ImageView Custom Image Program

Question

I am creating a small Android application where I have a RelativeLayout, which, among other things, contains a custom ImageView. In my Java code, I have this class:

package com.example.android.helloactivity;


class ArrowImageView extends ImageView {
    public ArrowImageView(Context context) {
        super(context);
    }
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(10,10,10,null);
    }
}

Then in my RelativeLayout xml I have the following:

<RelativeLayout android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="vertical"
            android:background="#FFF"
            xmlns:android="http://schemas.android.com/apk/res/android">
    <Button ...... />
    <TextView ......./>

    <com.example.android.helloactivity.ArrowImageView
        android:id="@+id/hello_activity_bearingarrow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</RelativeLayout>

When I run my main class (not shown here), my program will work. If I omit the xml link to ArrowImageView, this is not a failure.

I mean my custom class or the wrong way, or what happens?

Answer 1

View, XML-, , AttributeSet.

Answer 2

ImageView, View, - ImageView, .

-, , ,

public ArrowImageView(Context context, AttributeSet set) {         
 super(context, set);     
} 

, , witdh height - 100dp. , "", .

Answer 3

. onPaint, . onPaint :

public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Paint paint = new Paint();
    paint.setColor(Color.MAGENTA);
    canvas.drawCircle(10,10,10,paint);
}

! : -)