public class MainActivity extends Activity {
GrameView grameView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
grameView=new GrameView(this);
setContentView(grameView);
}
public boolean onKeyDown(int code,KeyEvent event) {
switch (code) {
case KeyEvent.KEYCODE_DPAD_DOWN:
grameView.y+=3;
break;
case KeyEvent.KEYCODE_DPAD_UP:
grameView.y-=3;
break;
default:
break;
}
return true;
}
}
package com.example.examples_05_02_01;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class GrameView extends SurfaceView implements SurfaceHolder.Callback,Runnable {
//控制循环
boolean mbLoop = false;
//定义SurfaceHolder对象
SurfaceHolder mSurfaceHolder = null;
int miCount = 0;
int y = 50;
public GrameView(Context context)
{
super(context);
// 实例化SurfaceHolder
mSurfaceHolder = this.getHolder();
// 添加回调
mSurfaceHolder.addCallback(this);
this.setFocusable(true);
mbLoop = true;
}
// 在surface的大小发生改变时激发
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height)
{
}
// 在surface创建时激发
public void surfaceCreated(SurfaceHolder holder)
{
//开启绘图线程
new Thread(this).start();
}
// 在surface销毁时激发
public void surfaceDestroyed(SurfaceHolder holder)
{
// 停止循环
mbLoop = false;
}
// 绘图循环
public void run()
{
while (mbLoop)
{
try
{
Thread.sleep(200);
}
catch (Exception e)
{
}
//加锁
synchronized( mSurfaceHolder )
{
Draw();
}
}
}
// 绘图方法
public void Draw()
{
//锁定画布，得到canvas
Canvas canvas= mSurfaceHolder.lockCanvas();
if (mSurfaceHolder==null || canvas == null )
{
return;
}
if (miCount < 100)
{
miCount++;
}
else
{
miCount = 0;
}
// 绘图
Paint mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(Color.BLACK);
//绘制矩形--清屏作用
canvas.drawRect(0, 0, 320, 480, mPaint);
switch (miCount % 4)
{
case 0:
mPaint.setColor(Color.BLUE);
break;
case 1:
mPaint.setColor(Color.GREEN);
break;
case 2:
mPaint.setColor(Color.RED);
break;
case 3:
mPaint.setColor(Color.YELLOW);
break;
default:
mPaint.setColor(Color.WHITE);
break;
}
// 绘制矩形--后面我们将详细讲解
canvas.drawCircle((320 - 25) / 2, y, 50, mPaint);
// 绘制后解锁，绘制后必须解锁才能显示
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
}