Android 中 ActivityLifecycleCallbacks的实例详解

程序员文章站 2023-12-18 22:34:52

android 中 activitylifecyclecallbacks的实例详解 &...

android 中 activitylifecyclecallbacks的实例详解

以上就是使用activitylifecyclecallbacks的实例，代码注释写的很清楚大家可以参考下，

myapplication如下:

package com.cc; 
 
import java.util.linkedlist; 
 
import android.app.activity; 
import android.app.application; 
import android.os.bundle; 
/** 
 * demo示例: 
 * activitylifecyclecallbacks使用示例 
 * 
 * activitylifecyclecallbacks用于对应用中activity的生命周期的追踪和回调 
 * 
 * 使用activitylifecyclecallbacks可实现: 
 * 1 判断app是否在后台运行 
 * 2 关闭该应用所有activity 
 * 
 * 
 * (1)判断app是否在后台运行 
 * 在该实现中采用activitycounter记录activity的个数. 
 * 通过对于activitycounter是否为0判断当前app是否在前台运行. 
 * 
 * 从activitylifecyclecallbacks的实现方法中我们的惯性思维是: 
 * 在activitylifecyclecallbacks的onactivityresumed()中activitycounter+1. 
 * 在onactivitypaused()中activitycounter-1, 
 * 但是这么对么？ 
 * 
 * 先看一下界面跳转时两个activity的生命周期 
 * 当从activity a跳转到activity b时,两个activity的生命周期如下: 
 * a.onpause()->b.oncreate()->b.onstart()-> b.onresume()-> a.onstop() 
 * 
 * 假若按照上述方式那么: 
 * 在a启动后activitycounter=1; 
 * 当从a跳转到b时在调用a.onpause()时执行:activitycounter-1=0; 
 * 即该app运行在后台. 
 * 这当然是错的,两个界面切换的过程中app当然是运行在前台的。 
 * 
 * 如下修改: 
 * 在onactivitystarted()中对于activitycounter+1 
 * 在onactivitystopped()中对于activitycounter-1 
 * 小结:注意activity跳转时的生命周期 
 * 
 * (2)关闭该应用所有activity 
 *  2.1 利用linkedlist<activity>管理应用中的界面 
 *  2.2 在activitylifecyclecallbacks的onactivitycreated() 
 *    将activity添加到linkedlist中 
 *    在activitylifecyclecallbacks的onactivitydestroyed() 
 *    将activity从linkedlist中移除 
 *  2.3 关闭应用时销毁linkedlist中所有activity 
 * 
 * 备注说明: 
 * 1 activitylifecyclecallbacks是在api 14及其以上才有的 
 * 2 在android4.0以下可以在baseactivity中按照该思路实现 
 * 
 */ 
public class myapplication extends application { 
  private static int activitycounter=0; 
  private static myapplication mapplicationinstance; 
  private static linkedlist<activity> mactivitylinkedlist; 
  private activitylifecyclecallbacksimpl mactivitylifecyclecallbacksimpl; 
  @override 
  public void oncreate() { 
    super.oncreate(); 
    mapplicationinstance=new myapplication(); 
    mactivitylinkedlist=new linkedlist<activity>(); 
    mactivitylifecyclecallbacksimpl=new activitylifecyclecallbacksimpl(); 
    this.registeractivitylifecyclecallbacks(mactivitylifecyclecallbacksimpl); 
  } 
   
  public static myapplication getinstance() { 
    if (null==mapplicationinstance) { 
      mapplicationinstance=new myapplication(); 
    } 
    return mapplicationinstance; 
  } 
   
  //判断app是否在后台运行 
  public boolean isapprunningbackground(){ 
    boolean flag=false; 
    if(activitycounter==0){ 
      flag=true; 
    } 
    return flag; 
  } 
   
