Drag and Drop

• we can allow your users to move data from one View to another View in the current layout using a graphical drag and drop gesture.
• A drag and drop operation starts when the user makes some gesture that you recognize as a signal to start dragging data.
• In response, your application tells the system that the drag is starting.

The drag/drop process

• Started
• Continuing
• Dropped
• Ended

Started: In response to the user’s gesture to begin a drag, your application calls startDrag() to tell the system to start a drag.

Continuing :The user continues the drag.

Dropped :The user releases the drag shadow within the bounding box of a View that can accept the data.

Ended :After the user releases the drag shadow, and after the system sends out (if necessary) a drag event with action type ACTION_DROP, the system sends out a drag event with action type ACTION_DRAG_ENDED to indicate that the drag operation is over.

The drag shadow

During a drag and drop operation, the system displays a image that the user drags. For data movement, this image represents the data being dragged. For other operations, the image represents some aspect of the drag operation.

layout.xml
<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"
    tools:context="com.compindia.dragdropapp.DropDropActivity">
    <LinearLayout
        android:id="@+id/ll_pinklayout"
        android:orientation="vertical"
        android:layout_height="@dimen/height_lldrop"
        android:background="#FF8989"
        >
        <TextView
            android:id="@+id/tv_dropdrop"
            android:text="Drag Text"
            android:textSize="@dimen/size_tvdrop"
            />
    </LinearLayout>
</RelativeLayout>
activity.java
public class DropDropActivity extends AppCompatActivity implements View.OnTouchListener, View.OnDragListener {
    private String TAG = DropDropActivity.class.getSimpleName();
    private LinearLayout llPinkLayout;
    private TextView tvDragView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_drop_drop);
        setUpViews();
        setListeners();
    }
    private void setListeners() {
        tvDragView.setOnTouchListener(this);
        llPinkLayout.setOnDragListener(this);
    }
    private void setUpViews() {
        llPinkLayout = (LinearLayout) findViewById(R.id.ll_pinklayout);
        tvDragView = (TextView) findViewById(R.id.tv_dropdrop);
    }
    @Override
    public boolean onDrag(View view, DragEvent dragEvent) {
        Log.d(TAG, "onDrag: view->" + view + "\n DragEvent" + dragEvent);
        switch (dragEvent.getAction()) {
            case DragEvent.ACTION_DRAG_ENDED:
                Log.d(TAG, "onDrag: ACTION_DRAG_ENDED ");
                return true;
            case DragEvent.ACTION_DRAG_EXITED:
                Log.d(TAG, "onDrag: ACTION_DRAG_EXITED");
                return true;
            case DragEvent.ACTION_DRAG_ENTERED:
                Log.d(TAG, "onDrag: ACTION_DRAG_ENTERED");
                return true;
            case DragEvent.ACTION_DRAG_STARTED:
                Log.d(TAG, "onDrag: ACTION_DRAG_STARTED");
                return true;
            case DragEvent.ACTION_DROP:
                Log.d(TAG, "onDrag: ACTION_DROP");
                View tvState = (View) dragEvent.getLocalState();
                Log.d(TAG, "onDrag:viewX" + dragEvent.getX() + "viewY" + dragEvent.getY());
                Log.d(TAG, "onDrag: Owner->" + tvState.getParent());
                ViewGroup tvParent =(ViewGroup) tvState.getParent();
                tvParent.removeView(tvState);
                LinearLayout container = (LinearLayout)view;
                container.addView(tvState);
                LinearLayout contariner = (LinearLayout) view;
                tvParent.removeView(tvState);
                tvState.setX(dragEvent.getX());
                tvState.setY(dragEvent.getY());
                ((LinearLayout) view).addView(tvState);
                view.setVisibility(View.VISIBLE);
                return true;
            case DragEvent.ACTION_DRAG_LOCATION:
                Log.d(TAG, "onDrag: ACTION_DRAG_LOCATION");
                return true;
            default:
                return false;
        }
    }
    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        Log.d(TAG, "onTouch: view->view" + view + "\n MotionEvent" + motionEvent);
        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
            View.DragShadowBuilder dragShadowBuilder = new View.DragShadowBuilder(view);
            view.startDrag(null, dragShadowBuilder, view, 0);
            return true;
        } else {
            return false;
        }
    }
}

#output