两种保存状态的方法getSharedPreferences和onSaveInstanceState

虽然这些东西很简单有时候还真的让你搞混

@Override 
protected void onPause() { 
    super.onPause(); 
 
    SharedPreferences prefs = getSharedPreferences("X", MODE_PRIVATE); 
    Editor editor = prefs.edit(); 
    editor.putString("lastActivity", getClass().getName()); 
    editor.commit(); 
} 
public class Dispatcher extends Activity { 
 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
 
        Class<?> activityClass; 
 
        try { 
            SharedPreferences prefs = getSharedPreferences("X", MODE_PRIVATE); 
            activityClass = Class.forName( 
                prefs.getString("lastActivity", Activity1.class.getName())); 
        } catch(ClassNotFoundException ex) { 
            activityClass = Activity1.class; 
        } 
 
        startActivity(new Intent(this, activityClass)); 
    } 
} 
上面的方法通常保存一个activity以便下次发动

2.

@Override 
public void onSaveInstanceState(Bundle savedInstanceState) { 
  // Save UI state changes to the savedInstanceState. 
  // This bundle will be passed to onCreate if the process is 
  // killed and restarted. 
  savedInstanceState.putBoolean("MyBoolean", true); 
  savedInstanceState.putDouble("myDouble", 1.9); 
  savedInstanceState.putInt("MyInt", 1); 
  savedInstanceState.putString("MyString", "Welcome back to Android"); 
  // etc. 
  super.onSaveInstanceState(savedInstanceState); 
} 
@Override 
public void onRestoreInstanceState(Bundle savedInstanceState) { 
  super.onRestoreInstanceState(savedInstanceState); 
  // Restore UI state from the savedInstanceState. 
  // This bundle has also been passed to onCreate. 
  boolean myBoolean = savedInstanceState.getBoolean("MyBoolean"); 
  double myDouble = savedInstanceState.getDouble("myDouble"); 
  int myInt = savedInstanceState.getInt("MyInt"); 
  String myString = savedInstanceState.getString("MyString"); 
} 

这个上次已经记过了用来旋转保存状态最好