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最近在查看OnCreate(saveInstanceState)時候，只懂得其中是為了儲存當activity失去焦點的時候的狀態，卻不知其實如何?的，今天發現一個好文章，和大家分享一下哦。
在activity的生命週期中，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，能儲存當時的狀態，這就是savedInstanceState的作用。 當一個Activity在PAUSE時，被kill之前，它可以調用onSaveInstanceState()來儲存當前activity的狀態資訊。用來儲存狀態資訊的Bundle會同時傳給兩個method,即onRestoreInstanceState() and onCreate(). 範例程式碼如下：
- 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);
- }
- }
onCreate中的savedInstanceState有何具體作用
