Differencebetween Src and Background of Imageview

Difference between src and background for image view

But both are looking differnt

First, the drawables are different.

Second, the background always scales to the size of the view.

when i press the imageview with background set it is not showing the selection. can anyone explain why this happens

The selection effect is because by default, the background is a StateListDrawable with a different appearance in state_pressed. Your custom background looks the same in all states. You can create StateListDrawables in xml with a selector.

What is the difference between ImageView.setBackgroundResource and ImageView.setImageResource?

setBackgroundResource is for setting the background of an ImageView.

setImageResource is for setting the src image of the ImageView.
Given:

ImageView iv = new ImageView(this);

Then:

iv.setBackgroundResource(R.drawable.imagedata);

Will fit the image for the entire background. That means it will stretch the image to fill that background entirely even if the image size is too small.

imageView.setImageResource(R.drawable.imagedata);

Will occupy only the size of the image in ImageView.
For that you want to also set

android:layout_width="wrap_content"
android:layout_height="wrap_content"

for your ImageView. If the size of the image is smaller than the ImageView the remaining border will be left blank and the background will be shown.

Difference between app:srcCompat and android:src in Android's layout XML

app:srcCompat

is the most foolproof method of integrating vector drawables into your app.Vector drawables allow you to replace multiple png assets with a single vector graphic, defined in XML. While previously limited to Lollipop and higher devices

Note

As of Android Support Library 23.3.0, support vector drawables can only be loaded via app:srcCompat .

you need to add vectorDrawables.useSupportLibrary = true to your build.gradle file

    // Gradle Plugin 2.0+  
 android {  
   defaultConfig {  
     vectorDrawables.useSupportLibrary = true  
    }  
 }  

android:src

Sets a drawable as the content of this ImageView.It will display in
its original size. No automatic scaling .

Difference(s): android:src and tools:src?

If you are using android:src in xml during runtime this will show up on the app, whereas if you use tools:src in xml it will show only on the preview of Android studio and not on the runtime of the app.

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