返回上一个活动的最后状态

Question

I have two activities A and B. When the application starts, activity A is loaded and I load data to it from database. I can go to activity B without any problems, but when I go back to activity A, the old data are viewed for a moment and the activity is reloaded.

Any idea how to fix this?

Answer 1

在从DB开始加载数据之前，清除所有字段。从加载数据开始花费的时间很少，并且在清除之前的字段之前。

Answer 2

Here You can put all field as blank..

You need to override onSaveInstanceState(Bundle savedInstanceState) and write the application activity state values you want to change to the Bundle parameter like this:

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
  super.onSaveInstanceState(savedInstanceState);
  /* Save UI state changes to the savedInstanceState.
  * This bundle will be passed to onCreate if the process is
  * killed and restarted activity
  */
  savedInstanceState.putString("YourString", "");

  // etc...
  // etc...
}

The Bundle is essentially a way of storing a NVP ("Name-Value Pair") map, and it will get passed in to onCreate() and also onRestoreInstanceState() where you'd extract the values like this:

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
  super.onRestoreInstanceState(savedInstanceState);
  // Restore UI state from the savedInstanceState.
  // This bundle has also been passed to onCreate.

  String myString = savedInstanceState.getString("YourString");
}

You would usually use this technique to store instance values for your application (selections, unsaved text) etc.