package com.roboo.like.netease.view;
import com.roboo.like.netease.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.os.Handler;
import android.os.Vibrator;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.ImageView;
/**
* @blog http://blog.csdn.net/xiaanming
*
* @author xiaanming
*
*/
@SuppressLint("NewApi")
public class DragGridView extends GridView
{
/**
* DragGridView的item长按响应的时间， 默认是1000毫秒，也可以自行设置
*/
private long dragResponseMS = 1000;
/**
* 是否可以拖拽，默认不可以
*/
private boolean isDrag = false;
private int mDownX;
private int mDownY;
private int moveX;
private int moveY;
/**
* 正在拖拽的position
*/
private int mDragPosition;
/**
* 刚开始拖拽的item对应的View
*/
private View mStartDragItemView = null;
/**
* 用于拖拽的镜像，这里直接用一个ImageView
*/
private ImageView mDragImageView;
/**
* 震动器
*/
private Vibrator mVibrator;
private WindowManager mWindowManager;
/**
* item镜像的布局参数
*/
private WindowManager.LayoutParams mWindowLayoutParams;
/**
* 我们拖拽的item对应的Bitmap
*/
private Bitmap mDragBitmap;
/**
* 按下的点到所在item的上边缘的距离
*/
private int mPoint2ItemTop;
/**
* 按下的点到所在item的左边缘的距离
*/
private int mPoint2ItemLeft;
/**
* DragGridView距离屏幕顶部的偏移量
*/
private int mOffset2Top;
/**
* DragGridView距离屏幕左边的偏移量
*/
private int mOffset2Left;
/**
* 状态栏的高度
*/
private int mStatusHeight;
/**
* DragGridView自动向下滚动的边界值
*/
private int mDownScrollBorder;
/**
* DragGridView自动向上滚动的边界值
*/
private int mUpScrollBorder;
/**
* DragGridView自动滚动的速度
*/
private static final int speed = 80;
/**
* item发生变化回调的接口
*/
private OnChanageListener onChanageListener;
public DragGridView(Context context)
{
this(context, null);
}
public DragGridView(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
public DragGridView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
mStatusHeight = getStatusHeight(context); // 获取状态栏的高度
}
private Handler mHandler = new Handler();
// 用来处理是否为长按的Runnable
private Runnable mLongClickRunnable = new Runnable()
{
@Override
public void run()
{
isDrag = true; // 设置可以拖拽
mVibrator.vibrate(50); // 震动一下
mStartDragItemView.setVisibility(View.INVISIBLE);// 隐藏该item
// 根据我们按下的点显示item镜像
createDragImage(mDragBitmap, mDownX, mDownY);
}
};
/**
* 设置回调接口
*
* @param onChanageListener
*/
public void setOnChangeListener(OnChanageListener onChanageListener)
{
this.onChanageListener = onChanageListener;
}
/**
* 设置响应拖拽的毫秒数，默认是1000毫秒
*
* @param dragResponseMS
*/
public void setDragResponseMS(long dragResponseMS)
{
this.dragResponseMS = dragResponseMS;
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev)
{
switch (ev.getAction())
{
case MotionEvent.ACTION_DOWN:
// 使用Handler延迟dragResponseMS执行mLongClickRunnable
mHandler.postDelayed(mLongClickRunnable, dragResponseMS);
mDownX = (int) ev.getX();
mDownY = (int) ev.getY();
// 根据按下的X,Y坐标获取所点击item的position
mDragPosition = pointToPosition(mDownX, mDownY);
if (mDragPosition == AdapterView.INVALID_POSITION)
{
return super.dispatchTouchEvent(ev);
}
// 根据position获取该item所对应的View
mStartDragItemView = getChildAt(mDragPosition - getFirstVisiblePosition());
// 下面这几个距离大家可以参考我的博客上面的图来理解下
mPoint2ItemTop = mDownY - mStartDragItemView.getTop();
mPoint2ItemLeft = mDownX - mStartDragItemView.getLeft();
mOffset2Top = (int) (ev.getRawY() - mDownY);
mOffset2Left = (int) (ev.getRawX() - mDownX);
// 获取DragGridView自动向上滚动的偏移量，小于这个值，DragGridView向下滚动
mDownScrollBorder = getHeight() / 4;
// 获取DragGridView自动向下滚动的偏移量，大于这个值，DragGridView向上滚动
mUpScrollBorder = getHeight() * 3 / 4;
// 开启mDragItemView绘图缓存
mStartDragItemView.setDrawingCacheEnabled(true);
// 获取mDragItemView在缓存中的Bitmap对象
// mDragBitmap = Bitmap.createBitmap(mStartDragItemView.getDrawingCache());
mDragBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_netease_logo);
// 这一步很关键，释放绘图缓存，避免出现重复的镜像
mStartDragItemView.destroyDrawingCache();
break;
case MotionEvent.ACTION_MOVE:
int moveX = (int) ev.getX();
int moveY = (int) ev.getY();
// 如果我们在按下的item上面移动，只要不超过item的边界我们就不移除mRunnable
if (!isTouchInItem(mStartDragItemView, moveX, moveY))
{
mHandler.removeCallbacks(mLongClickRunnable);
}
break;
case MotionEvent.ACTION_UP:
mHandler.removeCallbacks(mLongClickRunnable);
mHandler.removeCallbacks(mScrollRunnable);
break;
}
return super.dispatchTouchEvent(ev);
}
/**
* 是否点击在GridView的item上面
*
* @param itemView
* @param x
* @param y
* @return
*/
private boolean isTouchInItem(View dragView, int x, int y)
{
int leftOffset = dragView.getLeft();
