Android自定义View实现圆环进度条

本文实例为大家分享了Android自定义View实现圆环进度条的具体代码，供大家参考，具体内容如下

效果展示

动画效果

View实现

1.底层圆环是灰色背景
2.上层圆环是红色背景
3.使用动画画一条弧线

View

/**
* 圆环进度条
*/
public class RoundProgressBar extends View {
//绘制矩形区域
private RectF rectF;
//起始角度
private float startAngle;
//扫过角度
private float sweepAngle;
//画笔
private Paint paint;
//默认控件大小
private int defoutSize;
//默认线条宽度
private int defoutLine;
private int strokeWidth;

private PointF pointF = new PointF();

public RoundProgressBar(Context context) {
 super(context);
 initData();
}

public RoundProgressBar(Context context, AttributeSet attrs) {
 super(context, attrs);
 initData();
}

/**
 * 参数初始化
 */
private void initData() {
 startAngle = 0;
 sweepAngle = 0;
 defoutSize = 400;
 defoutLine = 20;
 strokeWidth = 20;

rectF = new RectF();

//抗锯齿画笔
 paint = new Paint(Paint.ANTI_ALIAS_FLAG);
 paint.setColor(Color.GRAY);
 paint.setStrokeWidth(defoutLine);
 //笔帽样式
 paint.setStrokeCap(Paint.Cap.ROUND);
 paint.setStyle(Paint.Style.STROKE);
}

/**
 * xml -----> 提供可绘制位置
 *
 * @param widthMeasureSpec 宽
 * @param heightMeasureSpec 高
 */
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 setMeasuredDimension(defoutSize, defoutSize);
}

/**
 * 当大小时改变回调
 *
 * @param w
 * @param h
 * @param oldw
 * @param oldh
 */
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
 super.onSizeChanged(w, h, oldw, oldh);

pointF.x = w >> 1;
 pointF.y = h >> 1;

rectF.top = strokeWidth >> 1;
 rectF.bottom = h - (strokeWidth >> 1);
 rectF.left = strokeWidth >> 1;
 rectF.right = w - (strokeWidth >> 1);

}

/**
 * 绘制
 *
 * @param canvas
 */
@Override
protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);

//画布旋转
 paint.setColor(Color.GRAY);
 canvas.rotate(135, pointF.x, pointF.y);
 //绘制圆环
 canvas.drawArc(rectF, startAngle, 270, false, paint);

paint.setColor(Color.RED);
 canvas.drawArc(rectF, startAngle, sweepAngle, false, paint);

}

public void setProgress(float index) {
//防止数值越界
 if (index > 1 || index < 0) {
  return;
 }
 ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, index);
 valueAnimator.setDuration(3000);
 valueAnimator.setInterpolator(new DecelerateInterpolator());
 valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
  @Override
  public void onAnimationUpdate(ValueAnimator animation) {
   sweepAngle = (float) animation.getAnimatedValue() * 270;
   //重写绘制
   invalidate();
  }
 });
 valueAnimator.start();

}
}

最后在Activity中使用setProgress方法赋值进度条的进度来实现效果

progressView.setProgress(0.8f);

来源：https://blog.csdn.net/weixin_45697390/article/details/106364039