Android Layouts

Introduction

View Hierarchy can be split into types types

• Margin is the space around the widget
• Padding is the space within the widget
• Gravity is the position of the widget within the widget its self
• Layout Gravity is the position of the widget within its parent

Here shows the difference between layout_gravity and gravity.

Layouts

Linear

These are like rows and columns in flex box. Items are wapped.

Weight

Weight determines the distribution of the widgets when no width or height is provided. Here the weight adds up to 3 and therefore the ratio is 1:2

FrameLayout

This allows you to put a layout on top of another. E.g. you want of put text on top of a picture.

Coordinated Layout

Intended for two primary use cases

• As a top level application decor or chrome-layout
• As a container for a specific interaction
  • With its child views
  • Between its child views

This can be used as parent which will allow other components such as the FAB button to move when the SnackBar appears. The example of collapsing toolbar was very impressive.

Constraint Layout

• Released in 2016
• Compatible with API 9+
• Can be used for animations
• Flat hierarchy so no nested layouts (better performance)
• Provides relative positioning
• You can use drag and drop in Visual Studio

When you use android studio you can convert existing layouts in the component tree by right clicking. This does not always work but is an option By using the Android Studio Editor you can drag the constraints to the sides so constrain the widget.
You can add Guidelines to attach to for extra constraints. e.g. for dividing a layout by 50%. These do not show to the user.