Four basic layouts of android--

1. Linear layout

<LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "Horizontal" <!--horizontal for horizontal arrangement vertical vertical arrangement--Android:layout_width= "Match_parent"Android:layout_height= "Match_parent">    <ButtonAndroid:id= "@+id/button1"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"Android:text= "Button1" />    <ButtonAndroid:id= "@+id/button2"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"Android:text= "Button2" />    <ButtonAndroid:id= "@+id/button3"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"Android:text= "Button3" /></LinearLayout>

Select alignment by Layout_gravity

<LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "Horizontal"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent">    <ButtonAndroid:id= "@+id/button1"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"android:layout_gravity= "Top"Android:text= "Button1" />    <ButtonAndroid:id= "@+id/button2"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"android:layout_gravity= "Center_vertical"Android:text= "Button2" />    <ButtonAndroid:id= "@+id/button3"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"android:layout_gravity= "Bottom"Android:text= "Button3" /></LinearLayout>

As shown

Layout_width to set the scale of the screen the system adds all the controls under LinearLayout to the total value and then the layout_width of each control is the scale.

<LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "Horizontal"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent">    <EditTextAndroid:id= "@+id/input_message"Android:layout_width= "0DP"Android:layout_height= "Wrap_content"Android:layout_weight= "3"Android:hint= "Type Something"        />    <ButtonAndroid:id= "@+id/send"Android:layout_width= "0DP"Android:layout_height= "Wrap_content"Android:layout_weight= "2"Android:text= "Send"        /></LinearLayout>

As shown

If the button's layout_width is set to Wrap_content, EditText's layout_weight is set to 1 for the following display

2. Relative layout

　　

Four basic layouts of android--