Android实现抽奖转盘实例代码

本文详述了android抽奖程序的实现方法，程序为一个抽奖大转盘代码，里面定义了很多图形方法和动画。

实现主要功能的SlyderView.java源代码如下：

import android.app.Activity;
import android.content.Context;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.EmbossMaskFilter;
import android.graphics.MaskFilter;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Paint.Style;
import android.graphics.PorterDuff.Mode;
import android.graphics.Path;
import android.graphics.RadialGradient;
import android.graphics.RectF;
import android.graphics.Shader.TileMode;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
public class SlyderView extends View{
 public SlyderView(Context context, AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
   init(context);
 }
 public SlyderView(Context context, AttributeSet attrs) {
   super(context, attrs);
   init(context);
 }
 public SlyderView(Context context) {
   super(context);
   init(context);
 }
 /**
  * 屏幕宽度
  */
 private int screenW;
 /**
  * 屏幕的高度
  */
 private int screenH;
 /**
  * 分割的度数
  */
 private int [] drgrees = {20,50,40,90,70,40,50};
 /***
  * 分割的文字
  */
 private String [] strs = {"level1","level2","level3","level4","level5","level6","level7"};
 /**
  * 分割的颜色
  */
 private int [] colos = new int[] { 0xfed9c960, 0xfe57c8c8, 0xfe9fe558, 0xfef6b000, 0xfef46212, 0xfecf2911, 0xfe9d3011 };
 /**
  * 画笔
  */
 private Paint paint;
 /**
  * 文字的大小
  */
 private float textSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 15, getResources().getDisplayMetrics());
 /**
  * 文字的颜色
  */
 private int textcolor = Color.WHITE;
 /**
  * 园的半径
  */
 private float radius = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 100, getResources().getDisplayMetrics());
 /**
  * 画文字的距离
  */
 private float textdis = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 80, getResources().getDisplayMetrics());
 /**
  * 画箭头的大小
  */
 private float roketSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 10, getResources().getDisplayMetrics());

