override
protected void onResume() {
super.onResume();
LogUtil.i(LOG_TAG, "onResume");
}
@Override
protected void onStart() {
super.onStart();
LogUtil.i(LOG_TAG, "onStart");
}
@Override
protected void onStop() {
super.onStop();
LogUtil.i(LOG_TAG, "onStop");
}
}
And here is the fragment is the fragment class
public class MyFragment extends Fragment {
protected String LOG_TAG = MyFragment.class.getSimpleName();
public static Fragment newInstance(){
return new MyFragment();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.screen_login, container,
false);
return view;
}
@Override
public void onDestroy() {
super.onDestroy();
LogUtil.i(LOG_TAG, "onDestroy");
}
@Override
public void onPause() {
super.onPause();
LogUtil.i(LOG_TAG, "onPause");
}
@Override
public void onResume() {
super.onResume();
LogUtil.i(LOG_TAG, "onResume");
}
@Override
public void onStart() {
super.onStart();
LogUtil.i(LOG_TAG, "onStart");
}
@Override
public void onStop() {
super.onStop();
LogUtil.i(LOG_TAG, "onStop");
}
}
And here is the output from logcat
01-17 22:04:34.661: I/BaseApplication(21513): [0.0.7]-[BaseApplication]-[main]-[01/17/2014 22:04:34] onConfigurationChanged
01-17 22:04:34.706: I/MyFragment(21513): [0.0.7]-[MyFragment]-[main]-[01/17/2014 22:04:34] onPause
01-17 22:04:34.711: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onPause
01-17 22:04:34.721: I/MyFragment(21513): [0.0.7]-[MyFragment]-[main]-[01/17/2014 22:04:34] onStop
01-17 22:04:34.726: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onStop
01-17 22:04:34.731: I/MyFragment(21513): [0.0.7]-[MyFragment]-[main]-[01/17/2014 22:04:34] onDestroy
01-17 22:04:34.736: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onDestroy
01-17 22:04:34.766: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onCreate
01-17 22:04:34.866: I/MyFragment(21513): [0.0.7]-[MyFragment]-[main]-[01/17/2014 22:04:34] onDestroy
01-17 22:04:34.876: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onStart
01-17 22:04:34.881: I/MyFragment(21513): [0.0.7]-[MyFragment]-[main]-[01/17/2014 22:04:34] onStart
01-17 22:04:34.886: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onRestoreInstanceState
01-17 22:04:34.891: I/ExampleActivity(21513): [0.0.7]-[ExampleActivity]-[main]-[01/17/2014 22:04:34] onResume
01-17 22:04:34.896: I/MyFragment(21513): [0.0.7]-[MyFragment]-[main]-[01/17/2014 22:04:34] onResume
It seems that using FragmentActivity
from the support library saves and restores instance automatically. Therefore, only do your fragment transactions if savedInstanceState
is null
.
For example, in your FragmentActivity
's onCreate()
, do the following:
if(savedInstanceState == null){
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.fragment_container, mFragment).commit(); //mFragment is your own defined fragment
}
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