Android 4.2: Backstack-Verhalten mit verschachtelten Fragmenten
Mit Android 4.2 wurde die Support-Bibliothek für verschachtelte Fragmente unterstütztsiehe hier. Ich habe damit herumgespielt und ein interessantes Verhalten / einen Fehler in Bezug auf Backstack und gefundengetChildFragmentManager (). Wenn Sie getChildFragmentManager () und addToBackStack (String name) verwenden und die Zurück-Taste drücken, wird der Stapel nicht bis zum vorherigen Fragment heruntergefahren. Auf der anderen Seite bei der VerwendunggetFragmentManager () und addToBackStack (String name) kehrt das System durch Drücken der Zurück-Taste zum vorherigen Fragment zurück.
Für mich ist dieses Verhalten unerwartet. Durch Drücken der Zurück-Taste auf meinem Gerät erwarte ich, dass das zuletzt hinzugefügte Fragment auf dem Hintergrundstapel abgelegt wird, auch wenn das Fragment im Fragment-Manager der Kinder zum Hintergrundstapel hinzugefügt wurde.
Ist dieses Verhalten korrekt? Ist dieses Verhalten ein Fehler? Gibt es eine Lösung für dieses Problem?
Beispielcode mit getChildFragmentManager ():public class FragmentceptionActivity extends FragmentActivity {
@Override
protected void onCreate(Bundle arg0) {
super.onCreate(arg0);
final FrameLayout wrapper1 = new FrameLayout(this);
wrapper1.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper1.setId(1);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 0;
final TextView text = new TextView(this);
text.setLayoutParams(params);
text.setText("fragment 1");
wrapper1.addView(text);
setContentView(wrapper1);
getSupportFragmentManager().beginTransaction().addToBackStack(null)
.add(1, new Fragment1()).commit();
}
public class Fragment1 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper2 = new FrameLayout(getActivity());
wrapper2.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper2.setId(2);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 100;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 2");
wrapper2.addView(text);
return wrapper2;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getFragmentManager().beginTransaction().addToBackStack(null)
.add(2, new Fragment2()).commit();
}
}
public class Fragment2 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper3 = new FrameLayout(getActivity());
wrapper3.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper3.setId(3);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 200;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 3");
wrapper3.addView(text);
return wrapper3;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getChildFragmentManager().beginTransaction().addToBackStack(null)
.add(3, new Fragment3()).commit();
}
}
public class Fragment3 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper4 = new FrameLayout(getActivity());
wrapper4.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper4.setId(4);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 300;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 4");
wrapper4.addView(text);
return wrapper4;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getChildFragmentManager().beginTransaction().addToBackStack(null)
.add(4, new Fragment4()).commit();
}
}
public class Fragment4 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper5 = new FrameLayout(getActivity());
wrapper5.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper5.setId(5);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 400;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 5");
wrapper5.addView(text);
return wrapper5;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
}
}
public class FragmentceptionActivity extends FragmentActivity {
@Override
protected void onCreate(Bundle arg0) {
super.onCreate(arg0);
final FrameLayout wrapper1 = new FrameLayout(this);
wrapper1.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper1.setId(1);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 0;
final TextView text = new TextView(this);
text.setLayoutParams(params);
text.setText("fragment 1");
wrapper1.addView(text);
setContentView(wrapper1);
getSupportFragmentManager().beginTransaction().addToBackStack(null)
.add(1, new Fragment1()).commit();
}
public class Fragment1 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper2 = new FrameLayout(getActivity());
wrapper2.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper2.setId(2);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 100;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 2");
wrapper2.addView(text);
return wrapper2;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getFragmentManager().beginTransaction().addToBackStack(null)
.add(2, new Fragment2()).commit();
}
}
public class Fragment2 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper3 = new FrameLayout(getActivity());
wrapper3.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper3.setId(3);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 200;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 3");
wrapper3.addView(text);
return wrapper3;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getFragmentManager().beginTransaction().addToBackStack(null)
.add(3, new Fragment3()).commit();
}
}
public class Fragment3 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper4 = new FrameLayout(getActivity());
wrapper4.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper4.setId(4);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 300;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 4");
wrapper4.addView(text);
return wrapper4;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getFragmentManager().beginTransaction().addToBackStack(null)
.add(4, new Fragment4()).commit();
}
}
public class Fragment4 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final FrameLayout wrapper5 = new FrameLayout(getActivity());
wrapper5.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.MATCH_PARENT));
wrapper5.setId(5);
final FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.topMargin = 400;
final TextView text = new TextView(getActivity());
text.setLayoutParams(params);
text.setText("fragment 5");
wrapper5.addView(text);
return wrapper5;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
}
}