Android:什么时候使用layout_margin，什么时候使用weightSum? [英] Android: When to use layout_margin, when to use weightSum?

问题描述

我正在尝试在Android应用上实现以下布局:

I am trying to achieve the following layout on my Android app:

如您所见，我希望中央登录框占用大约70％的宽度.我相信基本上有两种方法可以实现这一目标:

As you can see I want a central login box taking about 70% of the width. I believe there are basically two approaches to achieve this:

1..为登录框创建线性或相对布局，并在左右两侧添加layoutMargin.

1. Create a Linear or Relative layout for the login box, and add layoutMargin both on the left and right sides.

2..创建一个带有weightSum ="1"的包装器LinearLayout，然后将其中的RelativeLayout放在layout_width ="0dp"和layout_weight ="0.7"的内部.

2. Create a wrapper LinearLayout with weightSum="1", and then place the RelativeLayout inside it with layout_width="0dp" and layout_weight="0.7".

使用第一种方法，XML如下所示:

Using the first approach the XML would look like this:

<LinearLayout 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:orientation="vertical">

    <ImageView
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"        
        android:src="@drawable/logo"
        android:contentDescription="@string/logo"  
         />

    <LinearLayout
        android:layout_width="match_parent"         
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:background="#999999"
        android:gravity="center"
        android:layout_margin="30dp"
         >
        <EditText
            android:layout_width="fill_parent"           
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:layout_marginLeft="20dp"
            android:layout_marginRight="20dp"
            android:hint="@string/email" />
        <EditText
            android:layout_width="fill_parent"            
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:layout_marginRight="20dp"
            android:hint="@string/password" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"  
            android:text="@string/login"/>


    </LinearLayout>     


</LinearLayout>

第二种方法是在当前方法的顶部添加一个包装LinearLine，重量为weightsum ="1"，内部布局将获得layout_weight ="0.7"属性.

The second approach would just have a wrapper LinearLayout on top of the current one, with weightSum="1", and the internal layout would get a layout_weight="0.7" attribute.

您认为哪种方法最好?预先感谢.

Which one do you think is the best approach? Thanks in advance.

推荐答案

一种相当简单的方法是在相对布局内使用线性布局.然后使用layout_centerInParent并将其设置为"true".完成此操作后，您可以将余量设置为您想要的余量(我使用了30 dp).这是一个示例:

A rather simple way would be use a linear layout inside a relative layout. Then use layout_centerInParent and set it to "true". Once that is done you can set your margin to what ever you would like (I used 30 dp). Here is an example:

<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" >

<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:layout_margin="30dp"
    android:orientation="vertical"
    android:weightSum="50" >

    <EditText
    android:id="@+id/editText1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:inputType="textEmailAddress" >

    <requestFocus />
</EditText>

<EditText
    android:id="@+id/editText2"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/editText1"
    android:layout_centerHorizontal="true"
    android:inputType="numberPassword" />

<Button
    android:id="@+id/button1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/editText2"
    android:layout_centerHorizontal="true"
    android:text="Button" />
</LinearLayout>

</RelativeLayout>

当然，如果您希望登录框的宽度恰好是屏幕宽度的70％，则可以通过编程方式进行.

Of course, if you wanted the width of the log in box to be exactly 70 percent of the width of the screen, you could do it programmatically.

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