Android and android Official Website

Android and android Official Website
RelativeLayout Layout

Address: http://blog.csdn.net/caroline_wendy

RelativeLayoutIs A relative Layout method, Alignment Based on attributes; A Layout where the positions of the children can be described in relation to each other or to the parent. in the layout, the position of the child control is described based on the relationship between them. Note that you cannot have a circular dependency between the size of the RelativeLayout and the position of its children. circular dependencies cannot exist between child controls.
Note:In platform version 17 and lower, RelativeLayout was affected by a measurement bug that cocould cause child views to be measured with incorrect MeasureSpec values. this was triggered when a RelativeLayout container was placed in a scrolling container, such as a ScrollView or HorizontalScrollView. if a custom view not equipped to properly measure with the MeasureSpec mode UNSPECIFIED was placed in a RelativeLayout, this wowould silently work anyway as RelativeLayout wocould pass a very large AT_MOST MeasureSpec instead. this behavior has been preserved for apps that set android: targetSdkVersion = "17" or older in their manifest's uses-sdk tag for compatibility. apps targeting SDK version 18 or newer will receive the correct behavior

Attribute name	Description
Android: layout_below	Placed under the specified component
Android: layout_toLeftOf	Placed on the left of the specified component
Android: layout_toRightOf	Placed on the right of the specified component
Android: layout_alignTop	Alignment with specified components as reference
Android: layout_algnBottom	Bottom alignment with specified component as reference
Android: layout_alignLeft	Align left with specified components as reference
Android: layout_alignRight	To specify Components

 
Android: layout_toStartOf = "@ + id/buttonTweet" // The table is aligned before a control. If you do not know it, drag it to the graphic interface.

<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:paddingBottom="@dimen/activity_vertical_margin"    tools:context=".StatusActivity">    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/button_tweet"        android:id="@+id/buttonTweet"        android:layout_alignParentEnd="true"/>    <EditText        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:inputType="textMultiLine"        android:ems="10"        android:id="@+id/editText"        android:layout_alignParentBottom="true"        android:layout_alignParentStart="true"        android:hint="@string/hint_status"        android:layout_toStartOf="@+id/buttonTweet"/>    <TextView        android:id="@+id/textCount"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignEnd="@id/buttonTweet"        android:layout_below="@id/buttonTweet"        android:text="140"        android:textAppearance="?android:textAppearanceSmall"/></RelativeLayout>