How can i drag and drop multiple imageviews over other imageviews android

Question

I am new to Android. The present code can drag and drop multiple Image Views on a single ImageView but I am not able to drop them on multiple Image Views. Kindly help as in how can I modify my code or any other existing code.

MainActivity.java

package n.f.letters;

import android.app.Activity;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class MainActivity extends Activity implements OnTouchListener {
    /** Called when the activity is first created. */
    private View selected_item = null;
    private int offset_x = 0;
    private int offset_y = 0;
    Boolean touchFlag=false;
    boolean dropFlag=false;
    LayoutParams imageParams;
    ImageView imageDrop,image1,image2,image3,image4;
    int crashX,crashY;
    Drawable dropDrawable,selectDrawable;
    Rect dropRect,selectRect;
    int topy,leftX,rightX,bottomY;

    int dropArray[]; 

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);
        ViewGroup container = (ViewGroup) findViewById(R.id.container);
        imageDrop=(ImageView) findViewById(R.id.ImgDrop);       
        image1=(ImageView) findViewById(R.id.img1);
        image2=(ImageView) findViewById(R.id.img2);
        image3=(ImageView) findViewById(R.id.img3);
        image4=(ImageView) findViewById(R.id.img4);
        container.setOnTouchListener(new View.OnTouchListener() 
        {
            public boolean onTouch(View v, MotionEvent event) 
            {
                if(touchFlag==true)
                {
                  switch (event.getActionMasked()) 
                    {
                    case MotionEvent.ACTION_DOWN :

                         topy=imageDrop.getTop();
                         leftX=imageDrop.getLeft();
                         rightX=imageDrop.getRight();   
                         bottomY=imageDrop.getBottom();

                        //opRect.
                        break;
                    case MotionEvent.ACTION_MOVE:
                        crashX=(int) event.getX();
                        crashY=(int) event.getY();


                        int x = (int) event.getX() - offset_x;
                        int y = (int) event.getY()- offset_y;                                          

                        int w = getWindowManager().getDefaultDisplay().getWidth() - 50;
                        int h = getWindowManager().getDefaultDisplay().getHeight() - 10;
                        if (x > w)
                            x = w;
                        if (y > h)
                            y = h;                      
                        RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(new ViewGroup.MarginLayoutParams(  RelativeLayout.LayoutParams.WRAP_CONTENT,   RelativeLayout.LayoutParams.WRAP_CONTENT));
                        lp.setMargins(x, y, 0, 0);                  

                        //Drop Image Here                       
                        if(crashX > leftX && crashX < rightX && crashY > topy && crashY < bottomY )                     
                        {                           
                            Drawable temp=selected_item.getBackground();                            
                            imageDrop.setBackgroundDrawable(temp);
                            imageDrop.bringToFront();                           
                            dropFlag=true;
                            selected_item.setVisibility(View.INVISIBLE);
                        }
                        //Drop Image Here                       
                        selected_item.setLayoutParams(lp);
                        break;  
                    case MotionEvent.ACTION_UP:
                        //                      
                        touchFlag=false;
                        if(dropFlag==true)
                        {
                            dropFlag=false;
                        }
                        else
                        {
                            selected_item.setLayoutParams(imageParams);
                        }                       
                        break;
                    default:
                        break;
                    }
                }else
                {
                    System.err.println("Display Else Part ::->"+touchFlag);
                }               
                return true;
            }
        });

        image1.setOnTouchListener(this);
        image2.setOnTouchListener(this);
        image3.setOnTouchListener(this);
        image4.setOnTouchListener(this);
    }

    public boolean onTouch(View v, MotionEvent event) 
    {   
        switch (event.getActionMasked()) 
        {
        case MotionEvent.ACTION_DOWN:
            touchFlag=true;
            offset_x = (int) event.getX();
            offset_y = (int) event.getY();
            selected_item = v;
            imageParams=v.getLayoutParams();
            break;
        case MotionEvent.ACTION_UP:
            selected_item=null;
            touchFlag=false;
            break;
        default:
            break;
        }       
        return false;
    }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/container"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<ImageView
    android:id="@+id/ImgDrop"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:background="#FFF123" />

<ImageView
    android:id="@+id/img4"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:layout_marginRight="75dp"
    android:layout_marginTop="61dp"
    android:background="@drawable/ic_launcher" />

<ImageView
    android:id="@+id/img3"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:layout_alignTop="@+id/img4"
    android:layout_toRightOf="@+id/ImgDrop"
    android:background="@drawable/ic_launcher" />

<ImageView
    android:id="@+id/img2"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:layout_alignRight="@+id/ImgDrop"
    android:layout_alignTop="@+id/img3"
    android:layout_marginRight="23dp"
    android:background="@drawable/ic_launcher" />

<ImageView
    android:id="@+id/img1"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:layout_alignTop="@+id/img2"
    android:layout_marginRight="40dp"
    android:layout_toLeftOf="@+id/img2"
    android:background="@drawable/ic_launcher" />

Answer 1

Drag and Drop With the Android drag/drop framework, you can allow your users to move data from one View to another View in the current layout using a graphical drag and drop gesture. The framework includes a drag event class, drag listeners, and helper methods and classes.

Although the framework is primarily designed for data movement, you can use it for other UI actions. For example, you could create an app that mixes colors when the user drags a color icon over another icon. The rest of this topic, however, describes the framework in terms of data movement. link see