這個處理程序類應該是靜態的或者可能發生泄漏（com.test.test3.ui.MainActivity.1）

Question

我是新來的android，我嘗試開發一個系統，但是當我完成代碼時，處理程序顯示此警告

顯示我編輯後的代碼，事件ontounch中的處理程序顯示警告處理程序無法解析。我試着把//忽略處理程序，我嘗試運行應用程序及其結果強制關閉。

public class MainActivity extends Activity { 



protected static final int STOP = 100; 
ImageView iv; 
private ProgressBar pb; 
LinearLayout ll; 
private AnimationDrawable anim; 
ScrollView sv; 
private SQLiteDatabase db; 
private boolean flagscanning = false; 


@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    ll = new LinearLayout(this); 
    new HandlerClass(this); 

      db = SQLiteDatabase.openDatabase(Environment.getExternalStorageDirectory()+"/antivirus.sqlite", null, SQLiteDatabase.OPEN_READONLY); 
      iv = (ImageView) this.findViewById(R.id.imageView1); 
        //掃描病毒進度條 
      pb = (ProgressBar) this.findViewById(R.id.progressBar1); 
      ll = (LinearLayout) this.findViewById(R.id.ll); 
        //設置ImageView背景資源爲動畫文件 
      iv.setBackgroundResource(R.drawable.bg); 
        //sv用來顯示病毒的掃描結果 
      sv = (ScrollView) this.findViewById(R.id.scrollView1); 
      anim = (AnimationDrawable) iv.getBackground(); 
} 

private static class HandlerClass extends Handler{ 
    private final WeakReference<MainActivity> mTarget; 
    public HandlerClass(MainActivity context){ 
     mTarget = new WeakReference<MainActivity>((MainActivity) context); 
    } 

    @Override 
    public void handleMessage(Message msg) { 
     super.handleMessage(msg); 
     MainActivity target = mTarget.get(); 
     if(msg.what==STOP){ 
      target.ll.removeAllViews(); 
      //anim.stop(); 

      } 
     String str = (String) msg.obj; 
     TextView tv = new TextView(target); 
     tv.setText(str); 
     target.ll.setOrientation(LinearLayout.VERTICAL); 
     target.ll.addView(tv); 
     //sv.scrollBy(0, 20); 

     System.out.println(str); 

    } 
}; 


@Override 
public boolean onTouchEvent(MotionEvent event) { 
    //如果程序正在殺毒過程中，拒絕再次啓動殺毒線程 
    if(flagscanning){ 
     return false; 
    } 

    //如果用戶觸摸屏幕，則開啓殺毒線程 
    if (event.getAction() == MotionEvent.ACTION_UP) { 
     flagscanning= true; 
     anim.start(); 
     new Thread() { 
      public void run() { 
       // 獲取每一個應用程序的簽名，簽名須與數據庫的簽名想比較 
       List<PackageInfo> infos = getPackageManager() 
         .getInstalledPackages(PackageManager.GET_UNINSTALLED_PACKAGES | PackageManager.GET_SIGNATURES); 
       //設置進度條的掃描範圍 
       pb.setMax(infos.size()); 
       int total = 0; 
       int virustotal = 0;//設置初始病毒數爲0 
       for (PackageInfo info : infos) { 
        total++; 
        try { 
         sleep(20);//只爲便於觀察掃描效果和進度，無實質作用 
        } catch (InterruptedException e) { 
         e.printStackTrace(); 
        } 
        Message msg = Message.obtain(); 
        msg.obj = "正在掃描" + info.packageName; 
        _handler.sendMessage(msg);_ 
        Signature[] signs = info.signatures; 
        String str = signs[0].toCharsString(); 

