package com.xxx.widget;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.ColorInt;
import androidx.annotation.Nullable;

public class DiskView extends View {

    private static final int DEFAULT_THICK = 10;
    private static final int DEFAULT_INNER_COLOR = Color.parseColor("#A0AAAA00");
    private static final int DEFAULT_BORDER_COLOR = Color.parseColor("#333333");

    private Paint mPaint;
    private Path mPath;
    private float mDiskUsedPercent = 0.0f;
    private int mThick = DEFAULT_THICK;
    private int mInnerColor = DEFAULT_INNER_COLOR;
    private int mBorderColor = DEFAULT_BORDER_COLOR;

    public DiskView(Context context) {
        super(context);
        init();
    }

    public DiskView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public DiskView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public void setThick(int thick) {
        if (thick > 0) {
            mThick = thick;
            invalidate();
        }
    }

    public void setInnerColor(@ColorInt int color) {
        mInnerColor = color;
        invalidate();
    }

    public void setBorderColor(@ColorInt int color) {
        mBorderColor = color;
        invalidate();
    }

    public void setDiskUsedPercent(float percent) {
        if (percent >= 0f && percent <= 1f) {
            mDiskUsedPercent = percent;
            invalidate();
        }
    }

    private void init() {
        mPath = new Path();

        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(1f);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        float paintWidth = mPaint.getStrokeWidth();
        float halfPaintWidth = paintWidth / 2;

        float width = getMeasuredWidth() - paintWidth;
        float height = getMeasuredHeight() - paintWidth;

        // 绘制上圆和下圆轮廓
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setColor(mBorderColor);
        canvas.drawOval(halfPaintWidth, halfPaintWidth, width, height - mThick, mPaint);
        mPath.reset();
        mPath.moveTo(width, (height - mThick) / 2f);
        mPath.lineTo(width, (height + mThick) / 2f);
        mPath.arcTo(halfPaintWidth, mThick, width, height, 0, 180, false);
        mPath.lineTo(halfPaintWidth, (height - mThick) / 2f);
        canvas.drawPath(mPath, mPaint);

        // 绘制上圆填充
        mPaint.setColor(mInnerColor);
        mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
        canvas.drawArc(halfPaintWidth, halfPaintWidth, width, height - mThick, -90, mDiskUsedPercent * 360, true, mPaint);

        // 绘制上圆与下圆之间的柱状填充
        float swipeAngle = 0f;
        if (mDiskUsedPercent > 0.75f) {
            swipeAngle = 180;
        } else if (mDiskUsedPercent > 0.25f) {
            swipeAngle = mDiskUsedPercent * 360 - 90;
        }
        if (swipeAngle > 0f) {
            mPath.reset();
            mPath.moveTo(width, (height - mThick) / 2f);
            mPath.lineTo(width, (height + mThick) / 2f);
            // forceMoveTo 设置为 true 会重置起点
            mPath.arcTo(halfPaintWidth, mThick, width, height, 0, swipeAngle, false);
            // sweepAngle 为负表示逆时针方向
            mPath.arcTo(halfPaintWidth, halfPaintWidth, width, height - mThick, swipeAngle, -swipeAngle, false);
            canvas.drawPath(mPath, mPaint);
        }
    }

}

示例.png