拖放圖像可見性

Question

我想拖動一個圖像並將其放在另一個圖像上。到目前爲止，我得到了影子的工作，當用戶拖動圖像時，它會做一些事情。我想要做的是使圖像在拖動時顯示，因爲只顯示陰影。

嘗試使用此how to drag and drop a image onto a image，但無法理解它。我認爲我的剪輯數據有誤。

<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.example.imagedrop.MainActivity" > 

    <ImageView 
     android:id="@+id/view" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:src="@drawable/ic_launcher" 
     android:contentDescription="@string/v"/> 

    <ImageView 
     android:id="@+id/target" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_below="@+id/view" 
     android:layout_centerHorizontal="true" 
     android:layout_marginTop="118dp" 
     android:src="@drawable/ic_launcher" 
     android:contentDescription="@string/v" /> 

</RelativeLayout> 

的Java

public class MainActivity extends Activity {  

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

    //get image 
     findViewById(R.id.view).setOnLongClickListener(longListen); 
     findViewById(R.id.target).setOnDragListener(dropListener); 
    } 


    @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; 
    } 

    OnLongClickListener longListen = new OnLongClickListener() { 

     @Override 

     public boolean onLongClick(View v) { 


      //dragshadow created 
      DragShadow dragShadow = new DragShadow(v); 

      // clip data 
      ClipData data = ClipData.newPlainText("", ""); 


      v.startDrag(data, dragShadow, v, 0); 
      return false; 
     } 
    }; 


    OnDragListener dropListener = new OnDragListener() { 

     public boolean onDrag(View v, DragEvent event) 
     { 
      int dragEvent = event.getAction();        

      switch (dragEvent) { 
      case DragEvent.ACTION_DRAG_STARTED: 
       Log.i("Drag Event", "Started"); 
       break; 

      case DragEvent.ACTION_DRAG_ENTERED: 

       Log.i("Drag Event", "Entered"); 
       break; 

      case DragEvent.ACTION_DRAG_EXITED: 
       Log.i("Drag Event", "Exited"); 
       break; 

      case DragEvent.ACTION_DROP:    
       //sends to new activity    
       break; 
      } 
      return true; 
     } 

    };  



    private class DragShadow extends View.DragShadowBuilder { 
     //greybox drawable made 
     ColorDrawable greyBox; 


     public DragShadow(View view) { 
      super(view); 
      greyBox = new ColorDrawable(Color.LTGRAY); 
     } 

     @Override 
     public void onDrawShadow(Canvas canvas) { 

      greyBox.draw(canvas); 
     } 

     @Override 
     public void onProvideShadowMetrics(Point shadowSize, 
       Point shadowTouchPoint) { 

      View v = getView(); 

      int height = (int) v.getHeight()/2; 
      int width = (int) v.getWidth()/2; 


      greyBox.setBounds(0, 0, width, height); 

      shadowSize.set(width, height); 

      shadowTouchPoint.set((int) width/2, (int) height/2); 

     } 

    }  


    } 

Answer 1

我已經實現了與此庫DraggablePanel此相同的行爲。

祝你好運。