看代码学Android ：使用线程

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

public class TestView extends View implements Runnable
{

    static final int MSG_A = 100;

    private Handler m_handle = null;
    private float x, y;


    public TestView (Context context) {
        super(context);

        m_context = context;

        // 创建一个handle接收来自子线程的消息, 非常可靠！ 推荐！
        m_handle = new Handler() {
             public void handleMessage(Message msg) {
                 if (msg.what == MSG_A ) {
                     Toast.makeText(m_context, Integer.toString(x) + " " + Integer.toString(y), Toast.LENGTH_SHORT).show();
                  }
                 super.handleMessage(msg);
             }
         };

         // Run thread
         new Thread(this).start();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawLine(0, 0, x, y, null);
    }


    @Override
    public void run() {

        while( !Thread.currentThread().isInterrupted() )
        {
            try{

                Thread.sleep(100);
            }
            catch( InterruptedException e )
            {
                Thread.currentThread().interrupt();
            }

            x++;
            y++;                           // 子线程通知主线程重画canvas                 this.postInvalidate();

            if( x > 500.0f && y > 500.0f)
            {
                // 发送消息给主线程
                Message msg = new Message();
                msg.what = MSG_A;
                msg.arg1 = (int)x;
                msg.arg2 = (int)y;
                this.m_handle.sendMessage(msg);
            }


           x = 0.0f;
           y = 0.0f;

        }

    }

}