Android多点触摸事件.rar

package com.practice.imageviewpic; import android.app.Activity; import android.content.Context; import android.graphics.*; import android.graphics.drawable.BitmapDrawable; import android.os.Bundle; import android.view.MotionEvent; import android.widget.ImageView; import android.widget.ImageView.ScaleType; public class ImageViewPic extends Activity { /* * 利用多点触控来控制ImageView中图像的放大与缩小 * 手指控制图片移动 */ private MyImageView imageView; private Bitmap bitmap; //两点触屏后之间的长度 private float beforeLenght; private float afterLenght; //单点移动的前后坐标值 private float afterX,afterY; private float beforeX,beforeY; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); findView(); setContentView(imageView); config(); } private void findView() { imageView = new MyImageView(this); //获得图片 bitmap = ((BitmapDrawable)getResources().getDrawable(R.drawable.xing)).getBitmap(); } private void config() { //设置imageView的显示图片 imageView.setImageBitmap(bitmap); //设置图片填充ImageView imageView.setScaleType(ScaleType.FIT_XY); } //创建一个自己的ImageView类 class MyImageView extends ImageView { private float scale = 0.1f; public MyImageView(Context context) { super(context); } //用来设置ImageView的位置 private void setLocation(int x,int y) { this.setFrame(this.getLeft()+x, this.getTop()+y, this.getRight()+x, this.getBottom()+y); } /* * 用来放大缩小ImageView * 因为图片是填充ImageView的，所以也就有放大缩小图片的效果 * flag为0是放大图片，为1是缩小图片 */ private void setScale(float temp,int flag) { if(flag==0) { this.setFrame(this.getLeft()-(int)(temp*this.getWidth()), this.getTop()-(int)(temp*this.getHeight()), this.getRight()+(int)(temp*this.getWidth()), this.getBottom()+(int)(temp*this.getHeight())); }else { this.setFrame(this.getLeft()+(int)(temp*this.getWidth()), this.getTop()+(int)(temp*this.getHeight()), this.getRight()-(int)(temp*this.getWidth()), this.getBottom()-(int)(temp*this.getHeight())); } } //绘制边框 @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); Rect rec=canvas.getClipBounds(); rec.bottom--; rec.right--; Paint paint=new Paint(); paint.setColor(Color.RED); paint.setStyle(Paint.Style.STROKE); canvas.drawRect(rec, paint); } /* 让图片跟随手指触屏的位置移动 * beforeX、Y是用来保存前一位置的坐标 * afterX、Y是用来保存当前位置的坐标 * 它们的差值就是ImageView各坐标的增加或减少值 */ public void moveWithFinger(MotionEvent event) { switch(event.getAction()) { case MotionEvent.ACTION_DOWN: beforeX = event.getX(); beforeY = event.getY(); break; case MotionEvent.ACTION_MOVE: afterX = event.getX(); afterY = event.getY(); this.setLocation((int)(afterX-beforeX),(int)(afterY-beforeY)); beforeX = afterX; beforeY = afterY; break; case MotionEvent.ACTION_UP: break; } } /* * 通过多点触屏放大或缩小图像 * beforeLenght用来保存前一时间两点之间的距离 * afterLenght用来保存当前时间两点之间的距离 */ public void scaleWithFinger(MotionEvent event) { float moveX = event.getX(1) - event.getX(0); float moveY = event.getY(1) - event.getY(0); switch(event.getAction()) { case MotionEvent.ACTION_DOWN: beforeLenght = (float) Math.sqrt( (moveX*moveX) + (moveY*moveY) ); break; case MotionEvent.ACTION_MOVE: //得到两个点之间的长度 afterLenght = (float) Math.sqrt( (moveX*moveX) + (moveY*moveY) ); float gapLenght = afterLenght - beforeLenght; if(gapLenght == 0) { break; } //如果当前时间两点距离大于前一时间两点距离，则传0，否则传1 if(gapLenght>0) { this.setScale(scale,0); }else { this.setScale(scale,1); } beforeLenght = afterLenght; break; } } } //这里来监听屏幕触控时间 @Override public boolean onTouchEvent(MotionEvent event) { /* * 判定用户是否触摸到了图片 * 如果是单点触摸则调用控制图片移动的方法 * 如果是2点触控则调用控制图片大小的方法 */ if(event.getY() > imageView.getTop() && event.getY() < imageView.getBottom() && event.getX() > imageView.getLeft() && event.getX() < imageView.getRight()) { if(event.getPointerCount() == 2) { imageView.scaleWithFinger(event); }else if(event.getPointerCount() == 1) { imageView.moveWithFinger(event); } } return true; } }