我正在尝试将自定义surfaceView 类添加到已在xml 布局中声明的surfaceView。问题是我无法让自定义类添加xml定义的surfaceView。一些它只是没有开始。
这是我的代码:
MainActivity
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sineWaveSurfaceView = (SineWaveSurfaceView) findViewById(R.id.surfaceView);
}
MainActivity 布局
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<mark.dijkema.android.eindopdracht.SineWaveSurfaceView
android:id="@+id/surfaceView"
android:layout_width="fill_parent"
android:layout_height="100dp"
android:layout_marginTop="20dp" />
<ListView
android:id="@+id/song_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp" >
</ListView>
</RelativeLayout>
SineWaveSurfaceView 类
public class SineWaveSurfaceView extends SurfaceView implements SurfaceHolder.Callback
{
private Context context;
public SineWaveSurfaceView(Context context)
{
super(context);
// TODO Auto-generated constructor stub
this.context = context;
getHolder().addCallback(this);
Log.e("constructor", "done");
}
public SineWaveSurfaceView(Context context, AttributeSet attrs)
{
super(context, attrs);
// TODO Auto-generated constructor stub
}
public SineWaveSurfaceView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
protected void OnDraw(Canvas canvas, int value)
{
//canvas.drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setColor(Color.WHITE);
float y = Float.valueOf(String.valueOf(value));
for(float x = 0; x < 200; x += 0.1f)
{
canvas.drawPoint(x, y, paint);
}
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3)
{
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder arg0)
{
// TODO Auto-generated method stub
Log.e("start", "started");
}
@Override
public void surfaceDestroyed(SurfaceHolder arg0)
{
// TODO Auto-generated method stub
}
}
问题是 Log.e("constructor", "done"); 在 SineWaveSurfaceView 的构造函数中甚至没有出现。
我做错了什么,因为当我做类似的事情时
sineWaveSurfaceView = new sineWaveSurfaceView(this);
然后它可以工作,但它没有附加到xml布局中定义的surfaceView。