Android 优化Handler防止内存泄露

Android 优化Handler防止内存泄露

Demo描述: 

 Handler可能导致的内存泄露及其优化    

  1 关于常见的Handler的用法但是可能导致内存泄露 

  2 优化方式请参考BetterHandler和BetterRunnable的实现

package cc.cc; 
 
import java.lang.ref.WeakReference; 
import android.os.Bundle; 
import android.os.Handler; 
import android.os.Message; 
import android.app.Activity; 
 
public class MainActivity extends Activity { 
  private Handler mHandler; 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
  } 
   
   
   
  private void initHandler() { 
    mHandler = new Handler() { 
      @Override 
      public void handleMessage(Message msg) { 
 super.handleMessage(msg); 
      } 
    }; 
 
    // ......doing something 
    // ......doing something 
    // ......doing something 
 
    // 发送延迟消息 
    mHandler.postDelayed(new Runnable() { 
      @Override 
      public void run() { 
 
      } 
    }, 1000 * 20); 
  } 
   
   
   
   
  private static class BetterHandler extends Handler{ 
    private final WeakReference activityWeakReference; 
    public BetterHandler(Activity activity){ 
      activityWeakReference=new WeakReference(activity); 
    } 
    @Override 
    public void handleMessage(Message msg) { 
      super.handleMessage(msg); 
      if (activityWeakReference.get()!=null) { 
 //.....handle message 
      } else { 
 System.out.println("Activity==null"); 
      } 
    } 
  } 
   
  //同样采用静态内部类 
  private static class BetterRunnable implements Runnable{ 
    @Override 
    public void run() { 
      // ......doing something 
    } 
     
  } 
   
  //发送延迟消息 
  private void sendMessage(){ 
    BetterHandler betterHandler=new BetterHandler(MainActivity.this); 
    betterHandler.postDelayed(new BetterRunnable(), 1000 * 20); 
  } 
   
 
} 

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