207

I'm trying to center an ImageView inside a LinearLayout horizontally and vertically, but I just can't do it. The main reason why I'm not using a RelativeLayout for that is because I need the layout_weight (my Activity consists of four columns that should be equally divided, and also responsive to different screen widths, each column having an ImageView centered and unstretched).

Here is my xml so far:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000"
    android:baselineAligned="false"
    android:gravity="center"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".Main" >

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1" >

        <ImageView
            android:id="@+id/imageButton_speak"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_speak" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1" >

        <ImageView
            android:id="@+id/imageButton_readtext"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_readtext" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1" >

        <ImageView
            android:id="@+id/imageButton_edit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_edit" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1" >

        <ImageView
            android:id="@+id/imageButton_config"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_config" />
    </LinearLayout>
</LinearLayout>
horta
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6 Answers6

485

android:gravity handles the alignment of its children,

android:layout_gravity handles the alignment of itself.

So use one of these.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000"
    android:baselineAligned="false"
    android:gravity="center"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".Main" >

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center" >

        <ImageView
            android:id="@+id/imageButton_speak"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_speak" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center" >

        <ImageView
            android:id="@+id/imageButton_readtext"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_readtext" />
    </LinearLayout>

    ...
</LinearLayout>

(Every node except leaf nodes should have android:gravity="center".)

or

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000"
    android:baselineAligned="false"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".Main" >

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1" >

        <ImageView
            android:id="@+id/imageButton_speak"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_speak" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1" >

        <ImageView
            android:id="@+id/imageButton_readtext"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:background="@drawable/image_bg"
            android:src="@drawable/ic_readtext" />
    </LinearLayout>

    ...
</LinearLayout>

(Every node except the root node should have android:layout_gravity="center".)

Naetmul
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    "android:layout_gravity takes care of itself." would amend to say layout gravity is used by the parent. – ataulm Jan 13 '17 at 09:38
49

android:layout_gravity is used for the layout itself

Use android:gravity="center" for children of your LinearLayout

So your code should be:

<LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:layout_weight="1" >
Andy
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Tarsem Singh
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13

I tried solutions mentioned here but It didn't help me. I mind the solution is layout_width have to use wrap_content as value.

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:layout_weight="1" >
ViTUu
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7

Here's some sample code. This worked for me.

<LinearLayout
    android:gravity="center"
    >
    <TextView
        android:layout_gravity="center"
        />
    <Button
        android:layout_gravity="center"
        />
</LinearLayout>

So you're designing the Linear Layout to place all its contents (TextView and Button) in its center, and then the TextView and Button are placed relative to the center of the Linear Layout.

user812786
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pcodex
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    simple. The 'gravity' attribute affects the content of a view. So in this case what's the content of the LinearLayout? A TextView and a Button. In effect you are instructing the Layout Manager to centralise any content of the Linear Layout. – pcodex Mar 27 '18 at 01:47
3

android:gravity can be used on a Layout to align its children.

android:layout_gravity can be used on any view to align itself in its parent.

NOTE: If self or children is not centering as expected, check if width/height is match_parent and change to something else

Gibolt
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2

If you are looking for an answer in java code,

LinearLayout linearLayout = new LinearLayout(context);
linearLayout.setGravity(Gravity.CENTER);
// add children
rahulrvp
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