Android新手入门实例之Android漂亮时钟的源代码

package com.smart.impl;

import java.util.Calendar;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.View;

public class HandClock  extends View implements Runnable
{
    private int clockImageResourceId;
    private Bitmap bitmap;
    private float scale;
    private float handCenterWidthScale;
    private float handCenterHeightScale;
    private int minuteHandSize;
    private int hourHandSize;
    private Handler handler = new Handler();

    @Override
    public void run()
    {
        // 重新绘制View
        invalidate();
        // 重新设置定时器，在60秒后调用run方法
        handler.postDelayed(this, 60 * 1000);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        // 根据图像的实际大小等比例设置View的大小
        setMeasuredDimension((int) (bitmap.getWidth() * scale), (int) (bitmap
                .getHeight() * scale));
    }

    @Override
    protected void onDraw(Canvas canvas)
    {
        super.onDraw(canvas);
        Paint paint = new Paint();
        Rect src = new Rect();
        Rect target = new Rect();
        src.left = 0;
        src.top = 0;
        src.right = bitmap.getWidth();
        src.bottom = bitmap.getHeight();

        target.left = 0;
        target.top = 0;
        target.bottom = (int) (src.bottom * scale);
        target.right = (int) (src.right * scale);
        // 画表盘图像
        canvas.drawBitmap(bitmap, src, target, paint);
        // 计算表盘中心点的横纵坐标
        float centerX = bitmap.getWidth() * scale * handCenterWidthScale;
        float centerY = bitmap.getHeight() * scale * handCenterHeightScale;
        // 表表盘中心点画一个半径为5的实心圆圈
        canvas.drawCircle(centerX, centerY, 5, paint);
        // 设置分针为3个象素粗
        paint.setStrokeWidth(3);
        Calendar calendar = Calendar.getInstance();
        int currentMinute = calendar.get(Calendar.MINUTE);
        int currentHour = calendar.get(Calendar.HOUR);
        // 计算分针和时间的角度
        double minuteRadian = Math
                .toRadians((360 - ((currentMinute * 6) - 90)) % 360);
        double hourRadian = Math.toRadians((360 - ((currentHour * 30) - 90))
                % 360 - (30 * currentMinute / 60));
        // 在表盘上画分针
        canvas.drawLine(centerX, centerY, (int) (centerX + minuteHandSize
                * Math.cos(minuteRadian)), (int) (centerY - minuteHandSize
                * Math.sin(minuteRadian)), paint);
        // 设置实针为4个象素粗
        paint.setStrokeWidth(4);
        // 在表盘上画分针
        canvas.drawLine(centerX, centerY, (int) (centerX + hourHandSize
                * Math.cos(hourRadian)), (int) (centerY - hourHandSize
                * Math.sin(hourRadian)), paint);
    }

    public HandClock(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        // 读取相应的属性值
        clockImageResourceId = attrs.getAttributeResourceValue(null,
                "clockImageSrc", 0);
        if (clockImageResourceId > 0)
            bitmap = BitmapFactory.decodeResource(getResources(),
                    clockImageResourceId);
        scale = attrs.getAttributeFloatValue(null, "scale", 1);
        handCenterWidthScale = attrs.getAttributeFloatValue(null,
                "handCenterWidthScale", bitmap.getWidth() / 2);
        handCenterHeightScale = attrs.getAttributeFloatValue(null,
                "handCenterHeightScale", bitmap.getHeight() / 2);
        //  在读取分针和时针长度后，将其值按图像的缩放比例进行缩放
        minuteHandSize = (int) (attrs.getAttributeIntValue(null,
                "minuteHandSize", 0) * scale);
        hourHandSize = (int) (attrs.getAttributeIntValue(null, "hourHandSize",
                0) * scale);
        int currentSecond = Calendar.getInstance().get(Calendar.SECOND);
        //  将定时器设在0分时执行run方法
        handler.postDelayed(this, (60 - currentSecond) * 1000);
    }

    @Override
    protected void onDetachedFromWindow()
    {
        super.onDetachedFromWindow();
        //  删除回调类
        handler.removeCallbacks(this);
    }}