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It's All Relative

Android Snippets - Relative Layouts

If you want your scrollable lists in your Android Applications to be smooth and responsive, then you need to know how to use a RelativeLayout.

Using a RelativeLayout may seem a little daunting and complicated at first - especially when the UI you are attempting to layout has many elements. However there are only really two things you need to remember:

  1. you cannot reference an element before it has been declared
  2. work your way through your layout and identify how your UI Elements are to be presented:
    • Relative to the Container
    • Relative to other Elements
    • Aligned to other Elements

Relative To Container
These properties layout elements relative to the parent container.
android:layout_alignParentBottom positions the bottom of the element on the bottom of the container
android:layout_alignParentLeft positions the left of the element on the left side of the container
android:layout_alignParentRight positions the right of the element on the right side of the container
android:layout_alignParentTop positions the element at the top of the container
android:layout_centerHorizontal centers the element horizontally within its parent container
android:layout_centerInParent centers the element both horizontally and vertically within its container
android:layout_centerVertical centers the element vertically within its parent container
Relative To Other Elements
These properties allow you to layout elements relative to other elements on screen. The value for each of these elements must defined using android:id=”@+id/myelementlabel”, and as mentioned earlier, you can not reference an element before it has been declared.
android:layout_above positions the element above the specified element
android:layout_below positions the element below the specified element
android:layout_toLeftOf positions the element to the left of the specified element
android:layout_toRightOf positions the element to the right of the specified element
Aligned to other Elements
These properties allow you to specify how elements are aligned in relation to other elements.
android:layout_alignBaseline aligns the baseline of your element with the baseline of the specified element.
android:layout_alignBottom aligns the bottom of your element in with the bottom of the specified element
android:layout_alignLeft aligns left edge of your element with the left edge of the specified element
android:layout_alignRight aligns right edge of your element with the right edge of the specified element
android:layout_alignTop positions top of the your element in alignment with the top of the specified element

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