Linear layouts arrange their views in a single row or column. Each view is allocated its own space on the screen, and they don’t overlap one another.
Sometimes, however, you want your views to overlap. As an example, suppose you want to display an image with some text overlaid on top of it. You wouldn’t be able to achieve this just using a linear layout.
If you want a layout whose views can overlap, a simple option is to use a frame layout. Instead of displaying its views in a single row or column, it stacks them on top of each other. This allows you to, for example, display text on top of an image.
You define a frame layout using the
<FrameLayout> element like this:
Just like a linear layout, the
android:layout_height attributes are mandatory and specify the layout’s width and height.
We’re going to change _activitymain.xml so that it uses a frame layout containing an image view (a view that displays an image) and a text view. To do this, replace the code in your version of _activitymain.xml with ours below:
When you define a frame layout, you add views to the layout in the order in which you want them to be stacked. The first view is displayed first, the second is stacked on top of it, and so on. In our case, we’ve added an image view followed by a text view, so the text view appears on top of the image view:
By default, any views you add to a frame layout appear in the top-left corner. You can change the position of these views using the
android:layout_gravity attribute, just as you could with a linear layout.
As an example, here’s how you would move the text view to the bottom-end corner of the image:
One of the disadvantages of using a frame layout is that it’s easy for views to overlap one another when you don’t want them to. As an example, you may want to display two text views in the bottom-end corner, one above the other: