我在Activity中有一个片段,当旋转设备时,会调用onSaveInstanceState()和onViewStateRestored() .
的onSaveInstanceState():
@Override
public void onSaveInstanceState(Bundle outState){
Log.e("Fragment", "Called onSaveInstanceState");
outState = getSavedInstanceState();
super.onSaveInstanceState(outState);
}
这是在onSaveInstanceState()中设置outState包的原因:
public static Bundle getSavedInstanceState(){
Bundle saveState = new Bundle();
//Save view states
saveState.putBoolean("startButtonVisible", buttonStart.getVisibility() == View.VISIBLE);
saveState.putBoolean("stopButtonVisible", buttonStop.getVisibility() == View.VISIBLE);
saveState.putBoolean("resetButtonVisible", buttonReset.getVisibility() == View.VISIBLE);
saveState.putBoolean("saveButtonVisible", buttonSave.getVisibility() == View.VISIBLE);
saveState.putBoolean("openLatestFileButtonVisible", buttonOpenLatestFile.getVisibility() == View.VISIBLE);
saveState.putBoolean("editTextStartValueVisible", editTextStartValue.isEnabled());
saveState.putBoolean("buttonStartValueDownVisible", buttonStartValueDown.isEnabled());
saveState.putBoolean("buttonStartValueUpVisible", buttonStartValueUp.isEnabled());
saveState.putBoolean("editTextEndValueVisible", editTextEndValue.isEnabled());
saveState.putBoolean("buttonEndValueDownVisible", buttonEndValueDown.isEnabled());
saveState.putBoolean("buttonEndValueUpVisible", buttonEndValueUp.isEnabled());
return saveState;
}
这样可以正确保存数据,但是当调用onViewStateRestored()时,数据不正确 .
@Override
public void onViewStateRestored(Bundle savedInstanceState){
Log.e("Fragment", "Called onViewStateRestored");
super.onViewStateRestored(savedInstanceState);
//Restore view states
if (savedInstanceState != null){
restoreInstanceState(savedInstanceState);
if (buttonReset.getVisibility() == View.VISIBLE){
updateUi();
}
}
}
当调用onViewStateRestored()时,它还调用restoreInstanceState(),这应该是恢复每个视图的状态 .
public static void restoreInstanceState(Bundle savedInstanceState){
buttonStart.setVisibility(savedInstanceState.getBoolean("startButtonVisible") ? View.VISIBLE : View.INVISIBLE);
buttonStop.setVisibility(savedInstanceState.getBoolean("stopButtonVisible") ? View.VISIBLE : View.INVISIBLE);
buttonReset.setVisibility(savedInstanceState.getBoolean("resetButtonVisible") ? View.VISIBLE : View.INVISIBLE);
buttonSave.setVisibility(savedInstanceState.getBoolean("saveButtonVisible") ? View.VISIBLE : View.INVISIBLE);
buttonOpenLatestFile.setVisibility(savedInstanceState.getBoolean("openLatestFileButtonVisible") ? View.VISIBLE : View.INVISIBLE);
editTextStartValue.setEnabled(savedInstanceState.getBoolean("editTextStartValueVisible"));
buttonStartValueDown.setEnabled(savedInstanceState.getBoolean("buttonStartValueDownVisible"));
buttonStartValueDown.setImageResource(buttonStartValueDown.isEnabled() ? R.drawable.ic_arrow_down : R.drawable.ic_arrow_down_gray);
buttonStartValueUp.setEnabled(savedInstanceState.getBoolean("buttonStartValueUpVisible"));
buttonStartValueUp.setImageResource(buttonStartValueUp.isEnabled() ? R.drawable.ic_arrow_up : R.drawable.ic_arrow_up_gray);
editTextEndValue.setEnabled(savedInstanceState.getBoolean("editTextEndValueVisible"));
buttonEndValueDown.setEnabled(savedInstanceState.getBoolean("buttonEndValueDownVisible"));
buttonEndValueDown.setImageResource(buttonEndValueDown.isEnabled() ? R.drawable.ic_arrow_down : R.drawable.ic_arrow_down_gray);
buttonEndValueUp.setEnabled(savedInstanceState.getBoolean("buttonEndValueUpVisible"));
buttonEndValueUp.setImageResource(buttonEndValueUp.isEnabled() ? R.drawable.ic_arrow_up : R.drawable.ic_arrow_up_gray);
Log.e("Fragment", "Restored view visibility");
}
为什么在调用onViewStateRestored()时数据不正确?无论以前是什么,所有的观点都变得无形 . 保存和恢复状态时捆绑包不一样吗?
但是,在调用 fragmentManager.beginTransaction().replace(R.id.content_frame, CustomFragmentManager.savedFilesFragment).commit();
然后手动调用onViewStateRestored()时,所有这些代码都可以正常工作 .
EDIT: 更改了字段名称 .
Solution: 我已将 outState = new Bundle(getSavedInstanceState());
替换为 outState.putAll(getSavedInstanceState());
,现在正在使用 . 不需要调用 setRetainInstance(true);
.
2 回答
我怀疑它与您的方法签名有关 . 你为什么用
static
?静态方法无法访问实例成员 . 这个:应该:
其次,你的字段名称非常类似于Java . 这个:
应该(例如):
First edit
应该早点想到这个 . 由于您只是想保留片段的状态,只需在片段的
onCreate()
中调用setRetainInstance(true)
即可 . 见here .Second edit
另一个回答者是对的:你不应该为out-state创建另一个Bundle . 如果您真的想在单独的方法中创建该Bundle,请改用:
您不应该自己手动创建状态包,使用已在方法onSaveInstanceState()中传递的outState对象并在onCreate()方法中恢复 . 另外,你在你的片段的onCreate()中调用setRetainInstance(true) .