Android FAB plus sign not present on android drawable

Where can I find the plus sign at the center of a Floating Action Button?

Is it made by Android or do I need to do it by my self?

You can find the plus icon on the Vector Asset Studio.

1. In Android Studio, open an Android app project.
2. In the Project window, select the Android view.
3. Right-click the res folder and select New > Vector Asset.
4. Click the Android icon Button and look for the plus sign

More info here: https://developer.android.com/studio/write/vector-asset-studio.html#materialicon

You can get the Material Icons:

1.Online - from the Material Design Website. The plus icon is called 'add'. Select the icon, pick a colour & size and download the png or svg resource.

2.From Android Studio - using Vector Asset Studio. Check the link for more information. (as suggested by Wilder Pereira in the post below)

based on @Dagnogo's answer, I found this is the simplest way.

    <android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    app:srcCompat="@android:drawable/ic_input_add"
    android:tint="@android:color/white"/>

The key is using tint property

If you need to change the color change the tint method on the fab. For example I needed the "white plus" in my fab so I did that :

<android.support.design.widget.FloatingActionButton
    android:layout_width="wrap_content"
    android:tint="@android:color/white" //put your colors here
    android:src="@drawable/ic_add_black_24dp"
    android:layout_height="wrap_content" />

I think you are searching for this.

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="end|bottom"
    android:layout_margin="@dimen/fab_margin"
    app:srcCompat="@android:drawable/ic_input_add" />

In 2021, if you want to change the colour of the button, then you need to use the app:tint property over android:tint.

Also, I recommend using app:srcCompat over android:src for better support of vectors.

For better accessibility support, it's important to use the android:contentDescription attribute.

Finally, you can use built-in drawables by using the @android:drawable/ prefix.

Putting it all together:

<com.google.android.material.floatingactionbutton.FloatingActionButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="32dp"
            android:contentDescription="Add a new item"
            app:tint="@android:color/white"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:srcCompat="@android:drawable/ic_input_add" />