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);    }}