Activity生命周期(二)

1. 什么是生命周期

2. Activity的生命周期函数

3. 生命周期的调用时机

1. 什么是生命周期

类似人的一生

2. Activity的生命周期函数

生命周期函数不是我们来调用的，而是操作系统来管理的

我们能做的就是通过复写函数来完成不同的功能

上帝赐予我们每个人童年青年中年老年

但每二个时间段我们怎么活是我们自己的选择

3. 生命周期的调用时机

采用两个Activity跳转过程的打印内容看出上述几个生命周期函数调用时机

新建class 叫 OtherActivity, 在OtherActivity中复写上述几个生命周期函数

复写OtherActivity.java如下

 1 package first.pack;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.util.Log;
 6 
 7 public class OtherActivity extends Activity {
 8 
 9     @Override
10     protected void onCreate(Bundle savedInstanceState) {
11         super.onCreate(savedInstanceState);
12         Log.i("tag","OtherActivity:OnCreate");
13     }
14 
15     @Override
16     protected void onStart() {
17         super.onStart();
18         Log.i("tag","OtherActivity:OnStart");
19 
20     }
21 
22     @Override
23     protected void onRestart() {
24         super.onRestart();
25         Log.i("tag","OtherActivity:OnRestart");
26 
27     }
28 
29     @Override
30     protected void onResume() {
31         Log.i("tag","OtherActivity:OnResume");
32         super.onResume();
33     }
34 
35     @Override
36     protected void onPause() {
37         Log.i("tag","OtherActivity:OnPause");
38         super.onPause();
39     }
40 
41     @Override
42     protected void onStop() {
43         Log.i("tag","OtherActivity:OnStop");
44         super.onStop();
45     }
46 
47     @Override
48     protected void onDestroy() {
49         Log.i("tag","OtherActivity:OnDestroy");
50         super.onDestroy();
51     }
52 }

类似的，复写MainActivity.java如下

 1 package first.pack;
 2 
 3 import android.support.v7.app.ActionBarActivity;
 4 import android.support.v7.app.ActionBar;
 5 import android.support.v4.app.Fragment;
 6 import android.os.Bundle;
 7 import android.util.Log;
 8 import android.view.LayoutInflater;
 9 import android.view.Menu;
10 import android.view.MenuItem;
11 import android.view.View;
12 import android.view.ViewGroup;
13 import android.os.Build;
14 
15 public class MainActivity extends ActionBarActivity {
16 
17     @Override
18     public void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20         setContentView(R.layout.activity_main);
21 
22         if (savedInstanceState == null) {
23             getSupportFragmentManager().beginTransaction()
24                     .add(R.id.container, new PlaceholderFragment())
25                     .commit();
26         }
27     }
28 
29 
30     @Override
31     public boolean onCreateOptionsMenu(Menu menu) {
32         
33         // Inflate the menu; this adds items to the action bar if it is present.
34         getMenuInflater().inflate(R.menu.main, menu);
35         return true;
36     }
37 
38     @Override
39     public boolean onOptionsItemSelected(MenuItem item) {
40         // Handle action bar item clicks here. The action bar will
41         // automatically handle clicks on the Home/Up button, so long
42         // as you specify a parent activity in AndroidManifest.xml.
43         int id = item.getItemId();
44         if (id == R.id.action_settings) {
45             return true;
46         }
47         return super.onOptionsItemSelected(item);
48     }
49 
50     /**
51      * A placeholder fragment containing a simple view.
52      */
53     public static class PlaceholderFragment extends Fragment {
54 
55         public PlaceholderFragment() {
56         }
57 
58         @Override
59         public View onCreateView(LayoutInflater inflater, ViewGroup container,
60                 Bundle savedInstanceState) {
61             View rootView = inflater.inflate(R.layout.fragment_main, container, false);
62             Log.i("tag","MainActivity:OnCreate");
63             return rootView;
64         }
65         
66         @Override
67         public void onStart() {
68             super.onStart();
69             Log.i("tag","MainActivity:OnStart");
70 
71         }
72 
73         @Override
74         public void onResume() {
75             Log.i("tag","MainActivity:OnResume");
76             super.onResume();
77         }
78 
79         @Override
80         public void onPause() {
81             Log.i("tag","MainActivity:OnPause");
82             super.onPause();
83         }
84 
85         @Override
86         public void onStop() {
87             Log.i("tag","MainActivity:OnStop");
88             super.onStop();
89         }
90 
91         @Override
92         public void onDestroy() {
93             Log.i("tag","MainActivity:OnDestroy");
94             super.onDestroy();
95         }
96     }
97 }