int topOffset = dragView.getTop();
if (x < leftOffset || x > leftOffset + dragView.getWidth())
{
return false;
}
if (y < topOffset || y > topOffset + dragView.getHeight())
{
return false;
}
return true;
}
@Override
public boolean onTouchEvent(MotionEvent ev)
{
if (isDrag && mDragImageView != null)
{
switch (ev.getAction())
{
case MotionEvent.ACTION_MOVE:
moveX = (int) ev.getX();
moveY = (int) ev.getY();
// 拖动item
onDragItem(moveX, moveY);
break;
case MotionEvent.ACTION_UP:
onStopDrag();
isDrag = false;
break;
}
return true;
}
return super.onTouchEvent(ev);
}
/**
* 创建拖动的镜像
*
* @param bitmap
* @param downX
* 按下的点相对父控件的X坐标
* @param downY
* 按下的点相对父控件的X坐标
*/
private void createDragImage(Bitmap bitmap, int downX, int downY)
{
mWindowLayoutParams = new WindowManager.LayoutParams();
mWindowLayoutParams.format = PixelFormat.TRANSLUCENT; // 图片之外的其他地方透明
mWindowLayoutParams.gravity = Gravity.TOP | Gravity.LEFT;
mWindowLayoutParams.x = downX - mPoint2ItemLeft + mOffset2Left;
mWindowLayoutParams.y = downY - mPoint2ItemTop + mOffset2Top - mStatusHeight;
mWindowLayoutParams.alpha = 0.55f; // 透明度
mWindowLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;
mDragImageView = new ImageView(getContext());
mDragImageView.setImageBitmap(bitmap);
mWindowManager.addView(mDragImageView, mWindowLayoutParams);
}
/**
* 从界面上面移动拖动镜像
*/
private void removeDragImage()
{
if (mDragImageView != null)
{
mWindowManager.removeView(mDragImageView);
mDragImageView = null;
}
}
/**
* 拖动item，在里面实现了item镜像的位置更新，item的相互交换以及GridView的自行滚动
*
* @param x
* @param y
*/
private void onDragItem(int moveX, int moveY)
{
mWindowLayoutParams.x = moveX - mPoint2ItemLeft + mOffset2Left;
mWindowLayoutParams.y = moveY - mPoint2ItemTop + mOffset2Top - mStatusHeight;
mWindowManager.updateViewLayout(mDragImageView, mWindowLayoutParams); // 更新镜像的位置
onSwapItem(moveX, moveY);
// GridView自动滚动
mHandler.post(mScrollRunnable);
}
/**
* 当moveY的值大于向上滚动的边界值，触发GridView自动向上滚动 当moveY的值小于向下滚动的边界值，触犯GridView自动向下滚动
* 否则不进行滚动
*/
private Runnable mScrollRunnable = new Runnable()
{
@Override
public void run()
{
int scrollY;
if (moveY > mUpScrollBorder)
{
scrollY = -speed;
mHandler.postDelayed(mScrollRunnable, 25);
}
else if (moveY < mDownScrollBorder)
{
scrollY = speed;
mHandler.postDelayed(mScrollRunnable, 25);
}
else
{
scrollY = 0;
mHandler.removeCallbacks(mScrollRunnable);
}
// 当我们的手指到达GridView向上或者向下滚动的偏移量的时候，可能我们手指没有移动，但是DragGridView在自动的滚动
// 所以我们在这里调用下onSwapItem()方法来交换item
onSwapItem(moveX, moveY);
View view = getChildAt(mDragPosition - getFirstVisiblePosition());
// 实现GridView的自动滚动
smoothScrollToPositionFromTop(mDragPosition, view.getTop() + scrollY);
}
};
/**
* 交换item,并且控制item之间的显示与隐藏效果
*
* @param moveX
* @param moveY
*/
private void onSwapItem(int moveX, int moveY)
{
// 获取我们手指移动到的那个item的position
int tempPosition = pointToPosition(moveX, moveY);
// 假如tempPosition 改变了并且tempPosition不等于-1,则进行交换
if (tempPosition != mDragPosition && tempPosition != AdapterView.INVALID_POSITION)
{
getChildAt(tempPosition - getFirstVisiblePosition()).setVisibility(View.INVISIBLE);// 拖动到了新的item,新的item隐藏掉
getChildAt(mDragPosition - getFirstVisiblePosition()).setVisibility(View.VISIBLE);// 之前的item显示出来
if (onChanageListener != null)
{
onChanageListener.onChange(mDragPosition, tempPosition);
}
mDragPosition = tempPosition;
}
}
/**
* 停止拖拽我们将之前隐藏的item显示出来，并将镜像移除
*/
private void onStopDrag()
{
getChildAt(mDragPosition - getFirstVisiblePosition()).setVisibility(View.VISIBLE);
removeDragImage();
}
/**
* 获取状态栏的高度
*
* @param context
* @return
*/
private static int getStatusHeight(Context context)
{
int statusHeight = 0;
Rect localRect = new Rect();
((Activity) context).getWindow().getDecorView().getWindowVisibleDisplayFrame(localRect);
statusHeight = localRect.top;
if (0 == statusHeight)
{
Class<?> localClass;
try
{
localClass = Class.forName("com.android.internal.R$dimen");
Object localObject = localClass.newInstance();
int i5 = Integer.parseInt(localClass.getField("status_bar_height").get(localObject).toString());
statusHeight = context.getResources().getDimensionPixelSize(i5);
}
catch (Exception e)
{
e.printStackTrace();
}
}
return statusHeight;
}
/**
*
* @author xiaanming
*
*/
public interface OnChanageListener
{
/**
* 当item交换位置的时候回调的方法，我们只需要在该方法中实现数据的交换即可
*
* @param form
* 开始的position
* @param to
* 拖拽到的position
*/
public void onChange(int form, int to);
}
}