waitcanvas.java

基于j2me的电话本基于j2me的电话本

package com.hziee.phone_book.ui;

import java.util.*;
import javax.microedition.lcdui.*;

public class WaitCanvas extends Canvas
{
	/**该类用以个圆弧来表示工作进度*/
    private int mCount, mMaximum;
    private int mInterval;

    private int mWidth, mHeight, mX, mY, mRadius;
    private String mMessage;
    private boolean run = false;

    public WaitCanvas(String message, boolean run)
    {
        this.mMessage = message;
        mCount = 0;
        mMaximum = 36;
        mInterval = 100;

        mWidth = getWidth();
        mHeight = getHeight();

        // Calculate the radius.计算半径
        int halfWidth = (mWidth - mRadius) / 2;
        int halfHeight = (mHeight - mRadius) / 2;
        mRadius = Math.min(halfWidth, halfHeight);

        //	  Calculate the location.
        mX = halfWidth - mRadius / 2;
        mY = halfHeight - mRadius / 2;

        //	  Create a Timer to update the display.
        if (run)
        {
            TimerTask task = new TimerTask()
            {
                public void run()
                {
                    mCount = (mCount + 1) % mMaximum;
                    repaint();
                }
            };
            Timer timer = new Timer();

            timer.schedule(task, 0, mInterval);
        }
    }

    /**
     * @param message The mMessage to set.
     */
    public void setMMessage(String message)
    {
        mMessage = message;
    }
    public void paint(Graphics g)
    {
        int theta = -(mCount * 360 / mMaximum);

        // Clear the whole screen.刷新整个屏幕
        g.setColor(255, 255, 255);
        g.fillRect(0, 0, mWidth, mHeight);

        // Now draw the pinwheel.
        g.setColor(128, 128, 255);
        /*
         * drawArc()参数详细内容
           mX - 要绘制弧的左上角的 x 坐标
           mY - 要绘制弧的左上角的 y 坐标。
           mRadius(1) - 要绘制弧的宽度。
           mRadius(2) - 要绘制弧的高度。
           参数5 - 开始角度。
           参数6 - 相对于开始角度而言，弧跨越的弧度。
         */
        g.drawArc(mX, mY, mRadius, mRadius, 0, 360);
        g.fillArc(mX, mY, mRadius, mRadius, theta + 90, 90);
        g.fillArc(mX, mY, mRadius, mRadius, theta + 270, 90);

        // Draw the message, if there is a message.
        if (mMessage != null)
        {
            g.drawString(mMessage, mWidth / 2, mHeight, Graphics.BOTTOM
                    | Graphics.HCENTER);
        }
    }

}