在activity的生命周期中，只要离开了可见阶段，或者说失去了焦点，activity就很可能被进程终止了！，被KILL掉了，，这时候，就需要有种机制，能保存当时的状态，这就是savedInstanceState的作用。
当一个Activity在PAUSE时，被kill之前，它可以调用onSaveInstanceState()来保存当前activity的状态信息（在paused状态时，要被KILLED的时候）。用来保存状态信息的Bundle会同时传给两个method,即onRestoreInstanceState() and onCreate().
示例代码如下：
package com.myandroid.test;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
public class AndroidTest
extends Activity {
private static final String TAG = "MyNewLog"
;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// If an instance of this activity had previously stopped, we can
// get the original text it started with.
if(
null !=
savedInstanceState)
{
int IntTest = savedInstanceState.getInt("IntTest"
);
String StrTest = savedInstanceState.getString("StrTest"
);
Log.e(TAG, "onCreate get the savedInstanceState+IntTest="+IntTest+"+StrTest="+
StrTest);
}
setContentView(R.layout.main);
Log.e(TAG, "onCreate"
);
}
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save away the original text, so we still have it if the activity
// needs to be killed while paused.
savedInstanceState.putInt("IntTest", 0
);
savedInstanceState.putString("StrTest", "savedInstanceState test"
);
super.onSaveInstanceState(savedInstanceState);
Log.e(TAG, "onSaveInstanceState"
);
}
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
int IntTest = savedInstanceState.getInt("IntTest"
);
String StrTest = savedInstanceState.getString("StrTest"
);
Log.e(TAG, "onRestoreInstanceState+IntTest="+IntTest+"+StrTest="+
StrTest);
}
}
转自：http://blog.csdn.net/xiaoxiao_job/article/details/5852811
转载于:https://www.cnblogs.com/jasonkent27/p/4212243.html
相关资源：savedInstanceState demo
