CODEWITHSUNDEEP
android
Saar Kuriel
Saar Kuriel

Reputation: 582

findViewById for Custom view I've created

I'm new to android development.

I've built a MarakableImageView for drawing a circle on an image by tapping on it.

public class MarkableImageView extends ImageView {
    ArrayList<Marker> mMarkers;

    public MarkableImageView(Context context, AttributeSet attrs){
        super(context, attrs);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        paint.setColor(Color.RED);
        paint.setStyle(Paint.Style.FILL_AND_STROKE);
        for(Marker m : mMarkers){
            // TODO: Draw the marker
            canvas.drawCircle(m.x, m.y, 3, paint);
        }

    }

    public boolean onTouchEvent(MotionEvent e) {
        if (e.getAction() == MotionEvent.ACTION_DOWN) {
            mMarkers.add(new Marker(e.getX(), e.getY()));
            invalidate();
            return true;
        }
        return false;
    }

    public void reset() {
        mMarkers.clear();
        invalidate();
    }

    // this class will be visible only inside MarkableImageView
    private class Marker {
        public float x;
        public float y;
        // you might want to add other properties, for example
        // if you need to have different types of markers

        public Marker(float x, float y) {
            this.x = x;
            this.y = y;
        }
    }
}

and to use it in my code I've used:

is = getContentResolver().openInputStream(selectedImageUri);
MarkableImageView iv = (MarkableImageView) findViewById(R.id.imageView);
Bitmap bmp = BitmapFactory.decodeStream(is);
iv.setImageBitmap(bmp);

My problem occurs in the second line of the second code section above, because in content_main.xml imageView appears as ImageView and not MarkableImageView.

What do I need to fix?

Upvotes: 2

Views: 239

Answers (1)

Blackbelt
Blackbelt

Reputation: 157457

My problem occurs in the second line of the second code section above, because in content_main.xml imageView appears as ImageView and not MarkableImageView.

you have to declare it in your xml, specifying the fully qualified path to your class (have a look here). E.g. 

<com.example.customviews.MarkableImageView

please be aware that your ArrayList<Marker> mMarkers; is never instantiated. This will make your app crash for NPE

Upvotes: 2

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