Activity、Fragment状态缓存和恢复

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资料

Activity/Fragment状态缓存和恢复的最佳实践
译文

总结

Activity

Activity中已经自己实现了。
只要重写onSaveInstanceState()和onRestoreInstanceState()这两个方法即可

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protected void onSaveInstanceState(Bundle outState) {
    outState.putString("key", "value");
    super.onSaveInstanceState(outState);
}

protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    String value = savedInstanceState.getString("key");
    Log.i(TAG, "onRestoreInstanceState: "+value);
}

Fragment

Fragment分为两种：

  • 一种是View的Save/Restore
  • 另一种是Fragment自身数据的Save/Restore

View的Save/Restore

和Activity一样，在View内部实现onSaveInstanceState()和onRestoreInstanceState()即可。
如果是第三方的View，则写一个子类手动实现Save/Restore即可。

Fragment的Save/Restore

在Fragment内部实现onSaveInstanceState()和onActivityCreated()即可。

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protected void onSaveInstanceState(Bundle outState) {
    outState.putString("key", "value");
    super.onSaveInstanceState(outState);
}

protected void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    String value = savedInstanceState.getString("key");
    Log.i(TAG, "onRestoreInstanceState: "+value);
}