只是片段与savedInstanceState保存在默认情况下？

问题描述

我读了
这给人的onSaveInstanceState你应用程序的previous状态的包（如果屏幕的方向改变。

I read on What's onCreate(Bundle savedInstanceState)that onsaveinstancestate gives you a bundle of the previous state of the application(if the orientation of the screen changed.

我看着在Android文档（），看到你必须手动将您需要保存为键值对的值。他们的code，这样做是

I looked on the Android docs(http://developer.android.com/training/basics/activity-lifecycle/recreating.html) and saw that you have to manually put the values you want saved as key value pairs. Their code for doing so was

    static final String STATE_SCORE = "playerScore";
static final String STATE_LEVEL = "playerLevel";
...

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    // Save the user's current game state
    savedInstanceState.putInt(STATE_SCORE, mCurrentScore);
    savedInstanceState.putInt(STATE_LEVEL, mCurrentLevel);

我的问题是碎片，当方向改变和重建活动他们在自动重新连接？你必须把code将其保存为一个束？
Facebook的继承人code针对这种情况，我想了解

My question is for fragments, are they automatically reattached when the orientation changes and the activity recreated? Would you have to put code to save it into a bundle?Heres facebook code for this situation that I am trying to understand

 @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

if (savedInstanceState == null) {
    // Add the fragment on initial activity setup
    mainFragment = new MainFragment();
    getSupportFragmentManager()
    .beginTransaction()
    .add(android.R.id.content, mainFragment)
    .commit();
} else {
    // Or set the fragment from restored state info
    mainFragment = (MainFragment) getSupportFragmentManager()
    .findFragmentById(android.R.id.content);
}

}

推荐答案

要保持一个片段，当活动被破坏，所以它会自动reataches，你应该叫

To keep a fragment when an Activity gets destroyed, so it automatically reataches, you should call

Fragment.setRetainInstance(true)

在片段的构造。
没有默认情况下，在保存的onSaveInstanceState（）

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