1.继承ImageView，重写onDraw()方法
【android|Android带圆形进度条的ImageView】2.在控件的中间位置画圆圈进度和进度文字
3.暴露设置进度值的方法，重绘
public class ProgressImageView extends AppCompatImageView {
private int progress = 0;
//加载的进度
private int diameter = 100;
//圆形进度条的直径
private Paint mPaint;
public ProgressImageView(Context context) {
super(context);
init();
}public ProgressImageView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}public ProgressImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}private void init() {
mPaint = new Paint();
}@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (progress > 0 && progress < 360) {//如果图片加载完成，进度条不显示
/**
* 画进度圆圈，圆圈位置放在图片中间
*/
mPaint.setAntiAlias(true);
//取消锯齿
mPaint.setStrokeWidth(10);
//画笔宽度
mPaint.setColor(Color.BLUE);
//圆圈设置成蓝色
mPaint.setStyle(Paint.Style.STROKE);
//空心
int ho = (getMeasuredWidth() - diameter) / 2;
//水平
int ve = (getMeasuredHeight() - diameter) / 2;
//垂直
RectF rectF = new RectF();
rectF.left = ho;
rectF.top = ve;
rectF.right = ho + diameter;
rectF.bottom = ve + diameter;
canvas.drawArc(rectF, -90, progress, false, mPaint);
/**
* 画进度文字显示，位置在图片中间向左编译30px，向下移动10px
*/
mPaint.setColor(Color.RED);
//文字设置成红色
mPaint.setStrokeWidth(1);
//画笔宽度
mPaint.setTextSize(25);
//字体大小
canvas.drawText(String.valueOf((int) (progress / 3.6)) + "%", getMeasuredWidth() / 2 - 30, getMeasuredHeight() / 2 + 10, mPaint);
}
}/**
* 设置进度
*
* @param total总的长度
* @param progress 已加载的进度
*/
public void setProgress(int total, int progress) {
this.progress = progress * 360 / total;
postInvalidate();
}
}
