一、RotatView

package com.sun.shine.myrotation.view;import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.SurfaceView;
import android.view.View;public class RotatView extends View {float o_x;float o_y;Handler handler;int delayedTime = 20;static final int play = 0;static final int stop = 1;double currentTime = 0;int width;int height;double maxwidth;Bitmap rotatBitmap;public RotatView(Context context, AttributeSet attrs) {super(context, attrs);init();}private void init() {vRecord = new VRecord();handler = new Handler() {@Overridepublic void handleMessage(Message msg) {double detaTime = System.currentTimeMillis() - currentTime;switch (msg.what) {case play: {if (isClockWise) {speed = speed - a * detaTime;if (speed <= 0) {return;} else {handler.sendEmptyMessageDelayed(play, delayedTime);}} else {speed = speed + a * detaTime;if (speed >= 0) {return;} else {handler.sendEmptyMessageDelayed(play, delayedTime);}}addDegree((float)(speed * detaTime + (a * detaTime * detaTime) / 2));// if (a < a_max) {// a = (float)(a + a_add*detaTime);// System.out.println("a:"+a);// }currentTime = System.currentTimeMillis();invalidate();break;}case stop: {speed = 0;handler.removeMessages(play);}}super.handleMessage(msg);}};initSize();}public void setRotatBitmap(Bitmap bitmap) {rotatBitmap = bitmap;initSize();postInvalidate();}public void setRotatDrawableResource(int id) {BitmapDrawable drawable = (BitmapDrawable)getContext().getResources().getDrawable(id);setRotatDrawable(drawable);}public void setRotatDrawable(BitmapDrawable drawable) {rotatBitmap = drawable.getBitmap();initSize();postInvalidate();}private void initSize() {if (rotatBitmap == null) {// throw new NoBitMapError("Error,No bitmap in RotatView!");return;}width = rotatBitmap.getWidth();height = rotatBitmap.getHeight();maxwidth = Math.sqrt(width * width + height * height);o_x = o_y = (float)(maxwidth / 2);// ȷ��Բ�����}private void addDegree(float added) {deta_degree += added;if (deta_degree > 360 || deta_degree < -360) {deta_degree = deta_degree % 360;}}@Overrideprotected void onDraw(Canvas canvas) {Matrix matrix = new Matrix();matrix.setTranslate((float)width / 2, (float)height / 2);matrix.preRotate(deta_degree);matrix.preTranslate(-(float)width / 2, -(float)height / 2);matrix.postTranslate((float)(maxwidth - width) / 2, (float)(maxwidth - height) / 2);canvas.drawBitmap(rotatBitmap, matrix, paint);super.onDraw(canvas);}Paint paint = new Paint();@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {// TODO Auto-generated method stubsuper.onMeasure(widthMeasureSpec, heightMeasureSpec);setMeasuredDimension((int)maxwidth, (int)maxwidth);}float down_x;float down_y;float target_x;float target_y;float up_x;float up_y;float current_degree;float up_degree;float deta_degree;double lastMoveTime = 0;public static final float a_min = 0.001f;public static final float a_add = 0.001f;float a = a_min;public static final float a_max = a_min * 5;double speed = 0;VRecord vRecord;boolean isClockWise;@Overridepublic boolean onTouchEvent(MotionEvent event) {// TODO Auto-generated method stubif (rotatBitmap == null) {throw new NoBitMapError("Error,No bitmap in RotatView!");}switch (event.getAction()) {case MotionEvent.ACTION_DOWN: {down_x = event.getX();down_y = event.getY();current_degree = detaDegree(o_x, o_y, down_x, down_y);vRecord.reset();// handler.sendEmptyMessage(stop);a = a_max;break;}case MotionEvent.ACTION_MOVE: {down_x = target_x = event.getX();down_y = target_y = event.getY();float degree = detaDegree(o_x, o_y, target_x, target_y);float dete = degree - current_degree;if (dete < -270) {dete = dete + 360;} else if (dete > 270) {dete = dete - 360;}lastMoveTime = System.currentTimeMillis();vRecord.add(dete, lastMoveTime);addDegree(dete);current_degree = degree;postInvalidate();break;}case MotionEvent.ACTION_CANCEL:case MotionEvent.ACTION_UP: {a = a_min;double lastupTime = System.currentTimeMillis();double detaTime = lastupTime - lastMoveTime;up_x = event.getX();up_y = event.getY();up_degree = detaDegree(o_x, o_y, up_x, up_y);speed = speed + vRecord.getSpeed();if (speed > 0) {speed = Math.min(VRecord.max_speed, speed);} else {speed = Math.max(-VRecord.max_speed, speed);}// System.out.println("speed:" + speed);if (speed > 0) {isClockWise = true;// v = 1;} else {isClockWise = false;// v = -1;}currentTime = System.currentTimeMillis();handler.sendEmptyMessage(0);break;}}return true;}float detaDegree(float src_x, float src_y, float target_x, float target_y) {float detaX = target_x - src_x;float detaY = target_y - src_y;double d;if (detaX != 0) {float tan = Math.abs(detaY / detaX);if (detaX > 0) {if (detaY >= 0) {d = Math.atan(tan);} else {d = 2 * Math.PI - Math.atan(tan);}} else {if (detaY >= 0) {d = Math.PI - Math.atan(tan);} else {d = Math.PI + Math.atan(tan);}}} else {if (detaY > 0) {d = Math.PI / 2;} else {d = -Math.PI / 2;}}return (float)((d * 180) / Math.PI);}static class NoBitMapError extends RuntimeException {/*** */private static final long serialVersionUID = 1L;public NoBitMapError(String detailMessage) {super(detailMessage);}}static class VRecord {int addCount;public static final int length = 15;double[][] record = new double[length][2];public void add(double detadegree, double time) {for (int i = length - 1; i > 0; i--) {record[i][0] = record[i - 1][0];record[i][1] = record[i - 1][1];}record[0][0] = detadegree;record[0][1] = time;addCount++;}public static final double max_speed = 8;public double getSpeed() {if (addCount == 0) {return 0;}int maxIndex = Math.min(addCount, length) - 1;if ((record[0][1] - record[maxIndex][1]) == 0) {return 0;}double detaTime = record[0][1] - record[maxIndex][1];double sumdegree = 0;for (int i = 0; i < length - 1; i++) {sumdegree += record[i][0];// System.out.println(record[i][0]);}// System.out.println("----------");// System.out.println(sumdegree);// System.out.println(detaTime);double result = sumdegree / detaTime;if (result > 0) {return Math.min(result, max_speed);} else {return Math.max(result, -max_speed);}// System.out.println("v=" + result);}public void reset() {addCount = 0;for (int i = length - 1; i > 0; i--) {record[i][0] = 0;record[i][1] = 0;}}}@Overrideprotected void onDetachedFromWindow() {super.onDetachedFromWindow();if (rotatBitmap != null) {rotatBitmap.recycle();rotatBitmap = null;}}
}

二、MainActivity

package com.sun.shine.myrotation;import com.sun.shine.myrotation.view.RotatView;import android.os.Bundle;
import android.app.Activity;public class MainActivity extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);RotatView rotatView=(RotatView)findViewById(R.id.myRotatView);rotatView.setRotatDrawableResource(R.drawable.cycle);}}