Defining a percentage width for a LinearLayout? [duplicate]

Question

You have to set the weight property of your elements. Create three RelativeLayouts as children to your LinearLayout and set weights 0.15, 0.70, 0.15. Then add your buttons to the second RelativeLayout(the one with weight 0.70).

Like this:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:id="@+id/layoutContainer" android:orientation="horizontal">
    <RelativeLayout
        android:layout_width="0dip"
        android:layout_height="fill_parent"
        android:layout_weight="0.15">
    </RelativeLayout>
    <RelativeLayout
        android:layout_width="0dip"
        android:layout_height="fill_parent"
        android:layout_weight="0.7">
        
        <!-- This is the part that's 70% of the total width. I'm inserting a LinearLayout and buttons.-->   
            <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:orientation="vertical">
                
                <Button 
                    android:text="Button1"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content">
                </Button>
                <Button
                    android:text="Button2"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content">
                </Button>
                <Button
                    android:text="Button3"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content">
                </Button>
                
            </LinearLayout>
        <!-- 70% Width End-->
        
    </RelativeLayout>
    <RelativeLayout
        android:layout_width="0dip"
        android:layout_height="fill_parent"
        android:layout_weight="0.15">
    </RelativeLayout>
</LinearLayout>

Why are the weights 0.15, 0.7 and 0.15? Because the total weight is 1 and 0.7 is 70% of the total.

Result:

Edit: Thanks to @SimonVeloper for pointing out that the orientation should be horizontal and not vertical and to @Andrew for pointing out that weights can be decimals instead of integers.

i know another solution, that work with weight:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent" 
              android:weightSum="10" 
              android:gravity="center_horizontal">

    <LinearLayout
            android:orientation="vertical"
            android:layout_width="wrap_content"
            android:layout_height="match_parent" 
            android:layout_weight="7">
    </LinearLayout>
</LinearLayout>

Hope this can help

<LinearLayout android:layout_width="fill_parent"
    android:layout_height="fill_parent" android:orientation="horizontal">

    <LinearLayout android:layout_width="0dip"
        android:layout_height="wrap_content" android:orientation="horizontal"
        android:id="@+id/linearLayout_dummy1" android:layout_weight=".15">
    </LinearLayout>


    <LinearLayout android:layout_height="wrap_content"
        android:id="@+id/linearLayout1" android:orientation="vertical"
        android:layout_width="0dip" android:layout_weight=".7">
        <Button android:text="Button" android:id="@+id/button1"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:layout_gravity="center">
        </Button>
        <Button android:layout_width="wrap_content" android:id="@+id/button2"
            android:layout_height="wrap_content" android:text="Button"
            android:layout_gravity="center"></Button>
        <Button android:layout_width="wrap_content" android:id="@+id/button3"
            android:layout_height="wrap_content" android:text="Button"
            android:layout_gravity="center"></Button>
    </LinearLayout>

    <LinearLayout android:layout_width="0dip"
        android:layout_height="wrap_content" android:orientation="horizontal"
        android:id="@+id/linearLayout_dummy2" android:layout_weight=".15">
    </LinearLayout>

</LinearLayout>

(1) Set layout_width to "0dip" (2) Set the layout_height to .xx (% you want)

I think Emiam's approach is right. But also agree with Simon Veloper (one of commentators of Emiam's answer) : When we need the buttons in 70% of width, we should use horizontal orientation for Linearlayout and set width of each Relativelayout to 0dip and their weight as specified So I suggest this version :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent" android:layout_height="fill_parent"
        android:id="@+id/layoutContainer" android:orientation="horizontal">
    <RelativeLayout
            android:layout_width="0dip"
            android:layout_height="fill_parent"
            android:layout_weight="3">
    </RelativeLayout>
    <RelativeLayout
            android:layout_width="0dip"
            android:layout_height="fill_parent"
            android:layout_weight="14">

            //This is where you add buttons. You can make them "fill_parent".
    </RelativeLayout>
    <RelativeLayout
            android:layout_width="0dip"
            android:layout_height="fill_parent"
            android:layout_weight="3">
    </RelativeLayout>
</LinearLayout>

As a latest update to android in 2015, Google has included percent support library

com.android.support:percent:23.1.0

You can refer to this site for example of using it

https://github.com/JulienGenoud/android-percent-support-lib-sample

Gradle:

dependencies {
    compile 'com.android.support:percent:22.2.0'
}

In the layout:

<android.support.percent.PercentRelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <View
        android:id="@+id/top_left"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_alignParentTop="true"
        android:background="#ff44aacc"
        app:layout_heightPercent="20%"
        app:layout_widthPercent="70%" />

    <View
        android:id="@+id/top_right"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_alignParentTop="true"
        android:layout_toRightOf="@+id/top_left"
        android:background="#ffe40000"
        app:layout_heightPercent="20%"
        app:layout_widthPercent="30%" />


    <View
        android:id="@+id/bottom"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_below="@+id/top_left"
        android:background="#ff00ff22"
        app:layout_heightPercent="80%" />
</android.support.percent.PercentRelativeLayout>

Use new percentage support library

compile 'com.android.support:percent:24.0.0'

See below example

<android.support.percent.PercentRelativeLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
     <ImageView
         app:layout_widthPercent="50%"
         app:layout_heightPercent="50%"
         app:layout_marginTopPercent="25%"
         app:layout_marginLeftPercent="25%"/>
 </android.support.percent.PercentRelativeLayout>

For More Info Tutorial1 Tutorial2 Tutorial3