page.title=Linear Layout parent.title=Hello, Views parent.link=index.html @jd:body

{@link android.widget.LinearLayout} is a {@link android.view.ViewGroup} that displays child {@link android.view.View} elements in a linear direction, either vertically or horizontally.

You should be careful about over-using the {@link android.widget.LinearLayout}. If you begin nesting multiple {@link android.widget.LinearLayout}s, you may want to consider using a {@link android.widget.RelativeLayout} instead.

  1. Start a new project named HelloLinearLayout.
  2. Open the res/layout/main.xml file and insert the following: 
    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

  <LinearLayout
      android:orientation="horizontal"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:layout_weight="1">
      <TextView
          android:text="red"
          android:gravity="center_horizontal"
          android:background="#aa0000"
          android:layout_width="wrap_content"
          android:layout_height="fill_parent"
          android:layout_weight="1"/>
      <TextView
          android:text="green"
          android:gravity="center_horizontal"
          android:background="#00aa00"
          android:layout_width="wrap_content"
          android:layout_height="fill_parent"
          android:layout_weight="1"/>
      <TextView
          android:text="blue"
          android:gravity="center_horizontal"
          android:background="#0000aa"
          android:layout_width="wrap_content"
          android:layout_height="fill_parent"
          android:layout_weight="1"/>
      <TextView
          android:text="yellow"
          android:gravity="center_horizontal"
          android:background="#aaaa00"
          android:layout_width="wrap_content"
          android:layout_height="fill_parent"
          android:layout_weight="1"/>
  </LinearLayout>
	
  <LinearLayout
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="1">
    <TextView
        android:text="row one"
        android:textSize="15pt"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>
    <TextView
        android:text="row two"
        android:textSize="15pt"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>
    <TextView
        android:text="row three"
        android:textSize="15pt"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>
    <TextView
        android:text="row four"
        android:textSize="15pt"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>
  </LinearLayout>

</LinearLayout>

    Carefully inspect this XML. There is a root {@link android.widget.LinearLayout} that defines its orientation to be vertical—all child {@link android.view.View}s (of which it has two) will be stacked vertically. The first child is another {@link android.widget.LinearLayout} that uses a horizontal orientation and the second child is a {@link android.widget.LinearLayout} that uses a vertical orientation. Each of these nested {@link android.widget.LinearLayout}s contain several {@link android.widget.TextView} elements, which are oriented with each other in the manner defined by their parent {@link android.widget.LinearLayout}.

  3. Now open HelloLinearLayout.java and be sure it loads the res/layout/main.xml layout in the {@link android.app.Activity#onCreate(Bundle) onCreate()} method:

    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

    The {@link android.app.Activity#setContentView(int)} method loads the layout file for the {@link android.app.Activity}, specified by the resource ID — R.layout.main refers to the res/layout/main.xml layout file.

  4. Run the application.

You should see the following:

Notice how the XML attributes define each View's behavior. Try experimenting with different values for android:layout_weight to see how the screen real estate is distributed based on the weight of each element. See the Common Layout Objects document for more about how {@link android.widget.LinearLayout} handles the android:layout_weight attribute.

References