Android: How to programatically change the width of an ImageView without resizing its image?

Question

I am trying to programatically change the width of an ImageView without resizing the image. The ImageView originally shows the entire image, but when the width of the image is decreased, a portion of the image should be cut off, like this:

However, when my code reduces the width of the ImageView from 350dp to 200dp , the image is automatically resized instead:

How do I ensure that the ImageView does not resize the image when I decrease its width? Below is my code:

activity_main.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <ImageView
        android:id="@+id/photo_1_preview"
        android:layout_width="350dp"
        android:layout_height="350dp"
        android:adjustViewBounds="false"
        android:background="@drawable/android"/>
</LinearLayout>

MainActivity.java :

package com.example.changingimageviewwidth;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Reduce the width of the image preview box
        ImageView imagePreviewBox = findViewById(R.id.photo_1_preview);
        imagePreviewBox.getLayoutParams().width = 250;
    }
}

Answer 1

Set the scale type to CENTER_CROP. That will center the image in the view, and crop out anything that doesn't fit.

Answer 2

To get your desired behavior, simply set android:scaleType="fitStart" to your ImageView in xml. It will not change the aspect ratio of the src, but aligns it to the start of the ImageView, just as you mentioned.

Answer 3

The problem you're facing is because the drawable is set as a background of ImageView instead of being set as a source

After you fix that, the right scaleType to choose for your use-case is fitStart which will maintain the original aspect ratio for the bitmap and align it to the top-left of the ImageView

Please use the updated layout file -

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/photo_1_preview"
        android:layout_width="350dp"
        android:layout_height="350dp"
        android:adjustViewBounds="false"
        android:scaleType="fitStart"
        android:src="@drawable/android"/>

</LinearLayout>

Answer 4

• Use android:scaleType="matrix" for the ImageView and put the desired image in android:src .

NOTE : In this case, I set the LinearLayout to be 400x400 because the image size is 400x400 px and wrap the ImageView inside of a LinearLayout just for clarity.

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#333333"
    android:gravity="center"
    android:orientation="vertical">

    <LinearLayout
        android:layout_height="400px"
        android:layout_width="400px"
        android:orientation="vertical"
        android:background="#0000FF">

        <ImageView
            android:layout_height="match_parent"
            android:layout_width="match_parent"
            android:src="@drawable/android"
            android:scaleType="matrix"
            android:id="@+id/iv"/>

    </LinearLayout>

</LinearLayout>

MainActivity.java

public class MainActivity extends Activity 
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        ImageView iv = findViewById(R.id.iv);
        ViewGroup.LayoutParams params = iv.getLayoutParams();
        params.width = 200; //200 pixels.
        //Not necessary in my test. You may need to call the following
        //method if you set the params outside of onCreate(), onCreateView().
        //iv.requestLayout();
    }
}

Output:

Answer 5

Try with the following code.

  //activity_main.xml
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/darker_gray"
android:gravity="center"
android:orientation="vertical">

<ImageView
    android:id="@+id/image_view"
    android:layout_width="300dp"
    android:layout_height="300dp"
    android:scaleType="fitCenter"
    android:src="@drawable/dumy" />

</LinearLayout>


//MainActivity.java
 public class MainActivity extends AppCompatActivity {
 private ImageView imageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    imageView = findViewById(R.id.image_view);
    imageView.getLayoutParams().width = dpToPixels(150);
    imageView.requestLayout();
    imageView.invalidate();
}

private int dpToPixels(int size) {
    return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, size, getResources().getDisplayMetrics());
}
}