RelativeLayout gravity center not working

Question

I'm trying to horizontally center several views in a RelativeLayout that is a base.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="center_horizontal"
    android:background="@android:color/transparent" >

This isn't working. I have set centerInParent to true for one of the views and that did work. However, I can't use this solution because I have 2 views side by side that need to be centered together. Trying to optimize this so I want to avoid nesting layouts, especially Linear, inside of each other.

Is there something obvious that I'm missing? I thought this attribute is made for this situation.

Omnidirectional

Answer 1

I answered a similar issue involving three views without using nested ViewGroups.

https://mcmap.net/q/396148/-center-multiple-items-in-a-relativelayout-without-putting-them-in-a-container

This is tested in API 11.

For the two view horizontal case:

<RelativeLayout
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:gravity="center"
  android:background="@android:color/black"
  >
  <Button
    android:id="@+id/apply"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="APPLY"
    android:textSize="20sp"
    />
  <Button
    android:id="@+id/undo"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="UNDO"
    android:textSize="20sp"
    android:layout_toRightOf="@id/apply"
    />
</RelativeLayout>

For the two view vertical case:

<RelativeLayout
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:gravity="center"
  android:background="@android:color/black"
  >
  <Button
    android:id="@+id/apply"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="APPLY"
    android:textSize="20sp"
    />
  <Button
    android:id="@+id/undo"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="UNDO"
    android:textSize="20sp"
    android:layout_below="@id/apply"
    />
</RelativeLayout>

Mesocarp

This solution only works when the views can be stacked in a single line, if the layout is more complex, the only solution is to use nested layouts as the other answers suggest or take a different apprach. – Beeler

@Mesocarp using For the two view horizontal case: does not perfectly center align both the views as it would when using a nested linear layout with orientation set to horizontal and gravity center – Elope

Answer 2

You'll need to nest several layouts together. To center something in a RelativeLayout, you use android:layout_centerInParent="true" on the child. If you try to center several childs, they'll end up under/over each other.

Therefore, for example, you could use a LinearLayout with two views as a child to the RelativeLayout, with the LinearLayout having android:orientation="horizontal" and android:layout_centerInParent="true". The LinearLayout should now be centered in the RelativeLayout, with the two children next to each other.

Hypha

I'm really trying to optimize this screen since it's the main activity. Therefor I'm really really trying to avoid nesting LinearLayouts. I actually removing all the linearlayouts from this apps since they are terrible inefficient. – Omnidirectional

Well, there's no way to do it (good looking) if you cannot nest layouts. At least as far as I know. – Hypha

Answer 3

Wrap the two views in a LinearLayout and then center the LinearLayout in the RelativeLayout like you did for the single TextView.

Aurify

Don't want to nest. And that still doesn't explain the issue that centerInParent works when set to true, but is not working when gravity is set to center_horizontal – Omnidirectional

Try android:layout_gravity="center horizontal" on your text views. – Aurify

No. Thanks for the reply, but that isn't going to work. I need two buttons to be side-by-side so center_horizontal for each will put them on top of each other. – Omnidirectional

Then you need to nest layouts. There is no performance hit to that unless you try to nest views using layout_weight. – Aurify

Actually, you can center in parent and then manipulate the position using margins and the align the other textview to that one if you are determined not to nest layouts. – Aurify

Answer 4

So my fix for this issue turn out just to leverage the compound drawable feature of textview. I just trashed the button and used drawableRight to show the search icon.

Omnidirectional