Android Open Source - PlayTunes Drag N Drop List View

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License

The source code is released under:
Copyright (c) 2014, Impeccable Labs, LLC. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions ar...
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Java Source Code

/*
 * Copyright (C) 2010 Eric Harlow//w  w  w . j  a va 2 s.c  om
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.ideabag.playtunes.DragNDrop;

import com.ideabag.playtunes.R;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.PixelFormat;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.AbsListView;
import android.widget.ImageView;
import android.widget.ListView;

public class DragNDropListView extends ListView {
  
  // Used to toggle whether the list items can be dragged or not
  
  boolean mDraggingEnabled = false;
  
  boolean mDragMode;

  int mStartPosition;
  int mEndPosition;
  int mDragPointOffset;    //Used to adjust drag view location
  
  int mDragHandleWidth;
  
  ImageView mDragView;
  //View mDragShadow;
  
  //GestureDetector mGestureDetector;
  
  DropListener mDropListener;
  RemoveListener mRemoveListener;
  DragListener mDragListener;
  
  public DragNDropListView(Context context, AttributeSet attrs) {
    super(context, attrs);
    
    Resources r = context.getResources();
    
    mDragHandleWidth = r.getDimensionPixelSize( R.dimen.drag_handle_width );
    
    
    //setOnScrollListener( mScrollListener );
    
  }
  
  public void setDropListener(DropListener l) {
    mDropListener = l;
  }

  public void setRemoveListener(RemoveListener l) {
    mRemoveListener = l;
  }
  
  public void setDragListener(DragListener l) {
    mDragListener = l;
  }
  
  public void setDraggingEnabled( boolean enabled ) {
    
    mDraggingEnabled = enabled;
    
  }

  @Override
  public boolean onTouchEvent(MotionEvent ev) {
    final int action = ev.getAction();
    final int x = (int) ev.getX();
    final int y = (int) ev.getY();  
    
    if ( !mDraggingEnabled ) {
      
      return super.onTouchEvent( ev );
      
    }
    
    
    
    if ( action == MotionEvent.ACTION_DOWN && x >= ( this.getWidth() - mDragHandleWidth ) ) {
      
      mDragMode = true;
      
    }

    if ( !mDragMode ) 
      return super.onTouchEvent( ev );

    
    switch (action) {
      case MotionEvent.ACTION_DOWN:
        mStartPosition = pointToPosition(x,y);
        if (mStartPosition != INVALID_POSITION) {
          int mItemPosition = mStartPosition - getFirstVisiblePosition();
                    mDragPointOffset = y - getChildAt(mItemPosition).getTop();
                    mDragPointOffset -= ((int)ev.getRawY()) - y;
          startDrag(mItemPosition,y);
          drag( 0,y);// replace 0 with x if desired
        }  
        break;
      case MotionEvent.ACTION_MOVE:
        drag(0,y);// replace 0 with x if desired
        break;
      case MotionEvent.ACTION_CANCEL:
      case MotionEvent.ACTION_UP:
      default:
        mDragMode = false;
        mEndPosition = pointToPosition(x,y);
        // Where is the pointToPosition when dragged above?
        
        if ( mEndPosition == INVALID_POSITION && mStartPosition != INVALID_POSITION ) {
          
          if ( getFirstVisiblePosition() == 0 ) { // Above the first
            
            mEndPosition = 0;
            
          } else { // Below the last
            
            mEndPosition = getLastVisiblePosition();
            
          }
          //android.util.Log.i( "DragNDropListView", "First visible: " + getFirstVisiblePosition() );
          
        }
        
        android.util.Log.i( "DragNDropListView", "Dropped: " + mEndPosition );
        
        stopDrag(mStartPosition - getFirstVisiblePosition());
        if (mDropListener != null && mStartPosition != INVALID_POSITION && mEndPosition != INVALID_POSITION) 
               mDropListener.onDrop(mStartPosition, mEndPosition);
        break;
    }
    
    return true;
    
  }  
  
  // move the drag view
  private void drag(int x, int y) {
    
    if (mDragView != null) {
      
      WindowManager.LayoutParams layoutParams = (WindowManager.LayoutParams) mDragView.getLayoutParams();
      layoutParams.x = x;
      layoutParams.y = y - mDragPointOffset;
      WindowManager mWindowManager = (WindowManager) getContext()
          .getSystemService(Context.WINDOW_SERVICE);
      mWindowManager.updateViewLayout(mDragView, layoutParams);
      
      if (mDragListener != null)
        mDragListener.onDrag( x, y, this );// change null to "this" when ready to use
      