  //退出应用 
  public void finishallactivity(){ 
    //unregisteractivitylifecyclecallbacks(mactivitylifecyclecallbacksimpl); 
    system.out.println("--> mactivitylinkedlist.size()="+mactivitylinkedlist.size()); 
    if(null!=mactivitylinkedlist){ 
      for(activity activity:mactivitylinkedlist){ 
        if(null!=activity){ 
          activity.finish(); 
        } 
      } 
    } 
  } 
   
   
  private class activitylifecyclecallbacksimpl implements activitylifecyclecallbacks{ 
    @override 
    public void onactivitycreated(activity activity, bundle savedinstancestate) { 
      system.out.println("onactivitycreated --> "+activity.getclass().getname()); 
      if (null!=mactivitylinkedlist&&null!=activity) { 
        mactivitylinkedlist.addfirst(activity); 
      } 
    } 
 
    @override 
    public void onactivitystarted(activity activity) { 
      activitycounter++; 
      system.out.println("onactivitystarted --> "+activity.getclass().getname()+",activitycounter="+activitycounter); 
    } 
 
    @override 
    public void onactivityresumed(activity activity) { 
      system.out.println("onactivityresumed --> "+activity.getclass().getname()); 
    } 
 
    @override 
    public void onactivitypaused(activity activity) { 
      system.out.println("onactivitypaused --> "+activity.getclass().getname()); 
    } 
 
    @override 
    public void onactivitystopped(activity activity) { 
      activitycounter--; 
      system.out.println("onactivitystopped --> "+activity.getclass().getname()+",activitycounter="+activitycounter); 
    } 
 
    @override 
    public void onactivitysaveinstancestate(activity activity, bundle outstate) { 
      system.out.println("onactivitysaveinstancestate --> "+activity.getclass().getname()); 
    } 
 
    @override 
    public void onactivitydestroyed(activity activity) { 
      system.out.println("onactivitydestroyed --> "+activity.getclass().getname()); 
      if (null!=mactivitylinkedlist&&null!=activity) { 
        if (mactivitylinkedlist.contains(activity)) { 
          mactivitylinkedlist.remove(activity); 
        } 
      } 
    } 
     
  } 
 
}

firstactivity如下:

package com.cc; 
 
import android.app.activity; 
import android.content.context; 
import android.content.intent; 
import android.os.bundle; 
import android.view.view; 
import android.view.view.onclicklistener; 
import android.widget.button; 
public class firstactivity extends activity { 
   private context mcontext; 
   private button mopennewactivitybutton; 
   private button mfinishthisactivitybutton; 
   private clicklistenerimpl mclicklistenerimpl; 
  @override 
  protected void oncreate(bundle savedinstancestate) { 
    super.oncreate(savedinstancestate); 
    setcontentview(r.layout.first_activity); 
    init(); 
  } 
   
  private void init(){ 
    mcontext=this; 
    mclicklistenerimpl=new clicklistenerimpl(); 
    mopennewactivitybutton=(button) findviewbyid(r.id.opennewactivitybutton); 
    mopennewactivitybutton.setonclicklistener(mclicklistenerimpl); 
    mfinishthisactivitybutton=(button) findviewbyid(r.id.finishthisactivitybutton); 
    mfinishthisactivitybutton.setonclicklistener(mclicklistenerimpl); 
  } 
   
   
  private class clicklistenerimpl implements onclicklistener { 
    @override 
    public void onclick(view v) { 
      switch (v.getid()) { 
      case r.id.opennewactivitybutton: 
        intent intent=new intent(mcontext, secondactivity.class); 
        startactivity(intent); 
        break; 
      case r.id.finishthisactivitybutton: 
        finish(); 
        break; 
 
      default: 
        break; 
      } 
 
    } 
 
  } 
   
  @override 
  protected void onresume() { 
    super.onresume(); 
    //system.out.println(" first activity onresume --> "+myapplication.getinstance().isapprunningbackground()); 
  } 
   
