Android實現圖片隨手指旋轉功能

在View中進行重繪，主要是通過計算角度及距離來實現。實現類代碼如下：

package com.example.roatedemo;

import java.util.Calendar;
import Android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

public class RotateView extends View {
private Paint mPaint = new Paint();
private Bitmap bitmaplittele;//中間不動的圖片
private Bitmap bitmapBig;//隨手指轉動的圖片
private Bitmap bitmapOut;//外圍不動的圖片
// 圓心坐標
private float mPointX = 0, mPointY = 0;

private int flag = 0;
// 半徑
private int mRadius = 0;
// 旋轉角度
private int mAngle = 0;
private int beginAngle = 0, currentAngle = 0;
private String TAG = "NewView";
int bitMap[] = { R.drawable.circle0, R.drawable.circle1, R.drawable.circle2 };
int imageIndex = 0;
boolean isUp = false,isTouch=false;
Context mContext;
RotateViewListener listener;
long beginTime,endTime;
Calendar now;

public RotateView(Context context, int px, int py, int radius,RotateViewListener listener) {
super(context);
mContext = context;
this.listener = listener;
mPointX = px;
mPointY = py;
mRadius = radius;
bitmaplittele = BitmapFactory.decodeResource(getResources(),
R.drawable.a1_pointer).copy(Bitmap.Config.ARGB_8888, true);
bitmapBig = BitmapFactory.decodeResource(getResources(), bitMap[0])
.copy(Bitmap.Config.ARGB_8888, true);
bitmapOut = BitmapFactory.decodeResource(getResources(),
R.drawable.bigcir).copy(Bitmap.Config.ARGB_8888, true);
setBackgroundResource(R.drawable.back);
Log.e(TAG, "RotateViewBegin");
}

@Override
public boolean dispatchTouchEvent(MotionEvent e) {
switch (e.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
now = Calendar.getInstance();
beginTime = now.getTimeInMillis();
beginAngle = computeCurrentAngle(e.getX(), e.getY());
isUp = false;
//如果點擊觸摸范圍在圈外，則不處理
if (getDistance(e.getX(), e.getY())>bitmapOut.getWidth()/2) {
isTouch=false;
}else {
isTouch=true;
}
return true;
case MotionEvent.ACTION_MOVE:
if (!isTouch) {
return true;
}
currentAngle = computeCurrentAngle(e.getX(), e.getY());
invalidate();
return true;
case MotionEvent.ACTION_UP:
isUp = true;
if (!isTouch) {
return true;
}
now = Calendar.getInstance();
endTime = now.getTimeInMillis();
if (SetClick(e.getX(), e.getY())) {
return true;
}
if (mAngle > 0) {
int count = mAngle / 120 + (mAngle % 120 > 60 ? 1 : 0);
imageIndex = (imageIndex + count) % 3;
} else if (mAngle < 0) {
mAngle = -mAngle;
int count = mAngle / 120 + (mAngle % 120 > 60 ? 1 : 0);
imageIndex = (imageIndex + 3 - count) % 3;
}
bitmapBig = BitmapFactory.decodeResource(getResources(),
bitMap[imageIndex]).copy(Bitmap.Config.ARGB_8888, true);
bitmapBig = adjustPhotoRotation(bitmapBig, imageIndex * 120);
invalidate();
if (mAngle >= 60) {
listener.onModChange(imageIndex);
}
return true;
}

return false;
}

@Override
public void onDraw(Canvas canvas) {
// Log.i(TAG, "onDraw");
// 大圓
drawInCenter(canvas, bitmapOut, mPointX, mPointY, TAG);
// 外圈
if (isUp) {
mAngle = 0;
} else {
mAngle = currentAngle - beginAngle;
}

Bitmap tempBig = adjustPhotoRotation(bitmapBig, mAngle);
// Log.i(TAG, "mAngle:"+mAngle);
drawInCenter(canvas, tempBig, mPointX, mPointY + 10, TAG);
// 小圓(中間的圓心)
drawInCenter(canvas, bitmaplittele, mPointX, mPointY - 10, TAG);
}

Bitmap adjustPhotoRotation(Bitmap bm, final int orientationDegree) {
if (orientationDegree == 0) {
return bm;
}
Matrix m = new Matrix();
m.setRotate(orientationDegree, (float) bm.getWidth() / 2,
(float) bm.getHeight() / 2);

try {
Bitmap bm1 = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(),
bm.getHeight(), m, true);

return bm1;

} catch (OutOfMemoryError ex) {
}

return null;

}

private void drawInCenter(Canvas canvas, Bitmap bitmap, float left,
float top, String text) {
canvas.drawBitmap(bitmap, left - bitmap.getWidth() / 2,
top - bitmap.getHeight() / 2, null);
}

// 子控件位置改變重新計算角度
private int computeCurrentAngle(float x, float y) {
// 根據圓心坐標計算角度
float distance = (float) Math
.sqrt(((x - mPointX) * (x - mPointX) + (y - mPointY)
* (y - mPointY)));
int degree = (int) (Math.acos((x - mPointX) / distance) * 180 / Math.PI);
if (y < mPointY) {
degree = -degree;
}
if (degree < 0) {
degree += 360;
}

// Log.i("RoundSpinView", "x:" + x + ",y:" + y + ",degree:" + degree);
return degree;
}

// 獲取距離圓心的距離
private float getDistance(float x, float y) {
// 根據圓心坐標計算角度
float distance = (float) Math
.sqrt(((x - mPointX) * (x - mPointX) + (y - mPointY)
* (y - mPointY)));
return distance;
}

//點擊
private boolean SetClick(float x, float y) {
float distance = getDistance(x, y);
if (mAngle>10||mAngle<-10) {
return false;
}else if(endTime-beginTime>1000){
return false;
}
if (distance < bitmapBig.getWidth() / 2) {
int mod = 0;

if (beginAngle < 90 || 330 < beginAngle) {
mod = (imageIndex+3-1)%3;
}
else if (90 < beginAngle && 210 > beginAngle) {
mod = (imageIndex+3-2)%3;
}
else{
mod = imageIndex;
}
//回調到主界面進行處理。
listener.onModClick(mod);
}
return true;
}

public interface RotateViewListener {
void onModClick(int mode);
void onModChange(int mode);
}
}