Android SurfaceView 的基本应用

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"android:layout_height="fill_parent"
android:orientation="vertical">

<LinearLayoutandroid:id="@+id/LinearLayout01"
android:layout_width="wrap_content"android:layout_height="wrap_content">
<Buttonandroid:id="@+id/Button01"android:layout_width="wrap_content"
android:layout_height="wrap_content"android:text="简单绘画"></Button>
<Buttonandroid:id="@+id/Button02"android:layout_width="wrap_content"
android:layout_height="wrap_content"android:text="定时器绘画"></Button>
</LinearLayout>
<SurfaceViewandroid:id="@+id/SurfaceView01"
android:layout_width="fill_parent"android:layout_height="fill_parent"></SurfaceView>
</LinearLayout>

packagecom.testSurfaceView;

importjava.util.Timer;
importjava.util.TimerTask;

importandroid.app.Activity;
importandroid.graphics.Canvas;
importandroid.graphics.Color;
importandroid.graphics.Paint;
importandroid.graphics.Rect;
importandroid.os.Bundle;
importandroid.util.Log;
importandroid.view.SurfaceHolder;
importandroid.view.SurfaceView;
importandroid.view.View;
importandroid.widget.Button;

publicclassTestSurfaceViewextendsActivity{
/**Calledwhentheactivityisfirstcreated.*/
ButtonbtnSimpleDraw,btnTimerDraw;
SurfaceViewsfv;
SurfaceHoldersfh;

privateTimermTimer;
privateMyTimerTaskmTimerTask;
intY_axis[],//保存正弦波的Y轴上的点
centerY,//中心线
oldX,oldY,//上一个XY点
currentX;//当前绘制到的X轴上的点

@Override
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

btnSimpleDraw=(Button)this.findViewById(R.id.Button01);
btnTimerDraw=(Button)this.findViewById(R.id.Button02);
btnSimpleDraw.setOnClickListener(newClickEvent());
btnTimerDraw.setOnClickListener(newClickEvent());
sfv=(SurfaceView)this.findViewById(R.id.SurfaceView01);
sfh=sfv.getHolder();

//动态绘制正弦波的定时器
mTimer=newTimer();
mTimerTask=newMyTimerTask();

//初始化y轴数据
centerY=(getWindowManager().getDefaultDisplay().getHeight()-sfv
.getTop())/2;
Y_axis=newint[getWindowManager().getDefaultDisplay().getWidth()];
for(inti=1;i<Y_axis.length;i++){//计算正弦波
Y_axis[i-1]=centerY
-(int)(100*Math.sin(i*2*Math.PI/180));
}
}

classClickEventimplementsView.OnClickListener{

@Override
publicvoidonClick(Viewv){

if(v==btnSimpleDraw){
SimpleDraw(Y_axis.length-1);//直接绘制正弦波

}elseif(v==btnTimerDraw){
oldY=centerY;
mTimer.schedule(mTimerTask,0,5);//动态绘制正弦波
}

}

}

classMyTimerTaskextendsTimerTask{
@Override
publicvoidrun(){

SimpleDraw(currentX);
currentX++;//往前进
if(currentX==Y_axis.length-1){//如果到了终点，则清屏重来
ClearDraw();
currentX=0;
oldY=centerY;
}
}

}

/**
*绘制指定区域
*/
voidSimpleDraw(intlength){
if(length==0)
oldX=0;
Canvascanvas=sfh.lockCanvas(newRect(oldX,0,oldX+length,
getWindowManager().getDefaultDisplay().getHeight()));//关键:获取画布
Log.i("Canvas:",
String.valueOf(oldX)+","+String.valueOf(oldX+length));

PaintmPaint=newPaint();
mPaint.setColor(Color.GREEN);//画笔为绿色
mPaint.setStrokeWidth(2);//设置画笔粗细

inty;
for(inti=oldX+1;i<length;i++){//绘画正弦波
y=Y_axis[i-1];
canvas.drawLine(oldX,oldY,i,y,mPaint);
oldX=i;
oldY=y;
}
sfh.unlockCanvasAndPost(canvas);//解锁画布，提交画好的图像
}

voidClearDraw(){
Canvascanvas=sfh.lockCanvas(null);
canvas.drawColor(Color.BLACK);//清除画布
sfh.unlockCanvasAndPost(canvas);

}
}