package com.example.aspros.draggridview.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.os.Vibrator;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.widget.GridView;
import com.example.aspros.draggridview.LogUtil;
import com.example.aspros.draggridview.R;
import com.nineoldandroids.animation.Animator;
import com.nineoldandroids.animation.AnimatorSet;
import com.nineoldandroids.animation.ObjectAnimator;
import com.nineoldandroids.animation.TypeEvaluator;
import com.nineoldandroids.animation.ValueAnimator;
import java.util.ArrayList;
import java.util.List;
/**
* Created by aspros on 16/3/18.
*/
public class DragGridView extends GridView
{
private static final int MOVE_DURATION = 300;
private static final int SCROLL_SPEED = 60;
private static final int EXTEND_LENGTH = 20;
private Vibrator vibrator;
private int lastX = -1;
private int lastY = -1;
/**
* 拖动时的图像 和 它的位置
*/
private BitmapDrawable hoverCell;
private Rect currentRect;
/**
* 要拖动的view
*/
private View selectView;
private int originPosition = INVALID_POSITION;
private int currentPosition = INVALID_POSITION;
private boolean isEdit;
private boolean isDrag;
private boolean isSwap;
private DragCallback dragCallback;
public DragGridView(Context context)
{
this(context, null);
}
public DragGridView(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
public DragGridView(Context context, AttributeSet attrs, int defStyleAttr)
{
super(context, attrs, defStyleAttr);
vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
}
public DragAdapterInterface getInterface()
{
return (DragAdapterInterface) getAdapter();
}
public void setDragCallback(DragCallback dragCallback)
{
this.dragCallback=dragCallback;
}
@Override
public boolean onTouchEvent(MotionEvent ev)
{
int x = (int) ev.getX();
int y = (int) ev.getY();
switch (ev.getAction())
{
case MotionEvent.ACTION_DOWN:
lastX = x;
lastY = y;
break;
case MotionEvent.ACTION_MOVE:
if (isDrag)
{
int offsetX = x - lastX;
int offsetY = y - lastY;
lastX = x;
lastY = y;
currentRect.offset(offsetX, offsetY);
hoverCell.setBounds(currentRect);
invalidate();
if (!isSwap)
{
swapItems(x, y);
}
handleScroll();
return false;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
if (isDrag)
{
endDrag();
}
break;
default:
}
return super.onTouchEvent(ev);
}
public void clicked(int position)
{
if(isEdit)
{
isEdit=false;
return;
}
resumeView();
LogUtil.i("点击 Item " + position);
}
private void resumeView()
{
if (selectView != null)
{
selectView.findViewById(R.id.delete_img).setVisibility(INVISIBLE);
selectView.findViewById(R.id.item_container).setVisibility(VISIBLE);
selectView.findViewById(R.id.item_container).setBackgroundColor(Color.WHITE);
}
}
public void startDrag(int position)
{
if (position == INVALID_POSITION)
{
return;
}
//恢复之前的图像,改变背景,去除删除按钮
resumeView();
selectView = getChildAt(position - getFirstVisiblePosition());
if (selectView != null)
{
isDrag = true;
isEdit = true;
/**
* 移动的图像背景要有区别,并显示删除按钮
*/
selectView.findViewById(R.id.item_container).setBackgroundColor(Color.parseColor("#f0f0f0"));
selectView.findViewById(R.id.delete_img).setVisibility(VISIBLE);
originPosition = position;
currentPosition = position;
vibrator.vibrate(60);
//获取图像
hoverCell = getHoverCell(selectView);
selectView.findViewById(R.id.item_container).setVisibility(INVISIBLE);
if(dragCallback!=null)
{
dragCallback.startDrag(position);
}
}
}
private void swapItems(int x, int y)
{
int endPosition = pointToPosition(x, y);
if (endPosition != INVALID_POSITION && endPosition != currentPosition)
{
isSwap = true;
isEdit = false;
resumeView();
//交换数据内容
getInterface().reOrder(currentPosition, endPosition);
selectView=getChildAt(endPosition-getFirstVisiblePosition());
selectView.findViewById(R.id.item_container).setVisibility(INVISIBLE);
selectView.findViewById(R.id.item_container).setBackgroundColor(Color.parseColor("#f0f0f0"));
selectView.findViewById(R.id.delete_img).setVisibility(VISIBLE);
//动画显示交换过程
animateSwap(endPosition);
}
}
private void animateSwap(int endPosition)
{
List<Animator> animators=new ArrayList<>();
if(endPosition<currentPosition)
{
for(int i=endPosition+1;i<=currentPosition;i++)
{
