How to create a rhombus shaped button in android studio

Question

I want to create a button with a rhombus shape like on the Material website :

(This is the picture)

I searched the web and didn't find an answer so I'm asking it here.

I already found out how to create a rhombus shape:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item
    android:height="60dp"
    android:width="60dp"

    android:right="20dp"
    android:left="20dp"
    android:gravity="center">
    <rotate
        android:fromDegrees="45"
        android:pivotX="50%"
        android:pivotY="50%" >
        <shape
            android:shape="rectangle">
            <solid
                android:color="@color/black" />
        </shape>
    </rotate>
</item>

and this is my Image Button :

<ImageButton
    android:layout_width="85dp"
    android:layout_height="85dp"
    android:background="@drawable/button_test"
    android:src="@drawable/ic_pause_white"
    />

"@drawable/ic_pause_white" is a pause icon vector I imported.

Now I have a pause button with a rhombus shape but my problem is that the hitbox doesn't match the image (like expected)

I already tried to create an OnTouchListener

ImageButton btnPlay = findViewById(R.id.btnPlay_Song);

btnPlay.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {

        int eventPadTouch = event.getAction();
        float iX=event.getX();
        float iY=event.getY();

        switch (eventPadTouch) {

            case MotionEvent.ACTION_DOWN:
                bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.button_test);

                if (iX>=0 & iY>=0 & iX<bitmap.getWidth() & iY<bitmap.getHeight()) { //Makes sure that X and Y are not less than 0, and no more than the height and width of the image.
                    if (bitmap.getPixel((int) iX, (int) iY)!=0) {
                        // actual image area is clicked(alpha not equal to 0), do something
                        Toast.makeText(ActivityPlayerSong.this, "Play", Toast.LENGTH_SHORT).show();
                    }
                }
                return true;
        }
        return false;
    }
});

but I was wondering if there is an easier method to do it and if there isn't using the code above "BitmapFactory.decodeResource(getResources(), R.drawable.button_test)" is returning null and I don't know why.

Thank You in advance to everyone who tries to help me!

Answer 1

An alternative to a more "technically correct" solution: What if you used a square background and then rotated the icon 45 degrees clockwise and rotated the whole button 45 degrees counter-clockwise?

layout.xml

<ImageButton
    android:background="@color/black"
    app:srcCompat="@drawable/ic_camera_45deg"
    android:rotation="-45"
    android:layout_width="48dp"
    android:layout_height="48dp"/>

Here the background is a solid color so you won't get any visual touch feedback. You'll want to use a <selector> drawable on Android 4 and <ripple> drawable on Android 5+ for that.

drawable/ic_camera_45deg.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
        android:width="24dp"
        android:height="24dp"
        android:tint="@color/white"
        android:viewportHeight="24.0"
        android:viewportWidth="24.0">

    <group
        android:pivotX="12"
        android:pivotY="12"
        android:rotation="45">
        <!-- Original paths go here. -->
    </group>
</vector>

Notice the tint attribute. Make sure the pivot point is in the middle of viewportWidth and viewportHeight if your icon is not 24x24.