Android实现圆形渐变加载进度条

最近设计要求要一个圆形进度条渐变的需求：

1.画圆形进度条

2.解决渐变

最终实现效果代码

package com.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.SweepGradient;
import android.util.AttributeSet;
import android.view.View;
import com.fx.R;
public class CompletedView extends View {

// 画实心圆的画笔
private Paint mCirclePaint;
// 画圆环的画笔
private Paint mRingPaint;
// 画圆环的画笔背景色
private Paint mRingPaintBg;
// 画字体的画笔
private Paint mTextPaint;
// 圆形颜色
private int mCircleColor;
// 圆环颜色
private int mRingColor;
// 圆环背景颜色
private int mRingBgColor;
// 半径
private float mRadius;
// 圆环半径
private float mRingRadius;
// 圆环宽度
private float mStrokeWidth;
// 圆心x坐标
private int mXCenter;
// 圆心y坐标
private int mYCenter;
// 字的长度
private float mTxtWidth;
// 字的高度
private float mTxtHeight;
// 总进度
private int mTotalProgress = 100;
// 当前进度
private int mProgress;

private String string;

public CompletedView(Context context, AttributeSet attrs) {
 super(context, attrs);
 // 获取自定义的属性
 initAttrs(context, attrs);
 initVariable();
}

//属性
private void initAttrs(Context context, AttributeSet attrs) {
 TypedArray typeArray = context.getTheme().obtainStyledAttributes(attrs,
   R.styleable.TasksCompletedView, 0, 0);
 mRadius = typeArray.getDimension(R.styleable.TasksCompletedView_radius, 80);
 mStrokeWidth = typeArray.getDimension(R.styleable.TasksCompletedView_strokeWidth, 10);
 mCircleColor = typeArray.getColor(R.styleable.TasksCompletedView_circleColor, 0xFFFFFFFF);
 mRingColor = typeArray.getColor(R.styleable.TasksCompletedView_ringColor, 0xFFFFFFFF);
 mRingBgColor = typeArray.getColor(R.styleable.TasksCompletedView_ringBgColor, 0xFFFFFFFF);

mRingRadius = mRadius + mStrokeWidth / 2;
}
RectF oval;
//初始化画笔
private void initVariable() {
 oval = new RectF();
 //内圆
 mCirclePaint = new Paint();
 mCirclePaint.setAntiAlias(true);
 mCirclePaint.setColor(mCircleColor);
 mCirclePaint.setStyle(Paint.Style.FILL);
 mCirclePaint.setStrokeCap(Paint.Cap.ROUND);

//外圆弧背景
 mRingPaintBg = new Paint();
 mRingPaintBg.setAntiAlias(true);
 mRingPaintBg.setColor(mRingBgColor);
 mRingPaintBg.setStyle(Paint.Style.STROKE);
 mRingPaintBg.setStrokeWidth(mStrokeWidth);

//外圆弧
 mRingPaint = new Paint();
 mRingPaint.setAntiAlias(true);
//  mRingPaint.setColor(mRingColor);
 mRingPaint.setStyle(Paint.Style.STROKE);
 mRingPaint.setStrokeWidth(mStrokeWidth);
 mRingPaint.setStrokeCap(Paint.Cap.ROUND);//设置线冒样式，有圆 有方

//中间字
 mTextPaint = new Paint();
 mTextPaint.setAntiAlias(true);
 mTextPaint.setStyle(Paint.Style.FILL);
 mTextPaint.setColor(mRingColor);
 mTextPaint.setTextSize(mRadius / 2);

Paint.FontMetrics fm = mTextPaint.getFontMetrics();
 mTxtHeight = (int) Math.ceil(fm.descent - fm.ascent);
}
SweepGradient sweepGradient;
//画图
@Override
protected void onDraw(Canvas canvas) {
 mXCenter = getWidth() / 2;
 mYCenter = getHeight() / 2;

//内圆
 canvas.drawCircle(mXCenter, mYCenter, mRadius, mCirclePaint);

//外圆弧背景
 RectF oval1 = new RectF();
 oval1.left = (mXCenter - mRingRadius);
 oval1.top = (mYCenter - mRingRadius);
 oval1.right = mRingRadius * 2 + (mXCenter - mRingRadius);
 oval1.bottom = mRingRadius * 2 + (mYCenter - mRingRadius);
 canvas.drawArc(oval1, 0, 360, false, mRingPaintBg); //圆弧所在的椭圆对象、圆弧的起始角度、圆弧的角度、是否显示半径连线

//外圆弧
 if (mProgress > 0 ) {

oval.left = (mXCenter - mRingRadius);
  oval.top = (mYCenter - mRingRadius);
  oval.right = mRingRadius * 2 + (mXCenter - mRingRadius);
  oval.bottom = mRingRadius * 2 + (mYCenter - mRingRadius);
  if (sweepGradient==null) {
   int[] arcColors= new int[]{mRingColor,Color.parseColor("#b05e39"),mRingColor};
   float[] arcPostion=new float[]{0.0f,0.5f,0.95f};
//    sweepGradient = new SweepGradient(mXCenter, mYCenter, mRingColor,Color.parseColor("#b05e39"));
   sweepGradient = new SweepGradient(mXCenter, mYCenter, arcColors,arcPostion);

Matrix matrix = new Matrix();
   matrix.setRotate(-90,mXCenter,mYCenter);
   sweepGradient.setLocalMatrix(matrix);
   mRingPaint.setShader(sweepGradient);
  }
  canvas.drawArc(oval, -90, ((float)mProgress / mTotalProgress) * 360, false, mRingPaint); //

//字体
  String txt = mProgress + "％";
  mTxtWidth = mTextPaint.measureText(txt, 0, txt.length());
  canvas.drawText(txt, mXCenter - mTxtWidth / 2, mYCenter + mTxtHeight / 4, mTextPaint);
 }
}
public void setText(String string){

}

//设置进度
public void setProgress(int progress) {
 mProgress = progress;
 postInvalidate();//重绘
}
}

来源：https://blog.csdn.net/HF1203/article/details/100887321