Android - RelativeLayout布局

RelativeLayout布局

本文地址:http://blog.csdn.net/caroline_wendy

RelativeLayout是一种相对布局方式，是根据属性进行对齐；

A Layout where the positions of the children can be described in relation to each other or to the parent.

在布局中，子控件的位置根据相互之间的关系进行描述。

Note that you cannot have a circular dependency between the size of the RelativeLayout and the position of its children.

子控件之间不能存在循环依赖。

Note: In platform version 17 and lower, RelativeLayout was affected by a measurement bug that could 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 would silently work anyway as RelativeLayout would 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

android:layout_toStartOf="@+id/buttonTweet” //表是在某个控件的前对齐，如果不知道，就图形界面拖动

<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>