Android Studio 2018.3.20 user input

User input

Currency Exchange function

Mailbox Directory Program

Note: The scope of the variable (global variable, local variable)

Application of the Management questionnaire: Health Check can tell users how healthy they live

Global variables apply to values before they are saved, they are methods to save the application state, they are not suitable for saving the middle value of a variable

If your variable exists only within the code block, then it is not set as a global variable, he is used locally, he is only used in this method, the message is such a variable, it is an intermediate variable, only used at this time, so the message is not set to a global variable

When a global variable is set, but it is not given an initial value, it is given a default value, and for a string type, the default initial value is an empty string-that is, there is no text in a string

Thinking before setting up layouts: 1. Determine what to build (Textview,imageview,button)

2. Determine what viewgroup to use

3. Style your layout!

Android Studio 2018.3.20 user input