private float initDegress = 0;
 /**
  * 圆心
  */
 private float centerX;
 /**
  * 圆心
  */
 private float centerY;
 /**
  * 立体边缘
  */
 private MaskFilter filter = new EmbossMaskFilter(new float[] { 1, 1, 1 },0.4f, 6, 3.5f);
 private MaskFilter outerFilter = new BlurMaskFilter(10, BlurMaskFilter.Blur.OUTER);
 private MaskFilter innerFilter = new BlurMaskFilter(10, BlurMaskFilter.Blur.INNER);
 @SuppressWarnings("deprecation")
 private void init(Context context){
   paint = new Paint();
   paint.setAntiAlias(true);
   paint.setStyle(Style.FILL);
   paint.setColor(Color.WHITE);
   screenW = ((Activity)context).getWindowManager().getDefaultDisplay().getWidth();
   screenH = ((Activity)context).getWindowManager().getDefaultDisplay().getHeight();
   int[] colores = new int[3];
   colores[0] = Color.rgb(0xfF, 0x99, 0x00);
   colores[1] = Color.rgb(0xff, 0xff, 0x00);
   colores[2] = Color.rgb(0xff, 0x99, 0x00);
   float[] positions = new float[3];
   positions[0] = 0.0f;
   positions[1] = 0.5f;
   positions[2] = 1.0f;
   gradient = new RadialGradient(centerX, centerY, radius/5, colores, positions, TileMode.CLAMP);
 }
 /**
  * 绘制三角箭头
  */
 private Path path = new Path();
 /**
  * 绘制矩形框
  */
 private RectF oval;
 /**
  * 外圆内阴影矩阵
  */
 private ColorMatrixColorFilter colorFilter = new ColorMatrixColorFilter(new float[]{
     1,0,0,0,0,
     0,1,0,0,0,
     0,0,1,0,0,
     0,0,0,-1,255
 });
 @Override
 protected void onDraw(Canvas canvas) {
   super.onDraw(canvas);
   centerX = screenW/2;
   centerY = screenH/2;
   oval = new RectF(centerX-radius,centerY-radius,centerX+radius,centerY+radius);
   float start = 0;
   paint.setColor(Color.rgb(0xdd, 0xdd, 0xdd));
   paint.setAlpha(127);
   canvas.drawCircle(centerX, centerY, radius+10, paint);
   paint.setAlpha(255);
   //画扇形
   paint.setAntiAlias(true);
   for(int i=0;i<drgrees.length;i++){
     float sweepAngle = drgrees[i];
     float startAngle = start;
     paint.setColor(colos[i％colos.length]);
     canvas.drawArc(oval, startAngle, sweepAngle, true, paint);
     start += drgrees[i];
   }
   //画文字
   paint.setColor(textcolor);
   paint.setAntiAlias(true);
   paint.setTextSize(textSize);
   paint.setTextAlign(Paint.Align.RIGHT);
   start = 0;
   for(int i=0;i<drgrees.length;i++){
     canvas.save();
     canvas.rotate(start+drgrees[i]/2, centerX, centerY);
     canvas.drawText(strs[i], centerX+textdis, centerY, paint);
     canvas.restore();
     start += drgrees[i];
   }
   int saveCount = canvas.save();
   //画外层立体效果
   paint.setColorFilter(colorFilter);
   canvas.saveLayer(oval,paint,Canvas.ALL_SAVE_FLAG);
   paint.setColorFilter(null);
   canvas.drawARGB(255, 0, 0, 0);
   paint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
   canvas.drawCircle(centerX, centerY, radius, paint);
   paint.setXfermode(null);
   paint.setMaskFilter(innerFilter);
   paint.setColor(Color.argb(0xff, 0, 0, 0));
   canvas.drawCircle(centerX, centerY, radius, paint);
   paint.setMaskFilter(null);
   canvas.restoreToCount(saveCount);
   //画内圆和内园效果
   canvas.save();
   paint.setColor(Color.argb(0xff, 0, 0, 0));
   paint.setAntiAlias(true);
   paint.setMaskFilter(outerFilter);
   canvas.rotate(initDegress, centerX, centerY);
   canvas.drawCircle(centerX, centerY, radius/3, paint);
   paint.setMaskFilter(null);
   paint.setColor(Color.WHITE);
   canvas.drawCircle(centerX, centerY, radius/3, paint);
   //画三角型叠加当箭头
   path.moveTo(centerX-radius/3, centerY);
   path.lineTo(centerX, centerY-radius/3-roketSize);
   path.lineTo(centerX+radius/3, centerY);
   path.close();
   canvas.drawPath(path, paint);
   canvas.restore();
   paint.setMaskFilter(filter);
   paint.setColor(Color.GREEN);
   paint.setShader(gradient);
   canvas.drawCircle(centerX, centerY, radius/5, paint);
   paint.setMaskFilter(null);
   paint.setShader(null);
   //重绘调整三角的指向达到滚动的效果，现实项目中可不能这样用的，效率太低下了，拆分View用动画完成滚动才是王道
   if(isRunning){
     if(initDegress>=360){
       initDegress = 0;
     }
     initDegress +=4;
     invalidate();
   }
   if(isStoping){
     if(initDegress<=360){
       initDegress+=4;
       invalidate();
     }else{
       if(initDegress-360<stop_degress){
         initDegress+=2;
         invalidate();
       }
     }
   }
 }
 private boolean isRunning = false;
 private boolean isStoping = false;
 private int stop_degress =90;
 /**
  * 渐变
  */
 private RadialGradient gradient;
 public void play(){
   isRunning = true;
   invalidate();
 }
 public void stop(int count){
   for(int i =0;i<=count;i++){
     if(i == count){
       stop_degress +=drgrees[i]/2;
     }else{
       stop_degress +=drgrees[i];
     }
   }
   isStoping = true;
   isRunning = false;
   invalidate();
 }
}