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我正在編寫一個應用程序，該應用程序應該在按鈕等下面的屏幕底部的畫布中繪製一條線。我的佈局顯示出來，但是該線不顯示。任何人都知道爲什麼我的畫布不顯示？爲什麼我的畫布不會顯示（Android）？
下面是代碼：
public class Vectors extends Activity{
VectorsView vectorsView;
LinearLayout l;
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.vectors);
vectorsView = new VectorsView(this);
l = (LinearLayout) findViewById(R.id.llCanvasV);
l.addView(vectorsView);
.......
}
public class VectorsView extends View{
public VectorsView(Context context) {
super(context);
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
Paint paint = new Paint();
paint.setColor(Color.WHITE);
canvas.drawLine(0, 0, 100, 100, paint);
vectorsView.draw(canvas);
vectorsView.setLayoutParams(new LayoutParams(25, 25));
}
}
下面是XML：
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/background"
android:orientation="vertical">
<ImageView android:layout_height="wrap_content"
android:src="@drawable/vectors"
android:layout_width="wrap_content"
android:layout_gravity="center"
android:paddingTop="5dp"
android:paddingBottom="5dp"
android:adjustViewBounds="true">
</ImageView>
<LinearLayout android:layout_height="wrap_content"
android:layout_width="match_parent"
android:orientation="horizontal">
<Button android:text="Choose Program"
android:id="@+id/bChsProgV"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_marginLeft="97dp"
android:adjustViewBounds="true">
</Button>
<ImageButton android:layout_height="wrap_content"
android:src="@drawable/help"
android:id="@+id/ibHelpV"
android:layout_width="wrap_content"
android:layout_marginLeft="65dp"
android:background="@null"
android:layout_marginTop="10dp">
</ImageButton>
</LinearLayout>
<LinearLayout android:id="@+id/llCanvasV"
android:layout_height="wrap_content"
android:layout_width="match_parent">
</LinearLayout>
</LinearLayout>