View view=getChildAt(i-getFirstVisiblePosition());
if(i%getNumColumns()==0)
{
animators.add(createTranslationAnimations(view,view.getWidth()*(getNumColumns()-1),0,-view.getHeight(),0));
}
else
{
animators.add(createTranslationAnimations(view,-view.getWidth(),0,0,0));
}
}
}
else
{
for(int i=currentPosition;i<endPosition;i++)
{
View view=getChildAt(i-getFirstVisiblePosition());
if((i+1)%getNumColumns()==0)
{
animators.add(createTranslationAnimations(view,-view.getWidth()*(getNumColumns()-1),0,view.getHeight(),0));
}
else
{
animators.add(createTranslationAnimations(view,view.getWidth(),0,0,0));
}
}
}
currentPosition=endPosition;
AnimatorSet animatorSet=new AnimatorSet();
animatorSet.playTogether(animators);
animatorSet.setDuration(MOVE_DURATION);
animatorSet.setInterpolator(new AccelerateDecelerateInterpolator());
animatorSet.addListener(new Animator.AnimatorListener()
{
@Override
public void onAnimationStart(Animator animation)
{
}
@Override
public void onAnimationEnd(Animator animation)
{
isSwap = false;
}
@Override
public void onAnimationCancel(Animator animation)
{
}
@Override
public void onAnimationRepeat(Animator animation)
{
}
});
animatorSet.start();
}
private Animator createTranslationAnimations(View view, float startX, float endX, float startY, float endY)
{
ObjectAnimator animX = ObjectAnimator.ofFloat(view, "translationX", startX, endX);
ObjectAnimator animY = ObjectAnimator.ofFloat(view, "translationY", startY, endY);
AnimatorSet animSetXY = new AnimatorSet();
animSetXY.playTogether(animX, animY);
return animSetXY;
}
private void endDrag()
{
currentRect.set(selectView.getLeft(), selectView.getTop(), selectView.getRight(), selectView.getBottom());
animateBound();
}
private void animateBound()
{
TypeEvaluator<Rect> evaluator = new TypeEvaluator<Rect>()
{
@Override
public Rect evaluate(float fraction, Rect startValue, Rect endValue)
{
return new Rect(interpolate(startValue.left, endValue.left, fraction),
interpolate(startValue.top, endValue.top, fraction),
interpolate(startValue.right, endValue.right, fraction),
interpolate(startValue.bottom, endValue.bottom, fraction));
}
public int interpolate(int start, int end, float fraction)
{
return (int) (start + fraction * (end - start));
}
};
ObjectAnimator animator = ObjectAnimator.ofObject(hoverCell, "bounds", evaluator, currentRect);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
{
@Override
public void onAnimationUpdate(ValueAnimator animation)
{
invalidate();
}
});
animator.addListener(new Animator.AnimatorListener()
{
@Override
public void onAnimationStart(Animator animation)
{
}
@Override
public void onAnimationEnd(Animator animation)
{
isDrag = false;
if (currentPosition != originPosition)
{
resumeView();
originPosition = currentPosition;
}
hoverCell = null;
selectView.findViewById(R.id.item_container).setVisibility(VISIBLE);
if (dragCallback != null)
{
dragCallback.endDrag(currentPosition);
}
}
@Override
public void onAnimationCancel(Animator animation)
{
}
@Override
public void onAnimationRepeat(Animator animation)
{
}
});
animator.start();
}
private BitmapDrawable getHoverCell(View view)
{
int left = view.getLeft();
int top = view.getTop();
int w = view.getWidth();
int h = view.getHeight();
Bitmap bitmap = getBitmapFromView(view);
BitmapDrawable drawable = new BitmapDrawable(getResources(), bitmap);
currentRect = new Rect(left - EXTEND_LENGTH, top - EXTEND_LENGTH, left + w + EXTEND_LENGTH, top + h + EXTEND_LENGTH);
drawable.setBounds(currentRect);
return drawable;
}
private Bitmap getBitmapFromView(View v)
{
Bitmap bitmap = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
v.draw(canvas);
return bitmap;
}
private void handleScroll()
{
int offset=computeVerticalScrollOffset();
int height=getHeight();
int extent=computeVerticalScrollExtent();
int range=computeHorizontalScrollRange();
if(currentRect.top<=0 && offset>0)
{
smoothScrollBy(-SCROLL_SPEED,0);
}
else
if(currentRect.bottom>=height && (offset+extent)<range)
{
smoothScrollBy(SCROLL_SPEED,0);
}
}
@Override
protected void dispatchDraw(Canvas canvas)
{
super.dispatchDraw(canvas);
if (hoverCell != null)
{
hoverCell.draw(canvas);
}
}
}
