我有一个小问题是我到目前为止的代码:
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new GraphicView(this));
TextView mainLabel = (TextView)findViewById(R.id.title);
mainLabel.setText("Android Circle Path");
}
static class GraphicView extends View{
public GraphicView(Context context){
super(context);
}
@Override
public void onDraw(Canvas canvas){
}
}
}
和 main.xml 文件:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="30dip"
>
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="20dip"
android:layout_marginRight="20dip">
<TextView
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="20dip"
android:textSize="24.5sp"
android:id="@+id/title">
</TextView>
</LinearLayout>
</LinearLayout>
当我尝试在 onDraw() 函数中设置文本时,应用程序崩溃了,我做错了什么?