Android 自定义View 实现表盘效果

看一哥们做了这个效果，我也来凑下热闹

我的实现：

package com.stone.clock.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.os.Build;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.support.annotation.RequiresApi;
import android.util.AttributeSet;
import android.view.View;

import java.util.Calendar;
import java.util.TimeZone;

/**
 * 时钟
 * author : stone
 * email  : [e-mail]
 * time   : 2016/11/7 17 46
 */

public class ClockView extends View {
    private static final int H_POINTER_WIDTH = 15; //时针宽
    private static final int M_POINTER_WIDTH = 10; //分针宽
    private static final int S_POINTER_WIDTH = 5; //秒针宽
    private static final int SCALE_LINE_LENGTH = 50; //刻度线长
    private static final int SCALE_LINE_WIDTH = 6; //刻度线宽
    private static final int M_S_DEGREES_UNIT = 360 / 60; //分、秒针每个数字走的角度
    private static final int H_DEGREES_UNIT = 360 / 12; //时针每个数字走的角度
    private Paint mPaint;
    private int mW, mH, mCx, mCy, mR;
    private int mCount;

    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            postInvalidate();
        }
    };

    public ClockView(Context context) {
        this(context, null);
    }

    public ClockView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public ClockView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    public ClockView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        init();
    }

    private void init() {
        mPaint = new Paint();

    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mW = getWidth();
        mH = getHeight();

        mR = Math.min(mW, mH) / 2 - 20;
        mCx = mW / 2;
        mCy = mH / 2;

    }

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

        long beginTime = SystemClock.uptimeMillis();

        mPaint.setColor(Color.WHITE);
        canvas.drawCircle(mCx, mCy, mR, mPaint); //外圆
        mPaint.setColor(Color.BLACK);
        canvas.drawCircle(mCx, mCy, mR / 12, mPaint); //圆心

        /*
        绘制刻度
         */
        for (int i = 0; i < 60; i++) {
            canvas.save();
            canvas.rotate(M_S_DEGREES_UNIT * i, mCx, mCy);
            mPaint.setStrokeWidth(SCALE_LINE_WIDTH);
            canvas.drawLine(mCx, mCy - mR, mCx, mCy - mR + SCALE_LINE_LENGTH, mPaint);
            if (i % 5 == 0) {
                mPaint.setStrokeWidth(SCALE_LINE_WIDTH + 5);
                canvas.drawLine(mCx, mCy - mR, mCx, mCy - mR + SCALE_LINE_LENGTH + 10, mPaint);

                String num = i == 0 ? 12 + "" : i / 5 + "";
                float x = mCx - mPaint.measureText(num) / 2;
                float y = mCy - mR + SCALE_LINE_LENGTH + 30;
                mPaint.setTextSize(50);
                canvas.drawText(num, x, y + Math.abs(mPaint.ascent()), mPaint);
            }
            canvas.restore();

        }

        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT+8"));
        int hour = calendar.get(Calendar.HOUR);
        int minute = calendar.get(Calendar.MINUTE);
        int second = calendar.get(Calendar.SECOND);

        /*
        分针在最下面 最先绘制
         */
        canvas.save();
        float mDegrees = minute * M_S_DEGREES_UNIT;
        canvas.rotate(mDegrees, mCx, mCy);
        mPaint.setColor(Color.GREEN);
        Path p = new Path();
        p.addRect(new RectF(mCx - M_POINTER_WIDTH, mCy - mR/4*3, mCx + M_POINTER_WIDTH, mCy + mR/5), Path.Direction.CW);
        p.quadTo(mCx, mCy - mR/4*3 - 40, mCx + M_POINTER_WIDTH, mCy - mR/4*3);
        canvas.drawPath(p, mPaint);
        canvas.restore();

        /*
        时针在中间
            分针60分走360度; 时针1小时(即60分)走30度
            mDegrees:hDegrees = 360:30 = 12:1
            hDegrees = mDegrees / 12; 时针相对于分钟数所要走的角度
         */
        canvas.save();
        canvas.rotate(mDegrees / 12 + hour * H_DEGREES_UNIT, mCx, mCy);
        mPaint.setColor(Color.RED);
        p = new Path();
        p.addRect(new RectF(mCx - H_POINTER_WIDTH, mCy - mR/3*2, mCx + H_POINTER_WIDTH, mCy + mR/5), Path.Direction.CW);
        p.quadTo(mCx, mCy - mR/3*2 - 30, mCx + H_POINTER_WIDTH, mCy - mR/3*2);
        canvas.drawPath(p, mPaint);
        canvas.restore();

        /*
        秒针在最上面
         */
        canvas.save();
        canvas.rotate(second * M_S_DEGREES_UNIT, mCx, mCy);
        mPaint.setColor(Color.BLACK);
        p = new Path();
        p.addRect(new RectF(mCx - S_POINTER_WIDTH, mCy - mR/5*4, mCx + S_POINTER_WIDTH, mCy + mR/5), Path.Direction.CW);
        p.quadTo(mCx, mCy - mR/5*4 - 30, mCx + S_POINTER_WIDTH, mCy - mR/5*4);
        canvas.drawPath(p, mPaint);
        canvas.restore();

        long spanTime = SystemClock.uptimeMillis() - beginTime;
//        System.out.println("间隔时间" + spanTime);
        if (mCount < 5) {//12的位置开始绘制时位置不对，刷新一次后就正常，这里让其快速刷新几次
            mHandler.sendEmptyMessage(0);
            mCount++;
        } else
            mHandler.sendEmptyMessageDelayed(0, 1000 - spanTime);
    }

}

那哥们的时针角度计算是：hour*unit+minute/2;   我这里按比例算的  :)

链接下他的博文：android 自定义view实现表盘效果   里面有较具体的说明

我的自定义View项目地址： https://github.com/aa86799/MyCustomView (欢迎start&fork)

本文地址：https://github.com/aa86799/MyCustomView/tree/master/clock