Put buttons at bottom of screen with LinearLayout?
我有下面的代码,我怎样才能让3个按钮在底部?
    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="60dp"
        android:gravity="center"
        android:text="@string/observer"
        android:textAppearance="?android:attr/textAppearanceLarge"
        tools:context=".asdf"
        android:weight="1" />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >
        <Button
            android:id="@+id/button1"
            style="?android:attr/buttonStyleSmall"
            android:layout_width="145dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|center"
            android:text="1" />
        <Button
            android:id="@+id/button2"
            style="?android:attr/buttonStyleSmall"
            android:layout_width="145dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|center"
            android:text="2" />
        <Button
            android:id="@+id/button3"
            style="?android:attr/buttonStyleSmall"
            android:layout_width="145dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|center"
            android:text="3" />
    </LinearLayout>
You need to ensure four things:
LinearLayout has layout_height="match_parent"  LinearLayout has layout_weight="1" and layout_height="0dp"  TextView has layout_weight="0"  LinearLayout: android:gravity="center|bottom"   Notice that fill_parent does not mean "take up all available space".  However, if you use layout_height="0dp" with layout_weight="1" , then a view will take up all available space (Can't get proper layout with "fill_parent").  
Here is some code I quickly wrote up that uses two LinearLayouts in a similar fashion to your code.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/db1_root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/textView1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="@string/cow"
        android:layout_weight="0"
        android:textAppearance="?android:attr/textAppearanceLarge" />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dip"
        android:layout_weight="1"
        android:gravity="center|bottom"
        android:orientation="vertical" >
        <Button
            android:id="@+id/button1"
            style="?android:attr/buttonStyleSmall"
            android:layout_width="145dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|center"
            android:text="1" />
        <Button
            android:id="@+id/button2"
            style="?android:attr/buttonStyleSmall"
            android:layout_width="145dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|center"
            android:text="2" />
        <Button
            android:id="@+id/button3"
            style="?android:attr/buttonStyleSmall"
            android:layout_width="145dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|center"
            android:text="3" />
    </LinearLayout>
</LinearLayout>
The result looks like similar to this:

您可以使用RelativeLayout并将其与android:layout_alignParentBottom="true"的底部对齐android:layout_alignParentBottom="true" 
创建相对布局,并在该布局内用此线创建按钮
android:layout_alignParentBottom="true"
上一篇: 如何在UI底部的固定位置设置按钮?
