android中View类的开发框架

核心提示：mGameSurfaceView.y-=3;break;case KeyEvent.KEYCODE_DPAD_DOWN:mGameSurfaceView.y+=3;break;}return true;}}package com.gameview;import android.R.drawable;import and

mGameSurfaceView.y-=3;

break;

case KeyEvent.KEYCODE_DPAD_DOWN:

mGameSurfaceView.y+=3;

break;

}

return true;

}

}

package com.gameview;

import android.R.drawable;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Path;

import android.graphics.Rect;

import android.graphics.RectF;

import android.util.Log;

import android.view.View;

public class GameView extends View {

int miCount = 0;

int y = 0;

public GameView(Context context) {

super(context);

// TODO Auto-generated constructor stub

}

public void onDraw(Canvas canvas)

{

if(miCount<100)

{

miCount++;

}

else

{

miCount = 0;

}

Paint mPaint = new Paint();

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;

}

//paint the rectangle

canvas.drawRect((500-80)/2, y, (500-80)/2+80, y+40, mPaint);

}

}

我们通过onDraw来绘制图，用invalidate的方法来实现界面的刷新，注意invalidate不能直接在进程中调用，因为它违背了单线程的模式：android的UI操作并不是线程安全的，并且这些操作必须在UI线程当中执行，因此android中最常用的方法是利用Handler来实现UI进程的更新