Fit Image in ImageButton in Android

Question

I have 6 ImageButton in my activity, I set images through my code in them ( not using xml).

I want them to cover 75% of the button area. But where as some images cover less area, some are too big to fit into the imageButton. How to programatically resize and show them? Below is the screen shot

below is the xml-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"
    android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"     >
   <LinearLayout
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">
        <ImageButton          

            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:id="@+id/button_topleft"
        android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"
            />
        <ImageButton
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:id="@+id/button_topright"
    android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"
            />
    </LinearLayout>
    <LinearLayout
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <ImageButton
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:id="@+id/button_repeat"
    android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"     
             />

              <ImageButton
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:id="@+id/button_next"
    android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"     
             />

    </LinearLayout>    
   <LinearLayout
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <ImageButton
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:id="@+id/button_bottomleft"
    android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"                                 
             />
        <ImageButton
            android:layout_height="match_parent"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:id="@+id/button_bottomright"
    android:layout_marginBottom="5sp"
        android:layout_marginLeft="2sp"
        android:layout_marginRight="5sp"
        android:layout_marginTop="0sp"                  
            />        
    </LinearLayout>        

</LinearLayout>

and a snippet of myClass.java:

public void addImageButtons()
    {
        iB_topleft = (ImageButton) findViewById(R.id.button_topleft);
        iB_topright = (ImageButton) findViewById(R.id.button_topright);
        iB_bottomleft = (ImageButton) findViewById(R.id.button_bottomleft);
        iB_bottomright = (ImageButton) findViewById(R.id.button_bottomright);
        iB_next = (ImageButton) findViewById(R.id.button_next);
        iB_repeat = (ImageButton) findViewById(R.id.button_repeat);
    }

    public void setImageNextAndRepeat()
    {

    iB_topleft .setImageResource(R.drawable.aa);
        iB_topright.setImageResource(R.drawable.bb);   

    iB_bottomleft.setImageResource(R.drawable.cc);
        iB_bottomright.setImageResource(R.drawable.dd);   

        iB_next.setImageResource(R.drawable.next);
        iB_repeat.setImageResource(R.drawable.repeat);      
    }

Answer 1

I want them to cover 75% of the button area.

Use android:padding="20dp" (adjust the padding as needed) to control how much the image takes up on the button.

but where as some images cover less area, some are too big to fit into the imageButton. How to programatically resize and show them?

Use a android:scaleType="fitCenter" to have Android scale the images, and android:adjustViewBounds="true" to have them adjust their bounds due to scaling.

All of these attributes can be set in code on each ImageButton at runtime. However, it is much easier to set and preview in xml in my opinion.

Also, do not use sp for anything other than text size, it is scaled depending on the text size preference the user sets, so your sp dimensions will be larger than your intended if the user has a "large" text setting. Use dp instead, as it is not scaled by the user's text size preference.

Here's a snippet of what each button should look like:

    <ImageButton
        android:id="@+id/button_topleft"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_marginBottom="5dp"
        android:layout_marginLeft="2dp"
        android:layout_marginRight="5dp"
        android:layout_marginTop="0dp"
        android:layout_weight="1"
        android:adjustViewBounds="true"
        android:padding="20dp"
        android:scaleType="fitCenter" />