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code style

Sebastian edited this page 2020-12-07 17:55:43 +00:00

Table of Contents

• Avoid Staircase Indent
• Tab Size in Gitlab
• Static Imports

• Lines no longer than 80 characters
• Tabs for indentation, tab width of 4
• Egyptian brackets (else/catch/finally continue the same line as the preceding bracket)
• if/else/for/while may omit brackets if the body fits on a single line
• If the if uses brackets, the else should too (and vice versa)
• Use foo rather than mFoo, _foo, etc for field names
• Use foo rather than this.foo unless there's also a local foo
• CONSTANTS_LIKE_THIS, variablesLikeThis
• AbcCamelCase rather than ABCCamelCase

The configuration for Android Studio to format source files like this is checked into version control so that the formatter should apply this style out of the box (Using Ctrl+Alt+L).

Avoid Staircase Indent

Android Studio does not remove manual line breaks or line breaks that have been added by the formatter before. Sometimes, e.g. when adding arguments or renaming methods or variables, this can lead to staircase-like indent such as this:

someVariable
    .someMethod(
        new LongClassNameWithSomeParameters(int foo, long bar));

Please avoid this and help the formatter by manually removing the first line break:

someVariable.someMethod(
        new LongClassNameWithSomeParameters(int foo, long bar));

Tab Size in Gitlab

By default Gitlab expands tabs to 8 characters in source code and diff views rather than 4 that we use in Android Studio. As a result the code looks very different in the browser than in the IDE. You can configure your personal tab width in your Gitlab profile preferences (Scroll to Behavior → Tab width)

Static Imports

Please use static imports of methods and fields such as import static android.widget.Toast.LENGTH_LONG wherever possible so that you can write LENGTH_LONG instead of Toast.LENGTH_LONG. Exceptions are cases where a static import reduces clarity such as writing Builder instead of AlertDialog.Builder or MAX_VALUE instead of Integer.MAX_VALUE.