How do you setLayoutParams() for an ImageView?

开发者_高级运维

I want to set the LayoutParams for an ImageView but cant seem to find out the proper way to do it.

I can only find documentation in the API for the various ViewGroups, but not an ImageView. Yet the ImageView seems to have this functionality.

This code doesn't work...

myImageView.setLayoutParams(new ImageView.LayoutParams(30,30));

How do I do it?

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You need to set the LayoutParams of the ViewGroup the ImageView is sitting in. For example if your ImageView is inside a LinearLayout, then you create a

LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(30, 30);
yourImageView.setLayoutParams(layoutParams);

This is because it's the parent of the View that needs to know what size to allocate to the View.

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Old thread but I had the same problem now. If anyone encounters this he'll probably find this answer:

LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(30, 30);
yourImageView.setLayoutParams(layoutParams);

This will work only if you add the ImageView as a subView to a LinearLayout. If you add it to a RelativeLayout you will need to call:

RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(30, 30);
yourImageView.setLayoutParams(layoutParams);

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If you're changing the layout of an existing ImageView, you should be able to simply get the current LayoutParams, change the width/height, and set it back:

android.view.ViewGroup.LayoutParams layoutParams = myImageView.getLayoutParams();
layoutParams.width = 30;
layoutParams.height = 30;
myImageView.setLayoutParams(layoutParams);

I don't know if that's your goal, but if it is, this is probably the easiest solution.

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An ImageView gets setLayoutParams from View which uses ViewGroup.LayoutParams. If you use that, it will crash in most cases so you should use getLayoutParams() which is in View.class. This will inherit the parent View of the ImageView and will work always. You can confirm this here: ImageView extends view

Assuming you have an ImageView defined as 'image_view' and the width/height int defined as 'thumb_size'

The best way to do this:

ViewGroup.LayoutParams iv_params_b = image_view.getLayoutParams();
iv_params_b.height = thumb_size;
iv_params_b.width = thumb_size;
image_view.setLayoutParams(iv_params_b);

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In order not to lose the rest of the parameters, you need to do as shown below:

Drawable drawable = ResourcesCompat.getDrawable(getResources(), R.drawable.checked, null);    
preview.setImageDrawable(drawable);
ViewGroup.LayoutParams layoutParams = preview.getLayoutParams();
layoutParams.width = 100;
layoutParams.height = 98;
preview.setLayoutParams(layoutParams);