Android简单的圆盘形菜单
Android简单的圆盘形菜单
今天偶然看到一个圆盘形的菜单,还可以转动,感觉挺有意思,然后想了想,做了个简单的效果。
思路是这样的,定一个原点和一个半径,圆的四周均匀分布每个菜单。为了方便计算,菜单的坐标用度数表示,然后转化为极坐标计算。
定某个点为起始点,根据总菜单数确定每个点增加的度数,然后依次确定每个点的度数,也就确定了坐标。
- package chroya.demo.roundspin;
- import Android.content.Context;
- import android.graphics.Bitmap;
- import android.graphics.BitmapFactory;
- import android.graphics.Canvas;
- import android.graphics.Color;
- import android.graphics.Paint;
- import android.util.Log;
- import android.view.MotionEvent;
- import android.view.View;
- /**
- * 圆盘式的view
- * @author chroya
- *
- */
- public class RoundSpinView extends View {
- private Paint mPaint = new Paint();
- //stone列表
- private BigStone[] mStones;
- //数目
- private static final int STONE_COUNT = 6;
- //圆心坐标
- private int mPointX=0, mPointY=0;
- //半径
- private int mRadius = 0;
- //每两个点间隔的角度
- private int mDegreeDelta;
- public RoundSpinView(Context context, int px, int py, int radius) {
- super(context);
- mPaint.setColor(Color.RED);
- mPaint.setStrokeWidth(2);
- setBackgroundResource(R.drawable.menubkground);
- mPointX = px;
- mPointY = py;
- mRadius = radius;
- setupStones();
- computeCoordinates();
- }
- /**
- * 初始化每个点
- */
- private void setupStones() {
- mStones = new BigStone[STONE_COUNT];
- BigStone stone;
- int angle = 0;
- mDegreeDelta = 360/STONE_COUNT;
- for(int index=0; index<STONE_COUNT; index++) {
- stone = new BigStone();
- stone.angle = angle;
- stone.bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.menu1+index);
- angle += mDegreeDelta;
- mStones[index] = stone;
- }
- }
- /**
- * 重新计算每个点的角度
- */
- private void resetStonesAngle(float x, float y) {
- int angle = computeCurrentAngle(x, y);
- Log.d("RoundSpinView", "angle:"+angle);
- for(int index=0; index<STONE_COUNT; index++) {
- mStones[index].angle = angle;
- angle += mDegreeDelta;
- }
- }
- /**
- * 计算每个点的坐标
- */
- private void computeCoordinates() {
- BigStone stone;
- for(int index=0; index<STONE_COUNT; index++) {
- stone = mStones[index];
- stone.x = mPointX+ (float)(mRadius * Math.cos(stone.angle*Math.PI/180));
- stone.y = mPointY+ (float)(mRadius * Math.sin(stone.angle*Math.PI/180));
- }
- }
- /**
- * 计算第一个点的角度
- * @param x
- * @param y
- * @return
- */
- private int computeCurrentAngle(float x, float y) {
- 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;
- }
- Log.d("RoundSpinView", "x:"+x+",y:"+y+",degree:"+degree);
- return degree;
- }
- @Override
- public boolean dispatchTouchEvent(MotionEvent event) {
- resetStonesAngle(event.getX(), event.getY());
- computeCoordinates();
- invalidate();
- return true;
- }
- @Override
- public void onDraw(Canvas canvas) {
- canvas.drawPoint(mPointX, mPointY, mPaint);
- for(int index=0; index<STONE_COUNT; index++) {
- if(!mStones[index].isVisible) continue;
- drawInCenter(canvas, mStones[index].bitmap, mStones[index].x, mStones[index].y);
- //不想有红线,就注掉下面这句
- // canvas.drawLine(mPointX, mPointY, mStones[index].x, mStones[index].y, mPaint);
- }
- }
- /**
- * 把中心点放到中心处
- * @param canvas
- * @param bitmap
- * @param left
- * @param top
- */
- void drawInCenter(Canvas canvas, Bitmap bitmap, float left, float top) {
- canvas.drawPoint(left, top, mPaint);
- canvas.drawBitmap(bitmap, left-bitmap.getWidth()/2, top-bitmap.getHeight()/2, null);
- }
- class BigStone {
- //图片
- Bitmap bitmap;
- //角度
- int angle;
- //x坐标
- float x;
- //y坐标
- float y;
- //是否可见
- boolean isVisible = true;
- }
- }
代码里注释也很清楚。STONE_COUNT表示菜单的数目,可以设置为1到7,更大的数字需要图片支持,我只放了7张图片。
如果触摸的点不在圆周上,会自动计算出点到圆心的直线跟圆的交点,然后映射上去。
5个菜单的效果,画了线的:
6个菜单的效果:
Ok,代码也贡献出来。
点击这里下载代码。
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