Android How to Program, 3/e

3.1 Introduction

The Tip Calculator app (Fig. 3.1(a)) calculates and displays the tip and total for a restaurant bill amount. As you touch the numeric keypad to enter the bill amount’s digits, the app calculates and displays the tip and total bill amounts for the current tip percentage (15% by default). You specify a tip percentage from 0% to 30% by moving the SeekBar thumb—this updates the displayed tip percentage and recalculates the tip and total. All numeric values are displayed using locale-specific formatting. Figure 3.1(b) shows the app after the user enters the amount 56.32 and changes the tip percentage to 25%.

Fig. 3.1 Entering the bill total and calculating the tip

Figure 3.1 Full Alternative Text

You’ll begin by test-driving the ...