Android How to Program, 3/e

3.4 Building the GUI

In this section, we’ll show the precise steps for building the Tip Calculator’s GUI, including how to customize the Material theme’s primary and accent colors.

3.4.1 GridLayout Introduction

This app uses a GridLayout (package android.widget) to arrange views into four rows and two columns, each indexed from 0 like the elements in an array. You can specify a Grid-Layout’s number of rows and columns in the Properties window. Each cell can be empty or can hold one or more views, including layouts containing other views. A row’s height is determined by the row’s tallest view. Similarly, a column’s width is defined by the column’s widest view. Figure 3.2 shows the Tip Calculator’s GridLayout labeled by its rows and columns—we ...