android 布局中 layout_gravity、gravity、orientation、layout_weight

下面以一个简单例子来说明这 4个参数：

<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
                           android:layout_height = "200dp"
                           android:layout_width = "200dp"
                           android:background = "#AABBCC"
                           android:orientation= "horizontal"
                           android:layout_gravity= "center" >
                           < TextView android:text = "ONE"
                                               android:background = "#aa0000"
                                               android:layout_height = "wrap_content"
                                               android:layout_width = "wrap_content"
                                               android:layout_margin = "1dp" />
                            < TextView android:text = "TWO"
                                               android:background = "#aa0000"
                                               android:layout_height = "wrap_content"
                                               android:layout_width = "wrap_content"
                                               android:layout_margin = "1dp" />
</ LinearLayout >

说明：对LinearLayout 中的参数android:layout_gravity 来说，其意义是指定本布局相对于父布局的重力方向，由于该布局的已经是根布局，其父布局是整个屏幕，那么该参数设置的是相对于屏幕的位置，可以换不同的参数top|bottom|left|right 等等参数来试验。
现在增加参数 android:gravity = "bottom|right" 完整 XML 如下，看看效果

<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
                      android:layout_height = "200dp"
                      android:layout_width = "200dp"
                      android:background = "#AABBCC"
                      android:orientation="horizontal"
                      android:layout_gravity= "center"
                      android:gravity = "bottom|right " >
                      < TextView android:text = "ONE"
                                     android:background = "#aa0000"
                                     android:layout_height = "wrap_content"
                                     android:layout_width = "wrap_content"
                                     android:layout_margin = "1dp" />
                      < TextView android:text = "TWO"
                                     android:background = "#aa0000"
                                     android:layout_height = "wrap_content"
                                     android:layout_width = "wrap_content"
                                     android:layout_margin = "1dp" />
</ LinearLayout >

通过改变android:gravity 参数的值可以看到实际效果。


参数 android:orientation= " horizontal " 决定了每个子元素各占一列，如果
参数 android:orientation= " vertical " ， 则每个子元素各占一行，也就是从上到下排列了。


对于 LinearLayout 布局的子元素，给每个子元素加上参数 android:layout_weight

<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
                      android:layout_height = "200dp"
                      android:layout_width = "200dp"
                      android:background = "#AABBCC"
                      android:layout_gravity = "center"
                      android:gravity = "bottom|right"
                      android:orientation = "horizontal" >
                      < TextView android:text = "ONE"
                                     android:background = "#aa0000"
                                     android:layout_height = "wrap_content"
                                     android:layout_width = "wrap_content"
                                     android:layout_margin = "1dp"
                                     android:layout_weight = "1" />
                      < TextView android:text = "TWO"
                                     android:background = "#aa0000"
                                     android:layout_height = "wrap_content"
                                     android:layout_width = "wrap_content"
                                     android:layout_margin = "1dp"
                                     android:layout_weight = "2" />
</ LinearLayout >

Text 为ONE 的权重为1 ，但明显占的宽度比TWO 的小，百思不得其解，后来得知，如果把TextView 的参数android:layout_width = "wrap_content" 全部修改为 android:layout_width = "fill_parent", 则 ok ，代码如下

<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
                      android:layout_height = "200dp"
                      android:layout_width = "200dp"
                      android:background = "#AABBCC"
                      android:layout_gravity = "center"
                      android:gravity = "bottom|right"
                      android:orientation = "horizontal" >
                      < TextView android:text = "ONE"
                                     android:background = "#aa0000"
                                     android:layout_height = "wrap_content"
                                     android:layout_width = " fill_parent "
                                     android:layout_margin = "1dp"
                                     android:layout_weight = "1" />
                      < TextView android:text = "TWO"
                                     android:background = "#aa0000"
                                     android:layout_height = "wrap_content"
                                     android:layout_width = " fill_parent "
                                     android:layout_margin = "1dp"
                                     android:layout_weight = "2" />
</ LinearLayout >

android 布局中 layout_gravity、gravity、orientation、layout_weight,布布扣,bubuko.com

android 布局中 layout_gravity、gravity、orientation、layout_weight

原文：http://blog.csdn.net/laijunpeng/article/details/22689869