Question

I have a custom class that extends ImageView

    public class MyCompass extends ImageView 
    {
         private float direction;
// Rest Code

    }
      <ImageView class="myPakagename.MyCompass"
                android:layout_centerInParent="true"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/immg"
                android:src="@drawable/hub"/>

I am trying to call this in my fragment as

   myCompass = (MyCompass) view.findViewById(R.id.immg);

However this gives me classCastException. How can i make my Class extends ImageView?

@SuppressLint("DrawAllocation")
public class MyCompass extends ImageView 
{
     private float direction;

     public MyCompass(Context context) 
     {
      super(context);
      setImageResource(R.drawable.qibla_compass_hub);
     }

     public MyCompass(Context context, AttributeSet attrs) {
      super(context, attrs);
      this.setImageResource(R.drawable.qibla_compass_hub);        
      }

     public MyCompass(Context context, AttributeSet attrs, int defStyle) {
      super(context, attrs, defStyle);
      this.setImageResource(R.drawable.qibla_compass_hub);                                
      }

     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      setMeasuredDimension(
        MeasureSpec.getSize(widthMeasureSpec),
        MeasureSpec.getSize(heightMeasureSpec));
     }

     @Override
     protected void onDraw(Canvas canvas) {
      int w = getMeasuredWidth();
      int h = getMeasuredHeight();
      canvas.rotate(direction, w / 2, h / 2);

     }

     public void update(float dir){
      direction = dir;
      invalidate();
     }

My layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/qiblaBg"
    android:background="@drawable/qibla_bg">    

    <RelativeLayout 
        android:layout_centerInParent="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/qibla_compass_outer">

          <mypakage.MyCompass
              android:contentDescription="@string/qibla"
                    android:layout_centerInParent="true"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:id="@+id/qiblaImg"

// android:src=@”img” doesn’t work but android:background works however it again stretches to full screen.
/>

                            <RelativeLayout 
                                android:id="@+id/qiblaArrow"
                                android:layout_centerInParent="true"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:orientation="vertical" 
                                android:background="@drawable/qibla_compass_arrow" />      
    </RelativeLayout>


</RelativeLayout>

Using this, my MyCompass ImageView in layout stretches to full screen and Does’t show any image.

Answer 1

You can refer to your custom image view in the xml directly using:

<myPakagename.MyCompass
            android:layout_centerInParent="true"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/immg"
            android:src="@drawable/hub"/>

And make sure that your custom view overrides:

public MyCompass(Context context) {}

And

public MyCompass(Context context, AttributeSet attrs) {}

And

public MyCompass(Context context, AttributeSet attrs, int defStyle) { }