ImageView.getWidth() returns 0

Question

I get imageView's width 0. Below is code.

xml file :

<ImageView
        android:id="@+id/img"
        android:layout_width="200dp"
        android:layout_height="200dp" />

Activity :

@Override
protected void onResume() {
    super.onResume();
    ImageView img = (ImageView) findViewById(R.id.img);
    Log.d(TAG, "width : " + img.getWidth());
}

I don't want to use below code as I need to place this code in so many places.

ViewTreeObserver vto = img.getViewTreeObserver();
    vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
        public boolean onPreDraw() {
            ImageView img = (ImageView) findViewById(R.id.img);
                    Log.d(TAG, "width : " + img.getWidth());
            return true;
        }
    });

My workaround : I actually later did not need to add this code in an activity. I added it to a non-activity class and instead of ImageView's width I used Bitmap image's width and now does not have this problem.

Answer 1

Where you calling getWidth() and getHeight() on ImageView? If you calling from onCreate() in activity, it won't work. You need to wait for activity window to attached and then call getWidth() and getHeight() on ImageView. You can try calling getWidth() and getHeight() from onWindowFocusChanged() method of your activity.

call on onWindowFocusChanged like this way

public void onWindowFocusChanged(boolean hasFocus) {
    // TODO Auto-generated method stub
    super.onWindowFocusChanged(hasFocus);
     if (hasFocus) {
        ImageView img = (ImageView) findViewById(R.id.img);
        Log.d(TAG, "width : " + img.getWidth());
     }

    }

Answer 2

well i found many many questions related that are duplicate to this question, and most of the answers were not fit for my case.

I have come up with a solution that may fit for yours as it does for me. Simply, i have created a custom ImageView and added a new callback OnSizeChangedCallback that is being called whenever the size of the view is changed to non zero values.

Here's a code sample of my own:

public class AvatarImageView extends ImageView{

    private OnImageViewSizeChanged sizeCallback = null;

    public AvatarImageView(Context context) {
        super(context);
    }

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

    public AvatarImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        if (w == 0 || h == 0) {
            return;
        }
        else{
            if(sizeCallback != null)
                sizeCallback.invoke(this, w, h);
        }

    }

    public void setOnImageViewSizeChanged(OnImageViewSizeChanged _callback){
        this.sizeCallback = _callback;

        if (getWidth() != 0 && getHeight() != 0) {
            _callback.invoke(this, getWidth(), getHeight());
        }
    }

    public interface OnImageViewSizeChanged{
        public void invoke(ImageView v, int w, int h);
    }
}

and you can simply use it as follows:

final AvatarImageView avatarIcon = (AvatarImageView) findViewById(R.id.avatarImg);
avatarIcon.setOnImageViewSizeChanged(new AvatarImageView.OnImageViewSizeChanged() {
    @Override
    public void invoke(ImageView v, final int w, final int h) {
            // Do whatever you want with w and h which are non zero values ...
    }
});

related questions:

1. views-getwidth-and-getheight-returning-0
2. android-imageview-return-getwidth-getheight-zero
3. android-get-width-returns-0

Answer 3

Since you already have a "fixed" width imageView of 200dp why don't you just put it in dimens.xml

<dimen name="image_width">200dp</dimen>

and then simply

int width = (int) getResources().getDimension(R.dimen.image_Width)