接着为OtherActivity新建一个布局文件Other.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical" >
 6     <TextView
 7         android:layout_width="match_parent"
 8         android:layout_height="wrap_content"
 9         android:text="Other"
10         />
11 
12 </LinearLayout>

我们让OtherActivity使用Other.xml

 1 public class OtherActivity extends Activity {
 2 
 3     @Override
 4     protected void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6         setContentView(R.layout.other);  // 使用布局文件
 7         Log.i("tag","OtherActivity:OnCreate");
 8     }
 9 
10         ...
11 
12 }

接着我们需要在manifest文件中对其注册

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3     package="first.pack"
 4     android:versionCode="1"
 5     android:versionName="1.0" >
 6 
 7     <uses-sdk
 8         android:minSdkVersion="8"
 9         android:targetSdkVersion="19" />
10 
11     <application
12         android:allowBackup="true"
13         android:icon="@drawable/ic_launcher"
14         android:label="@string/app_name"
15         android:theme="@style/AppTheme" >
16         <activity
17             android:name="first.pack.MainActivity"
18             android:label="@string/FirstMirror" >
19             <intent-filter>
20                 <action android:name="android.intent.action.MAIN" />
21 
22                 <category android:name="android.intent.category.LAUNCHER" />
23             </intent-filter>
24         </activity>
25         <activity
26             android:name="first.pack.OtherActivity"   //添加
27             android:label="@string/SecondMirror" >   //添加
28         </activity>
29     </application>
30 
31 </manifest>

OK，下面我们为第一个Activity添加一个按钮

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:paddingBottom="@dimen/activity_vertical_margin"
 6     android:paddingLeft="@dimen/activity_horizontal_margin"
 7     android:paddingRight="@dimen/activity_horizontal_margin"
 8     android:paddingTop="@dimen/activity_vertical_margin"
 9     tools:context="first.pack.MainActivity$PlaceholderFragment" >
10 
11     <Button
12         android:id="@+id/firstButton"
13         android:layout_width="wrap_content"
14         android:layout_height="wrap_content"
15         android:text="OpenDoor" />
16 
17 </RelativeLayout>

为此按钮在MainActivity中添加监听器

 1 public static class PlaceholderFragment extends Fragment {
 2         
 3         private Button button;
 4 
 5         public PlaceholderFragment() {
 6         }
 7 
 8         @Override
 9         public View onCreateView(LayoutInflater inflater, ViewGroup container,
10                 Bundle savedInstanceState) {
11             View rootView = inflater.inflate(R.layout.fragment_main, container, false);
12             
13             button = (Button)rootView.findViewById(R.id.firstButton);
14             
15             ButtonListener buttonListener = new ButtonListener();
16             button.setOnClickListener(buttonListener);
17             
18             Log.i("tag","MainActivity:OnCreate");
19             return rootView;
20         }
21         
22         class ButtonListener implements android.view.View.OnClickListener{
23 
24             @Override
25             public void onClick(View v) {
26                 Intent intent = new Intent();
27                 intent.setClass(getActivity(),OtherActivity.class);
28                 startActivity(intent);
29             }       
30         }
31         
32         @Override
33         public void onStart() {
34             super.onStart();
35             Log.i("tag","MainActivity:OnStart");
36 
37         }
38 
39         @Override
40         public void onResume() {
41             Log.i("tag","MainActivity:OnResume");
42             super.onResume();
43         }
44 
45         @Override
46         public void onPause() {
47             Log.i("tag","MainActivity:OnPause");
48             super.onPause();
49         }
50 
51         @Override
52         public void onStop() {
53             Log.i("tag","MainActivity:OnStop");
54             super.onStop();
55         }
56 
57         @Override
58         public void onDestroy() {
59             Log.i("tag","MainActivity:OnDestroy");
60             super.onDestroy();
61         }
62     }

接下来就是分析运行结果的过程了，首先启动程序，界面和打印如下所示

点击OpenDoor之后

点击返回键之后

总结： OnCreate 创建新的Activity

OnStart 变得可见时调用

OnResume 可以与用户交互时候调用

OnPause 要启动另外一个Activity时调用

OnStop 变得不可见时调用

OnDestroy 从历史栈中弹出就被销毁

posted @ 2014-07-11 18:03 Mirrorhanman 阅读(284) 评论(0) 收藏举报

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Activity生命周期(二)

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