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Building Android UIs with Custom Views by Raimon Ràfols Montané

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Extending a view

Using the example from the previous section, or just creating a new project with an Empty Activity if you've skipped it, we will change the TextView with our own implementation.

If we take a look at the default layout XML file, usually called activity_main.xml if you haven't changed it during project creation, we can see there is TextView inside a RelativeLayout:

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" ...

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