zoukankan      html  css  js  c++  java
  • Android onCreate 的savedInstanceState 作用

    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

  • 相关阅读:
    vscode设置不展示 .pyc文件
    Centos7安装python3并与python2共存, 以及安装pip(pip3)
    vmware 安装 centos7 及网络配置,永久修改主机名
    VMware虚拟机ubuntu显示屏幕太小解决办法, 安装 VM tools
    struct timeval和gettimeofday()
    cocos2d-x中CCLabelAtlas的小图片拼接
    Core Animation系列之CADisplayLink
    Xcode5 上64位编译 出错No architectures to compile for
    通过OpenGL ES在iOS平台实践增强现实
    通过OpenGL ES在iOS平台实践增强现实(一)
  • 原文地址:https://www.cnblogs.com/jasonkent27/p/4212243.html
Copyright © 2011-2022 走看看