        String md5 = MD5Encoder.encode(str); 
        //將應用程序簽名與數據庫中保存的簽名進行比較，如果相一致，則使病毒數加1，並通過handler在界面顯示病毒包名 
        Cursor cursor = db.rawQuery("select desc from datable where md5=?",new String[] { md5 }); 
        if (cursor.moveToFirst()) { 
         String desc = cursor.getString(0); 
         msg = Message.obtain(); 
         msg.obj = info.packageName + ": " + desc; 
         _handler.sendMessage(msg);_ 
         virustotal++; 
        } 
        cursor.close(); 
        pb.setProgress(total); 

       } 
       Message msg = Message.obtain(); 
       msg.what = STOP; 
       msg.obj = "掃描完畢 ,共發現" + virustotal + "個病毒"; 
       _handler.sendMessage(msg);_ 
       flagscanning = false; 
       pb.setProgress(0); 
      }; 
     }.start(); 
    } 
    return super.onTouchEvent(event); 
} 

@Override 
protected void onDestroy() { 
    if (db.isOpen()) 
     db.close(); 
    super.onDestroy(); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.main, menu); 
    return true; 
} 
} 

Answer 1

讓你處理一個靜態類。

該警告是一個皮棉警告。您可以禁用警告，但它是一個有用的信息

這裏的皮棉列表檢查

http://tools.android.com/tips/lint-checks

從源報價@

http://android-developers.blogspot.in/2009/01/avoiding-memory-leaks.html

避免在非靜態內部類一個活動，如果你不控制他們的生命週期，使用一個靜態的內部類，並對內部的活動做一個弱引用。

此問題的解決方案是對外部類使用一個帶有WeakReference的靜態內部類，如ViewRoot及其W內部類所示。

另請查看關於android開發人員組的討論。通過羅曼蓋伊檢查解決方案從羅曼蓋伊的解決方案

https://groups.google.com/forum/#!topic/android-developers/1aPZXZG6kWk

例如，從上面的鏈接

class OuterClass { 
class InnerClass { 
    private final WeakReference<OuterClass> mTarget; 

    InnerClass(OuterClass target) { 
    mTarget = new WeakReference<OuterClass>(target); 
    } 

    void doSomething() { 
    OuterClass target = mTarget.get(); 
    if (target != null) target.do(); 
    } 

編輯：

例子：

public class MainActivity extends Activity { 

     LinearLayout ll; 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     ll = new LinearLayout(this); 
     new HandlerClass(this); 
    } 
     private static class HandlerClass extends Handler{ 
      private final WeakReference<MainActivity> mTarget; 
     public HandlerClass(MainActivity context) 
     { 
      mTarget = new WeakReference<MainActivity>((MainActivity) context); 

     } 

      @Override 
      public void handleMessage(Message msg) { 
       super.handleMessage(msg); 
       MainActivity target = mTarget.get(); 
       if (target != null) 
       if(msg.what==1){ 
        target.ll.removeAllViews(); 
        // anim.stop(); 

        } 
       String str = (String) msg.obj; 
       TextView tv = new TextView(target); 
       tv.setText(str); 
       target.ll.setOrientation(LinearLayout.VERTICAL); 
       target.ll.addView(tv); 
       //sv.scrollBy(0, 20); 

       System.out.println(str); 

      } 

     }; 
} 

如果糾正我，以上是錯誤的或有一些問題。

您還可以查看該博客由亞歷克斯·洛克伍德

http://www.androiddesignpatterns.com/2013/01/inner-class-handler-memory-leak.html

Answer 2

當你定義一個匿名內部類這樣，類本身被重新定義爲MainActivity每個實例。顯然，Android SDK標記爲有可能泄漏這些類定義。最簡單的辦法是讓一個靜態內部類，需要一個參考MainActivity在構造函數中：

public class MainActivity extends Activity { 
    //Fields and methods of MainActivity... 
    private static final class MainHandler extends Handler { 
     private final MainActivity caller; 
     private MainHandler(final MainActivity caller) { this.caller = caller; } 
     @Override public void handleMessage(Message msg) { //Your existing logic } 
    } 
}