Android(安卓)Activity 生命周期全解析
Activity作为Android的四大组件之一,在实际开发中扮演着很重要的角色,了解它的声明周期对我们以后的开发会很有帮助,下面我们来看看在不同场景下Activity的生命周期
准备两个Activity,IndexActivity和TwoActivity
public class IndexActivity extends AppCompatActivity { public static final String TAG = "IndexActivity"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); findViewById(R.id.text_request_one).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { startActivity(new Intent(IndexActivity.this, TwoActivity.class)); } }); Log.i(TAG, "onCreate"); } @Override protected void onStart() { super.onStart(); Log.i(TAG, "onStart"); } @Override protected void onRestart() { super.onRestart(); Log.i(TAG, "onRestart"); } @Override protected void onResume() { super.onResume(); Log.i(TAG, "onResume"); } @Override protected void onPause() { super.onPause(); Log.i(TAG, "onPause"); } @Override protected void onStop() { super.onStop(); Log.i(TAG, "onStop"); } @Override protected void onDestroy() { super.onDestroy(); Log.i(TAG, "onDestroy"); } @Override protected void onNewIntent(Intent intent) { super.onNewIntent(intent); Log.i(TAG, "onNewIntent"); }}public class TwoActivity extends AppCompatActivity { public static final String TAG = "TwoActivity"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Log.i(TAG, "onCreate"); } @Override protected void onStart() { super.onStart(); Log.i(TAG, "onStart"); } @Override protected void onRestart() { super.onRestart(); Log.i(TAG, "onRestart"); } @Override protected void onResume() { super.onResume(); Log.i(TAG, "onResume"); } @Override protected void onPause() { super.onPause(); Log.i(TAG, "onPause"); } @Override protected void onStop() { super.onStop(); Log.i(TAG, "onStop"); } @Override protected void onDestroy() { super.onDestroy(); Log.i(TAG, "onDestroy"); }}
启动App IndexActivity的生命周期
01-22 15:44:02.131 23541-23541/fe.dotwoven I/IndexActivity: onCreate01-22 15:44:02.131 23541-23541/fe.dotwoven I/IndexActivity: onStart01-22 15:44:02.133 23541-23541/fe.dotwoven I/IndexActivity: onResume
启动IndexActivity分别调用了onCreate,onStart, onResume方法。
按Home键回到桌面 Activity生命周期
01-22 15:46:52.583 23541-23541/fe.dotwoven I/IndexActivity: onPause01-22 15:46:53.110 23541-23541/fe.dotwoven I/IndexActivity: onStop
回到桌面会调用IndexActivity的onPause,onStop方法
从桌面再次进入IndexActivity 生命周期
01-22 15:47:51.388 23541-23541/fe.dotwoven I/IndexActivity: onRestart01-22 15:47:51.388 23541-23541/fe.dotwoven I/IndexActivity: onStart01-22 15:47:51.388 23541-23541/fe.dotwoven I/IndexActivity: onResume
再次进入的时候调用了IndexActivity的onRestart,onStart,onResume方法
IndexActivity上按返回键时生命周期
01-22 15:50:03.004 23541-23541/fe.dotwoven I/IndexActivity: onPause01-22 15:50:03.558 23541-23541/fe.dotwoven I/IndexActivity: onStop01-22 15:50:03.558 23541-23541/fe.dotwoven I/IndexActivity: onDestroy
分别执行了IndexActivity的onPause,onStop,onDestroy方法
从IndexActivity跳转到TwoActivity生命周期
01-22 15:51:54.183 23541-23541/fe.dotwoven I/IndexActivity: onPause01-22 15:51:54.270 23541-23541/fe.dotwoven I/TwoActivity: onCreate01-22 15:51:54.271 23541-23541/fe.dotwoven I/TwoActivity: onStart01-22 15:51:54.273 23541-23541/fe.dotwoven I/TwoActivity: onResume01-22 15:51:54.688 23541-23541/fe.dotwoven I/IndexActivity: onStop
首先会执行IndexActivity的onPause方法,接下来执行TwoActivity的onCreate,onStart,onResume方法;最后才会执行IndexActivity的onStop方法,最后这点大家要记住
TwoActivity按返回键返回IndexActivity生命周期
01-22 15:53:49.444 23541-23541/fe.dotwoven I/TwoActivity: onPause01-22 15:53:49.484 23541-23541/fe.dotwoven I/IndexActivity: onRestart01-22 15:53:49.485 23541-23541/fe.dotwoven I/IndexActivity: onStart01-22 15:53:49.494 23541-23541/fe.dotwoven I/IndexActivity: onResume01-22 15:53:49.870 23541-23541/fe.dotwoven I/TwoActivity: onStop01-22 15:53:49.870 23541-23541/fe.dotwoven I/TwoActivity: onDestroy
首先会执行TwoActivity的onPause方法,接下来调用IndexActivity的onRestart,onStart,onResume方法,最后再调用TwoActivity的onStop和onDestroy方法。
启动模式不同 Activity的生命周期
如果IndexActivity的启动模式是singleTask或是singleInstance,然后从IndexActivity跳转到TwoActivity,再从TwoActivity跳转到IndexActivity,这个时候生命周期会有什么不同呢?我们来看看
01-22 16:07:53.739 18403-18403/fe.dotwoven I/TwoActivity: onPause01-22 16:07:53.762 18403-18403/fe.dotwoven I/IndexActivity: onNewIntent01-22 16:07:53.762 18403-18403/fe.dotwoven I/IndexActivity: onRestart01-22 16:07:53.765 18403-18403/fe.dotwoven I/IndexActivity: onStart01-22 16:07:53.767 18403-18403/fe.dotwoven I/IndexActivity: onResume01-22 16:07:54.103 18403-18403/fe.dotwoven I/TwoActivity: onStop01-22 16:07:54.103 18403-18403/fe.dotwoven I/TwoActivity: onDestroy
IndexActivity多调用了一个onNewIntent方法。
如果IndexActivity的启动模式是singleTop,然后从IndexActivity启动到IndexActivity,它其实显示的还是IndexActivity,那IndexActivity的生命周期会有什么不同呢?
01-22 16:13:03.392 4830-4830/fe.dotwoven I/IndexActivity: onPause01-22 16:13:03.392 4830-4830/fe.dotwoven I/IndexActivity: onNewIntent01-22 16:13:03.393 4830-4830/fe.dotwoven I/IndexActivity: onResume
可以看到它先调用了自己的onPause方法,然后调用了onNewIntent,onResume方法。
总结
到此Activity各个场景的生命周期差不多都分析完了,理解好Activity的生命周期有利于我们的开发工作
更多相关文章
- Android中OptionMenu使用
- android resoult A>B 结束B A显示B中的内容
- Android读取本地json文件的方法(解决显示乱码问题)
- Android中Dialog设置外部点击事件
- android的TabActivity
- Android(安卓)TextSwitcher(文字交换器)的使用
- 总结Android中的Info系列类
- Android中的onActivityResult和setResult方法的使用
- Android(安卓)关于ObjectAnimator 的几种状态