[android]使用 Matrix 的随触摸旋转的ImageView
package com.lurencun.poolotools.ui.light;import android.content.Context;import android.graphics.Canvas;import android.graphics.Matrix;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.widget.ImageView;/** * 随触摸旋转ImageView * * @author liupoolo * @since 2013-02-22 * @version 1.00 */public class TouchRoateImageView extends ImageView {private final static float MIN_DEGREE = 0f;private final static float MAX_DEGREE = 360f;private Matrix m;private float saveX; // 当前保存的xprivate float saveY; // 当前保存的yprivate float curTouchX; // 当前触屏的xprivate float curTouchY; // 当前触摸的yprivate float centerX; // 中心点xprivate float centerY; // 中心点yprivate float curDegree; // 当前角度private float changeDegree;public TouchRoateImageView(Context context, AttributeSet attrs) {super(context, attrs);setScaleType(ScaleType.MATRIX);// 重点m = new Matrix();}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);centerX = this.getWidth() / 2;centerY = this.getHeight() / 2;}public boolean onTouchEvent(MotionEvent event) {handleTouch(event);return true;}private void handleTouch(MotionEvent event) {curTouchX = event.getX();curTouchY = event.getY();switch (event.getAction()) {case MotionEvent.ACTION_DOWN:saveTouchPoint();break;case MotionEvent.ACTION_MOVE:handleTouchMove();break;case MotionEvent.ACTION_UP:// 可以使用访问者模式这里让访问者获得当前角度break;}}private void handleTouchMove() {changeDegree = (float) getActionDegrees(centerX, centerY, saveX, saveY,curTouchX, curTouchY);float tempDegree = (float) curDegree + changeDegree;if (tempDegree >= MIN_DEGREE && tempDegree <= MAX_DEGREE) {optimize(tempDegree);//优化变动m.setRotate(curDegree, centerX, centerY);setImageMatrix(m);// 此方法会 调用invalidate() 从而重绘界面}saveTouchPoint();}private void optimize(float tempDegree){if(tempDegree>MAX_DEGREE-1){curDegree=MAX_DEGREE;}else if(tempDegree<MIN_DEGREE+1){curDegree=MIN_DEGREE;}else{this.curDegree = tempDegree;}}private void saveTouchPoint() {saveX = curTouchX;saveY = curTouchY;}/** * 获取两点到第三点的夹角。 * * @param x * @param y * @param x1 * @param y1 * @param x2 * @param y2 * @return */private double getActionDegrees(float x, float y, float x1, float y1,float x2, float y2) {double a = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));double b = Math.sqrt((x - x2) * (x - x2) + (y - y2) * (y - y2));double c = Math.sqrt((x1 - x) * (x1 - x) + (y1 - y) * (y1 - y));// 余弦定理double cosA = (b * b + c * c - a * a) / (2 * b * c);// 返回余弦值为指定数字的角度，Math函数为我们提供的方法double arcA = Math.acos(cosA);double degree = arcA * 180 / Math.PI;// 接下来我们要讨论正负值的关系了，也就是求出是顺时针还是逆时针。// 第1、2象限if (y1 < y && y2 < y) {if (x1 < x && x2 > x) {// 由2象限向1象限滑动return degree;}// 由1象限向2象限滑动else if (x1 >= x && x2 <= x) {return -degree;}}// 第3、4象限if (y1 > y && y2 > y) {// 由3象限向4象限滑动if (x1 < x && x2 > x) {return -degree;}// 由4象限向3象限滑动else if (x1 > x && x2 < x) {return degree;}}// 第2、3象限if (x1 < x && x2 < x) {// 由2象限向3象限滑动if (y1 < y && y2 > y) {return -degree;}// 由3象限向2象限滑动else if (y1 > y && y2 < y) {return degree;}}// 第1、4象限if (x1 > x && x2 > x) {// 由4向1滑动if (y1 > y && y2 < y) {return -degree;}// 由1向4滑动else if (y1 < y && y2 > y) {return degree;}}// 在特定的象限内float tanB = (y1 - y) / (x1 - x);float tanC = (y2 - y) / (x2 - x);if ((x1 > x && y1 > y && x2 > x && y2 > y && tanB > tanC)// 第一象限|| (x1 > x && y1 < y && x2 > x && y2 < y && tanB > tanC)// 第四象限|| (x1 < x && y1 < y && x2 < x && y2 < y && tanB > tanC)// 第三象限|| (x1 < x && y1 > y && x2 < x && y2 > y && tanB > tanC))// 第二象限return -degree;return degree;}public float getCurDegree() {return curDegree;}public void setCurDegree(float curDegree) {if (curDegree >= MIN_DEGREE && curDegree <= MAX_DEGREE) {this.curDegree = curDegree;m.setRotate(curDegree, centerX, centerY);setImageMatrix(m);}}}
?