    }
    
  }

  // enable the drag view for dragging
  @SuppressLint("NewApi")
  private void startDrag(int itemIndex, int y) {
    
    stopDrag(itemIndex);

    View item = getChildAt(itemIndex);
    if (item == null) return;
    item.setDrawingCacheEnabled(true);
    if (mDragListener != null)
      mDragListener.onStartDrag( itemIndex, item);
    
        // Create a copy of the drawing cache so that it does not get recycled
        // by the framework when the list tries to clean up memory
        Bitmap bitmap = Bitmap.createBitmap(item.getDrawingCache());
        
        item.setDrawingCacheEnabled(false);

        WindowManager.LayoutParams mWindowParams = new WindowManager.LayoutParams();
        mWindowParams.gravity = Gravity.TOP;
        mWindowParams.x = 0;
        mWindowParams.y = y - mDragPointOffset;

        mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
        mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
        mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
                | WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;
        //mWindowParams.format = PixelFormat.OPAQUE;
        mWindowParams.format = PixelFormat.TRANSLUCENT;
        mWindowParams.windowAnimations = 0;
        
        Context context = getContext();
        
        
        ImageView v = new ImageView(context);
        
        v.setImageBitmap(bitmap);      
        v.setBackgroundResource( R.drawable.drag_shadow );
        
        if ( android.os.Build.VERSION.SDK_INT >= 11 ) {
          
          v.setAlpha( 0.8f );
          
        }/* else if ( android.os.Build.VERSION.SDK_INT >= 16 ) {
          
          v.setImageAlpha( (int) 0.8 * 255 );
          
        }
        */
        //LayoutInflater inflater = ( LayoutInflater ) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE );
    //mDragShadow = inflater.inflate( R.layout.list_item_placeholder, null );
        
        WindowManager mWindowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        //mWindowManager.addView( mDragShadow , mWindowParams );
        mWindowManager.addView(v, mWindowParams );
        
        
        
        mDragView = v;
        
  }

  // destroy drag view
  private void stopDrag(int itemIndex) {
    if (mDragView != null) {
      if (mDragListener != null)
        mDragListener.onStopDrag(getChildAt(itemIndex));
            mDragView.setVisibility(GONE);
            WindowManager wm = (WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE);
            wm.removeView(mDragView);
            
            //wm.removeView( mDragShadow );
            // Recycle the backing bitmap!
            BitmapDrawable bd = ( BitmapDrawable ) mDragView.getDrawable();
      
      if ( null != bd && null != bd.getBitmap() ) {
        
        bd.getBitmap().recycle();
        
      }
            
            
            mDragView.setImageDrawable(null);
            mDragView = null;
            //mDragShadow = null;
            
    }
    
  }
  
  private OnScrollListener mScrollListener = new OnScrollListener() {

    @Override public void onScroll( AbsListView view, int firstVisibleItem,
        int visibleItemCount, int totalItemCount) {
      
      //if ( null != mDragShadow ) {
        
        //mDragShadow.setY( );
        
      //}
      android.util.Log.i( "DragNDropListView", "Is scrolling");
      
    }

    @Override public void onScrollStateChanged(AbsListView view, int scrollState) {
      
      
      
    }
    
  };

//  private GestureDetector createFlingDetector() {
//    return new GestureDetector(getContext(), new SimpleOnGestureListener() {
//            @Override
//            public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
//                    float velocityY) {           
//                if (mDragView != null) {                
//                  int deltaX = (int)Math.abs(e1.getX()-e2.getX());
//                  int deltaY = (int)Math.abs(e1.getY() - e2.getY());
//               
//                  if (deltaX > mDragView.getWidth()/2 && deltaY < mDragView.getHeight()) {
//                    mRemoveListener.onRemove(mStartPosition);
//                  }
//                  
//                  stopDrag(mStartPosition - getFirstVisiblePosition());
//
//                    return true;
//                }
//                return false;
//            }
//        });
//  }
}
Java Source Code List
