5.User Interface/Drag and Drop

package mirror.android.dragdrop;

import android.app.Activity;
import android.content.ClipDescription;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnClickListener;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.widget.Button;
import android.widget.Toast;


public class DragActivity extends Activity {

    private Button button;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_drag);
        
        button = (Button)findViewById(R.id.dragButton);
        
        myDragEventListener mDragListenr = new myDragEventListener();
        button.setOnDragListener(mDragListenr);
        
        button.setOnLongClickListener(new OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                button.startDrag(null, new DragShadowBuilder(v), (Object)v, 0);
                return true;
            }
        });
    }
    
    class myDragEventListener implements OnDragListener{
        @Override
        public boolean onDrag(View v, DragEvent event) {
            
            // Defines a variable to store the action type for the incoming event
            final int action = event.getAction();
            
            switch (action) {
                case DragEvent.ACTION_DRAG_STARTED:
                    // Returns false. During the current drag and drop operation, this View will
                    // not receive events again until ACTION_DRAG_ENDED is sent.
                    return false;
                case DragEvent.ACTION_DRAG_ENTERED:
                    //when the drag shadow has just entered the bounding box of the View
                    return true;
                case DragEvent.ACTION_DRAG_LOCATION:
                    //receives this event action type after it receives ACTION_DRAG_ENTERED
                    return true;
                case DragEvent.ACTION_DRAG_EXITED:
                    //receives a ACTION_DRAG_ENTERED and at least one ACTION_DRAG_LOCATION
                    return true;
                case DragEvent.ACTION_DROP:
                    //when the user releases the drag shadow over the View object
                    return true;
                case DragEvent.ACTION_DRAG_ENDED:
                    //when the system is ending the drag operation
                    return true;
                default:
                    break;
            }
            return false;
        }
    }
}

Example2:

http://blog.csdn.net/mayingcai1987/article/details/6221988

package mirror.android.draganddropactivity;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;

public class AreaOne extends View {

    public AreaOne(Context context) {
        super(context);
    }
    
    public AreaOne(Context context, AttributeSet attrs){
        super(context,attrs);
    }

}

package mirror.android.draganddropactivity;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.DragEvent;
import android.view.View;

public class AreaTwo extends View {
    
    public AreaTwo(Context context) { 
        super(context); 
    }  
  
    public AreaTwo(Context context, AttributeSet attrs) { 
        super(context, attrs); 
    }

    @Override
    public boolean onDragEvent(DragEvent event) {
        boolean result = false; 
        
        switch (event.getAction()) { 
            case DragEvent.ACTION_DRAG_STARTED: { 
                Log.i("mayingcai", "有View开始被拖动!"); 
                //在拖动开始时，只有返回true，后面的动作（ACTION_DRAG_ENTERED, ACTION_DRAG_LOCATION, ACTION_DROP）才会被执行! 
                result = true; 
                break; 
            }  
            case DragEvent.ACTION_DRAG_ENTERED: { 
                Log.i("mayingcai", "被拖动的View进入当前View!"); 
                break; 
            }  
            case DragEvent.ACTION_DRAG_LOCATION: { 
                Log.i("mayingcai", "被拖动的View进入当前View后，位置发生改变!"); 
                break; 
            }  
            case DragEvent.ACTION_DROP: { 
                Log.i("mayingcai", "拖动的View被放入当前View!"); 
                //在放时交互两个View的背景。 
                View mDragView = (View) event.getLocalState(); 
                Drawable mDragViewBackgroud = mDragView.getBackground(); 
                mDragView.setBackgroundDrawable(this.getBackground()); 
                this.setBackgroundDrawable(mDragViewBackgroud); 
                break; 
            }  
  
            case DragEvent.ACTION_DRAG_ENDED: { 
                Log.i("mayingcai", "拖动结束!"); 
                break; 
            }  
      
            case DragEvent.ACTION_DRAG_EXITED: { 
                Log.i("mayingcai", "拖动退出!"); 
                break; 
            }  
      
            default: 
                break; 
        }  
        return result;  
    }  
}

<LinearLayout 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:orientation="vertical"
    tools:context="mirror.android.draganddropactivity.DragAndDropActivity" >

    <mirror.android.draganddropactivity.AreaOne
        android:id = "@+id/areaOne"  
        android:layout_width = "100dip"  
        android:layout_height = "100dip"  
        android:background = "#FF0000"/>
    
    <TextView
        android:layout_width = "100dip"  
        android:layout_height = "100dip"/>
    
    <mirror.android.draganddropactivity.AreaTwo 
        android:id = "@+id/areaTwo"  
        android:layout_width = "100dip"  
        android:layout_height = "100dip"  
        android:background = "#00FF00" />

</LinearLayout>

package mirror.android.draganddropactivity;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnLongClickListener;


public class DragAndDropActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_drag_and_drop);
        
        final View mAreaOne = findViewById(R.id.areaOne);
        mAreaOne.setOnLongClickListener(new OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                //长按AreaOne开始启动
                mAreaOne.startDrag(null, new DragShadowBuilder(v), (Object)v, 0);                
                return true;
            }
        });
    }
}