Android自定义带圆点的半圆形进度条

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;

/**
 * 自定义带圆点的进度条
 */
public class HalfProgressBar extends View{
 private int maxProgress = 100;
 //设置进度条背景宽度
 private float progressStrokeWidth = 3;
 //设置进度条进度宽度
 private float marxArcStorkeWidth = 6;
 //设置进度条圆点的宽度
 private float circularDotWidth=15;


 /**
  * 画笔对象的引用
  */
 private Paint paint;

 public synchronized int getProgress() {
  return progress;
 }

 /**
  * Android提供了Invalidate方法实现界面刷新，但是Invalidate不能直接在线程中调用，因为他是违背了单线程模型：Android UI操作并不是线程安全的，并且这些操作必须在UI线程中调用。
  * 而postInvalidate()在工作者线程中被调用 使用postInvalidate则比较简单，不需要handler，直接在线程中调用postInvalidate即可。 
  * @param progress 传过来的进度
  */
 public void setProgress(int progress) {
  if (progress < 0) {
   progress = 0;
  }
  if (progress > maxProgress) {
   progress = maxProgress;
  }
  if (progress <= maxProgress) {
   this.progress = progress;
   postInvalidate();
  }
 }
 /**
  * 当前进度
  */
 private int progress = 99;

 private RectF oval;
 private int roundProgressColor;
 private int roundColor;
 private int circularDotColor;
 public HalfProgressBar(Context context) {
  super(context);
 }

 public HalfProgressBar(Context context, AttributeSet attrs) {
  super(context, attrs);
  paint = new Paint();
  oval = new RectF();
  //这是自定义view 必须要写的
  TypedArray mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.HalfProgressBar);
  roundProgressColor = mTypedArray.getColor(R.styleable.HalfProgressBar_roundProgressColor1, Color.YELLOW);
  roundColor=mTypedArray.getColor(R.styleable.HalfProgressBar_roundColor1, Color.YELLOW);
  circularDotColor=mTypedArray.getColor(R.styleable.HalfProgressBar_circularDotColor1, Color.YELLOW);

 }

 public HalfProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  paint = new Paint();
  oval = new RectF();
  TypedArray mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.HalfProgressBar);
  roundProgressColor = mTypedArray.getColor(R.styleable.HalfProgressBar_roundProgressColor1, Color.YELLOW);
  roundColor=mTypedArray.getColor(R.styleable.HalfProgressBar_roundColor1, Color.YELLOW);

 }

 @Override
 protected void onDraw(Canvas canvas) {
  // TODO 自动生成的方法存根
  super.onDraw(canvas);
  float width = getWidth();
  float height = getHeight();
  paint.setAntiAlias(false); // 设置画笔为抗锯齿
  paint.setColor(roundColor); // 设置画笔颜色

  paint.setStrokeWidth(progressStrokeWidth); // 线宽
  paint.setStyle(Paint.Style.STROKE);

  oval.left = marxArcStorkeWidth / 2; // 左上角x
  oval.top = circularDotWidth; // 左上角y
  oval.right = width - circularDotWidth / 2; // 左下角x
  oval.bottom = width - circularDotWidth / 2; // 右下角y
  float bangjing = ((width - circularDotWidth/2) / 2);//半径


  //调整圆背景的大小
  canvas.drawArc(oval, 180, 180, false, paint); // 绘制红丝圆圈，即进度条背景
  //进度条颜色
  paint.setColor(roundProgressColor);
  paint.setStrokeWidth(marxArcStorkeWidth);
  canvas.drawArc(oval, 180, 180 * ((float) progress / (float) maxProgress), false, paint); // 绘制进度圆弧，这里是蓝色


  //画圆点
  paint.setColor(circularDotColor);
  paint.setAntiAlias(true); // 设置画笔为抗锯齿
  paint.setStyle(Paint.Style.FILL);
  paint.setStrokeWidth(circularDotWidth);
  //当画笔样式为STROKE或FILL_OR_STROKE时，设置笔刷的图形样式，如圆形样式Cap.ROUND,或方形样式Cap.SQUARE
  paint.setStrokeCap(Paint.Cap.ROUND);
  float jindu = ((float) progress * 1.8f);
  canvas.drawPoint(bangjing - ((float) (Math.sin((Math.PI / (double) 180) * (jindu <= 90 ? 90 - (jindu) : -jindu + 90))) * bangjing),
   bangjing+circularDotWidth - ((float) (Math.cos((Math.PI / (double) 180) * (double) (jindu <= 90 ? 90 - jindu : -jindu + 90))) * bangjing), paint);

 }

}

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