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();
  }
}