Android开发 View_自定义圆环进度条View

前言

　　一个实现，空心圆环的自定义View，已经封装完好，可以直接使用。

效果图

代码

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.view.View;

import androidx.annotation.ColorInt;

import androidx.annotation.Nullable;

public class RingProgressBar extends View {

    private Paint mPaint;

    private int mBgRingColor = Color.BLACK;

    private int mProgressRingColor = Color.RED;

    private int mBgRingWidth = 20;

    private int mProgressRingWidth = 20;

    private int mMax = 100;

    private int mCurrentProgress = 0;

    private int width = 0;

    private int height = 0;

    public RingProgressBar(Context context) {

        super(context);

    }

    public RingProgressBar(Context context, @Nullable AttributeSet attrs) {

        super(context, attrs);

        mPaint = new Paint();

    }

    public RingProgressBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {

        super(context, attrs, defStyleAttr);

        mPaint = new Paint();

    }

    public RingProgressBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {

        super(context, attrs, defStyleAttr, defStyleRes);

        mPaint = new Paint();

    }

    @Override

    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);

        drawBgRing(canvas);

        drawProgressRing(canvas);

    }

    /**

     * 测量尺寸

     */

    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        width = MeasureSpec.getSize(widthMeasureSpec);

        height = MeasureSpec.getSize(heightMeasureSpec);

        setMeasuredDimension(width, height);

    }

    public void setBgRing(@ColorInt int bgRingColor, int ringWidth) {

        mBgRingColor = bgRingColor;

        mBgRingWidth = dip2px(ringWidth);

        postInvalidate();

    }

    public void setProgressRing(@ColorInt int progressRingColor, int ringWidth) {

        mProgressRingColor = progressRingColor;

        mProgressRingWidth = dip2px(ringWidth);

        postInvalidate();

    }

    /**

     * 设置最大值

     *

     * @param max

     */

    public void setMax(int max) {

        mMax = max;

        postInvalidate();

    }

    /**

     * 设置进度

     *

     * @param progress

     */

    public void setProgress(int progress) {

        mCurrentProgress = progress;

        postInvalidate();   //请求失效,重新绘制

    }

    /**

     * 绘制背景环

     * @param canvas

     */

    private void drawBgRing(Canvas canvas) {

        mPaint.setColor(mBgRingColor);      //设置画笔颜色

        mPaint.setStyle(Paint.Style.STROKE);//设置画笔为描边

        mPaint.setStrokeWidth(mBgRingWidth);//设置描边宽度

        mPaint.setStrokeCap(Paint.Cap.BUTT);//设置画笔收笔类型

        mPaint.setAntiAlias(true);          //抗锯齿

        canvas.drawCircle(width / 2, height / 2, (width - mBgRingWidth) / 2, mPaint);   //画圆形

        mPaint.reset();

    }

    /**

     * 绘制进度环

     * @param canvas

     */

    private void drawProgressRing(Canvas canvas) {

        mPaint.setStyle(Paint.Style.STROKE);

        mPaint.setStrokeCap(Paint.Cap.BUTT);

        mPaint.setColor(mProgressRingColor);

        mPaint.setStrokeWidth(mProgressRingWidth);

        mPaint.setAntiAlias(true);

        RectF rectF = new RectF();

        rectF.left = 0 + mProgressRingWidth / 2;

        rectF.right = width - mProgressRingWidth / 2;

        rectF.top = 0 + mProgressRingWidth / 2;

        rectF.bottom = height - mProgressRingWidth / 2;

        float progress = 0;

        if (mCurrentProgress < mMax) {

            float proportion = (float) 360 / (float) mMax;

            progress = mCurrentProgress * proportion;

        } else {

            progress = 360;

        }

        canvas.drawArc(rectF, 270, progress, false, mPaint);    //画圆弧

        mPaint.reset();

    }

    /**

     * 根据手机分辨率从DP转成PX

     * @param dpValue

     * @return

     */

    public int dip2px(float dpValue) {

        float scale = getResources().getDisplayMetrics().density;

        return (int) (dpValue * scale + 0.5f);

    }

}