onCreate中的savedInstanceState有何具體作用？具體例子？

在activity的生命周期中，只要離開了可見階段，或者說失去了焦點，activity就很可能被進程終止了！，被KILL掉了，，這時候，就需要有種機制，能保存當時的狀態，這就是savedInstanceState的作用。

當一個Activity在PAUSE時，被kill之前，它可以調用onSaveInstanceState()來保存當前activity的狀態信息（在paused狀態時，要被KILLED的時候）。用來保存狀態信息的Bundle會同時傳給兩個method,即onRestoreInstanceState() and onCreate().

示例代碼如下：

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);

    }

}