  @override 
  protected void onstop() { 
    super.onstop(); 
    //system.out.println(" first activity onstop --> "+myapplication.getinstance().isapprunningbackground()); 
  } 
   
   
}

secondactivity如下:

package com.cc; 
 
import android.app.activity; 
import android.content.context; 
import android.content.intent; 
import android.os.bundle; 
import android.view.view; 
import android.view.view.onclicklistener; 
import android.widget.button; 
 
public class secondactivity extends activity { 
   private context mcontext; 
   private button mopennewactivitybutton; 
   private button mfinishthisactivitybutton; 
   private clicklistenerimpl mclicklistenerimpl; 
  @override 
  protected void oncreate(bundle savedinstancestate) { 
    super.oncreate(savedinstancestate); 
    setcontentview(r.layout.second_activity); 
    init(); 
  } 
   
  private void init(){ 
    mcontext=this; 
    mclicklistenerimpl=new clicklistenerimpl(); 
    mopennewactivitybutton=(button) findviewbyid(r.id.opennewactivitybutton); 
    mopennewactivitybutton.setonclicklistener(mclicklistenerimpl); 
    mfinishthisactivitybutton=(button) findviewbyid(r.id.finishthisactivitybutton); 
    mfinishthisactivitybutton.setonclicklistener(mclicklistenerimpl); 
  } 
   
   
  private class clicklistenerimpl implements onclicklistener { 
    @override 
    public void onclick(view v) { 
      switch (v.getid()) { 
      case r.id.opennewactivitybutton: 
        intent intent=new intent(mcontext, thirdactivity.class); 
        startactivity(intent); 
        break; 
 
      case r.id.finishthisactivitybutton: 
        finish(); 
        break; 
 
      default: 
        break; 
      } 
 
    } 
 
  } 
 
   
}

thirdactivity如下:

package com.cc; 
 
import android.app.activity; 
import android.content.context; 
import android.content.intent; 
import android.os.bundle; 
import android.view.view; 
import android.view.view.onclicklistener; 
import android.widget.button; 
 
public class thirdactivity extends activity { 
   private context mcontext; 
   private button mfinishallactivitybutton; 
   private button mfinishthisactivitybutton; 
   private clicklistenerimpl mclicklistenerimpl; 
  @override 
  protected void oncreate(bundle savedinstancestate) { 
    super.oncreate(savedinstancestate); 
    setcontentview(r.layout.third_activity); 
    init(); 
  } 
   
  private void init(){ 
    mcontext=this; 
    mclicklistenerimpl=new clicklistenerimpl(); 
    mfinishthisactivitybutton=(button) findviewbyid(r.id.finishthisactivitybutton); 
    mfinishthisactivitybutton.setonclicklistener(mclicklistenerimpl); 
    mfinishallactivitybutton=(button) findviewbyid(r.id.finishallactivitybutton); 
    mfinishallactivitybutton.setonclicklistener(mclicklistenerimpl); 
  } 
   
   
  private class clicklistenerimpl implements onclicklistener { 
    @override 
    public void onclick(view v) { 
      switch (v.getid()) { 
      case r.id.finishthisactivitybutton: 
        finish(); 
        break; 
      case r.id.finishallactivitybutton: 
        myapplication.getinstance().finishallactivity(); 
        break; 
      default: 
        break; 
      } 
 
    } 
  } 
   
  @override 
  protected void onresume() { 
    super.onresume(); 
    //system.out.println(" third activity onresume --> "+myapplication.getinstance().isapprunningbackground()); 
  } 
   
  @override 
  protected void onstop() { 
    super.onstop(); 
    //system.out.println(" third activity onstop --> "+myapplication.getinstance().isapprunningbackground()); 
  } 
   
  @override 
  protected void ondestroy() { 
    super.ondestroy(); 
    //system.out.println(" third activity ondestroy --> "+myapplication.getinstance().isapprunningbackground()); 
  } 
 
