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;

/**
 * 自定義帶圓點的進度條
 */
public class HalfProgressBar extends View{
 private int maxProgress = 100;
 //設置進度條背景寬度
 private float progressStrokeWidth = 3;
 //設置進度條進度寬度
 private float marxArcStorkeWidth = 6;
 //設置進度條圓點的寬度
 private float circularDotWidth=15;


 /**
  * 畫筆對象的引用
  */
 private Paint paint;

 public synchronized int getProgress() {
  return progress;
 }

 /**
  * Android提供了Invalidate方法實現界面刷新，但是Invalidate不能直接在線程中調用，因為他是違背了單線程模型：Android UI操作并不是線程安全的，并且這些操作必須在UI線程中調用。
  * 而postInvalidate()在工作者線程中被調用 使用postInvalidate則比較簡單，不需要handler，直接在線程中調用postInvalidate即可。 
  * @param progress 傳過來的進度
  */
 public void setProgress(int progress) {
  if (progress < 0) {
   progress = 0;
  }
  if (progress > maxProgress) {
   progress = maxProgress;
  }
  if (progress <= maxProgress) {
   this.progress = progress;
   postInvalidate();
  }
 }
 /**
  * 當前進度
  */
 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();
  //這是自定義view 必須要寫的
  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 自動生成的方法存根
  super.onDraw(canvas);
  float width = getWidth();
  float height = getHeight();
  paint.setAntiAlias(false); // 設置畫筆為抗鋸齒
  paint.setColor(roundColor); // 設置畫筆顏色

  paint.setStrokeWidth(progressStrokeWidth); // 線寬
  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);//半徑


  //調整圓背景的大小
  canvas.drawArc(oval, 180, 180, false, paint); // 繪制紅絲圓圈，即進度條背景
  //進度條顏色
  paint.setColor(roundProgressColor);
  paint.setStrokeWidth(marxArcStorkeWidth);
  canvas.drawArc(oval, 180, 180 * ((float) progress / (float) maxProgress), false, paint); // 繪制進度圓弧，這里是藍色


  //畫圓點
  paint.setColor(circularDotColor);
  paint.setAntiAlias(true); // 設置畫筆為抗鋸齒
  paint.setStyle(Paint.Style.FILL);
  paint.setStrokeWidth(circularDotWidth);
  //當畫筆樣式為STROKE或FILL_OR_STROKE時，設置筆刷的圖形樣式，如圓形樣式Cap.ROUND,或方形樣式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);

 }

}

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <!--自定義半圓形加載進度條-->
 <declare-styleable name="HalfProgressBar">
  <attr name="roundColor1" format="color"/>
  <attr name="roundProgressColor1" format="color"/>
  <attr name="circularDotColor1" format="color"/>
 </declare-styleable>
</resources>

<com.jyc99.demo.HalfProgressBar
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:id="@+id/view"
  android:layout_centerHorizontal="true"
  android:layout_marginTop="42dp"
  android_custom:roundColor1="#fc422b"
  android_custom:roundProgressColor1="#fa432e"
  android_custom:circularDotColor1="#246223"/>