A ConstraintLayout is a ViewGroup that allows you to position and size the layout's child views in a flexible way. In a ConstraintLayout, each view's position is defined using at least one horizontal constraint, and at least one vertical constraint*.* A constraint connects or aligns a view to another UI element, to the parent layout, or to an invisible guideline. Advantages of using ConstraintLayout:
You can make a ConstraintLayout responsive to devices that have different screen sizes and resolutions. ConstraintLayout usually results in a flatter view hierarchy than LinearLayout. The design editor and the view inspector in Android Studio help you add and configure constraints. Chains:
A chain is a group of views that are linked to each other with bidirectional constraints. The views within a chain can be distributed either vertically or horizontally. Design-time attributes:
Design-time attributes are used and applied only during the layout design, not at runtime. When you run the app, design-time attributes are ignored. Design-time attributes are prefixed with the tools namespace. For example, the tools:layout_editor_absoluteY and tools:text attributes are design-time attributes. Baseline constraints:
A baseline constraint aligns a view's text baseline to the text baseline of another view that has text. Baseline constraints are helpful when views have different font sizes.