   
}

first_activity.xml如下:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:paddingbottom="@dimen/activity_vertical_margin" 
  android:paddingleft="@dimen/activity_horizontal_margin" 
  android:paddingright="@dimen/activity_horizontal_margin" 
  android:paddingtop="@dimen/activity_vertical_margin" 
  tools:context="com.cc.firstactivity" > 
 
  <button 
    android:id="@+id/opennewactivitybutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_centerinparent="true" 
    android:text="open new activity" /> 
 
  <textview 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_above="@id/opennewactivitybutton" 
    android:layout_centerinparent="true" 
    android:layout_marginbottom="50dip" 
    android:textsize="20sp" 
    android:textcolor="@android:color/holo_red_light" 
    android:text="this is the first activity" /> 
 
  <button 
    android:id="@+id/finishthisactivitybutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_below="@id/opennewactivitybutton" 
    android:layout_centerhorizontal="true" 
    android:layout_margintop="50dip" 
    android:text="finish this activity" /> 
 
</relativelayout>

second_activity.xml如下:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:paddingbottom="@dimen/activity_vertical_margin" 
  android:paddingleft="@dimen/activity_horizontal_margin" 
  android:paddingright="@dimen/activity_horizontal_margin" 
  android:paddingtop="@dimen/activity_vertical_margin" 
  tools:context="com.cc.firstactivity" > 
 
  <button 
    android:id="@+id/opennewactivitybutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_centerinparent="true" 
    android:text="open new activity" /> 
 
  <textview 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_above="@id/opennewactivitybutton" 
    android:layout_centerinparent="true" 
    android:layout_marginbottom="50dip" 
    android:textsize="20sp" 
    android:textcolor="@android:color/holo_red_light" 
    android:text="this is the second activity" /> 
 
  <button 
    android:id="@+id/finishthisactivitybutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_below="@id/opennewactivitybutton" 
    android:layout_centerhorizontal="true" 
    android:layout_margintop="50dip" 
    android:text="finish this activity" /> 
 
</relativelayout>

third_activity.xml如下:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:paddingbottom="@dimen/activity_vertical_margin" 
  android:paddingleft="@dimen/activity_horizontal_margin" 
  android:paddingright="@dimen/activity_horizontal_margin" 
  android:paddingtop="@dimen/activity_vertical_margin" 
  tools:context="com.cc.firstactivity" > 
 
  <textview 
    android:id="@+id/textview" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_above="@id/opennewactivitybutton" 
    android:layout_centerhorizontal="true" 
    android:layout_margintop="100dp" 
    android:text="this is the third activity" 
    android:textcolor="@android:color/holo_red_light" 
    android:textsize="20sp" /> 
 
  <button 
    android:id="@+id/finishthisactivitybutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_below="@id/textview" 
    android:layout_centerhorizontal="true" 
    android:layout_margintop="50dip" 
    android:text="finish this activity" /> 
 
  <button 
    android:id="@+id/finishallactivitybutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_below="@id/finishthisactivitybutton" 
    android:layout_centerhorizontal="true" 
    android:layout_margintop="50dip" 
    android:text="finish all activity" /> 
 
</relativelayout>

androidmanifest.xml如下:

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
  package="com.cc" 
  android:versioncode="1" 
  android:versionname="1.0" > 
 
  <uses-sdk 
    android:minsdkversion="14" 
    android:targetsdkversion="14" /> 
 
  <application 
    android:name="com.cc.myapplication" 
    android:allowbackup="true" 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    android:theme="@style/apptheme" > 
    <activity 
      android:name=".firstactivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
        <action android:name="android.intent.action.main" /> 
 
        <category android:name="android.intent.category.launcher" /> 
      </intent-filter> 
    </activity> 
     
    <activity android:name="com.cc.secondactivity"/> 
    <activity android:name="com.cc.thirdactivity"/> 
  </application> 
 
</manifest>

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