Android简单实现圆盘抽奖界面

闲来无事，做了一个简单的抽奖转盘的ui实现，供大家参考

package com.microchange.lucky; 

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View; 

public class HalfCircle extends View { 

 private Paint paint;
 private RectF oval;
 private float startAngle;
 private float sweepSpeed;
 private float sweepAngle;
 boolean useCenter;
 int count;// 等份
 @Override
 protected void onDraw(Canvas canvas) {
  setSweepAngle(count);
  while (startAngle <= 360) {
   if (startAngle % (count*3) == 0) {
    paint.setColor(Color.BLUE);
   } else if (startAngle % (count*2) == 0){
    paint.setColor(Color.GREEN);
   }else {
    paint.setColor(Color.RED);
   }
   Log.e(""+startAngle, paint.getColor()+"");
   canvas.drawArc(oval, startAngle, sweepAngle, useCenter, paint);
   startAngle += count;
  }
  float centerX = oval.centerX();
  float centerY = oval.centerY();
  paint.setColor(Color.WHITE);
//  paint.setStrokeWidth(5);
//  paint.setStyle(Paint.Style.STROKE); //设置空心
  paint.setAntiAlias(true); //消除锯齿
  canvas.drawCircle(centerX, centerY, 50, paint);
  String text = "奖";
  paint.setTextSize(20 * getContext().getResources().getDisplayMetrics().density);
  float measureText = paint.measureText(text);
  float textY = paint.descent() - paint.ascent();
  paint.setColor(Color.RED);
//  canvas.drawLine(0, centerY, 480, centerY, paint);
//  canvas.drawText(text, centerX-(measureText/2), centerY, paint);
  canvas.drawText(text, centerX-(measureText/2), centerY+(textY/4), paint);
 } 

 private void init() {
  paint = new Paint();
  paint.setColor(Color.BLUE);
  paint.setAntiAlias(true);
  paint.setStrokeWidth(5);
 } 

 @Override
 public boolean onTouchEvent(MotionEvent event) {
  return super.onTouchEvent(event);
 } 

 /**
  * @return the count
  */
 public int getCount() {
  return count;
 } 

 /**
  * @param count the count to set
  */
 public void setCount(int count) {
  this.count = 360 / count;
 } 

 public Paint getPaint() {
  return paint;
 } 

 public void setPaint(Paint paint) {
  this.paint = paint;
 } 

 public RectF getOval() {
  return oval;
 } 

 public void setOval(RectF oval) {
  this.oval = oval;
 } 

 public float getStartAngle() {
  return startAngle;
 } 

 public void setStartAngle(float startAngle) {
  this.startAngle = startAngle;
 } 

 public float getSweepSpeed() {
  return sweepSpeed;
 } 

 public void setSweepSpeed(float sweepSpeed) {
  this.sweepSpeed = sweepSpeed;
 } 

 public float getSweepAngle() {
  return sweepAngle;
 } 

 public void setSweepAngle(float sweepAngle) {
  this.sweepAngle = sweepAngle;
 } 

 public boolean isUseCenter() {
  return useCenter;
 } 

 public void setUseCenter(boolean useCenter) {
  this.useCenter = useCenter;
 } 

 public HalfCircle(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  init();
 } 

 public HalfCircle(Context context, AttributeSet attrs) {
  this(context, attrs, 0);
 } 

 public HalfCircle(Context context) {
  this(context, null, 0);
 } 

} 

package com.microchange.lucky; 

import android.app.Activity;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.Animation;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.Interpolator;
import android.view.animation.RotateAnimation; 

public class MainActivity extends Activity {
 RectF rect;
 int radius = 300; 

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  HalfCircle circle = new HalfCircle(getApplicationContext());
  circle.setOval(getRectF());
//  circle.setStartAngle(90);
  circle.setUseCenter(true);
  circle.setCount(9);
  Animation animation = new RotateAnimation(0, 135*10, getRectF().centerX(), getRectF().centerY());
  animation.setDuration(5000);
  animation.setInterpolator(new DecelerateInterpolator());
//  animation.setRepeatCount(-1);
  circle.setAnimation(animation );
//  animation.start();
  setContentView(circle);
 } 

 public RectF getRectF(){
  if (rect==null){
//   getWindow().getDecorView().getWidth()
   int width = getResources().getDisplayMetrics().widthPixels;
   int height = getResources().getDisplayMetrics().heightPixels;
   int top = (height - radius)/2;
   int left = (width - radius)/2;
   rect = new RectF(left, top, left+radius, top+radius);
  }
  return rect;
 }
}

希望本文所述对大家学习Android程序设计有所帮助。