Agregar un botón debajo de una vista de lista en android

Question

Por lo que he estado tratando de agregar un botón debajo de una vista de lista en Android, el problema es que el botón no aparece.

<?xml version="1.0" encoding="utf-8"?> 
<AbsoluteLayout 
    android:id="@+id/widget0" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    xmlns:android="http://schemas.android.com/apk/res/android"> 

    <ListView 
     android:id="@+id/messagelist" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_x="0px" 
     android:layout_y="0px"> 
    </ListView> 
    <Button 
     android:id="@+id/addbutton" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Button" 
     android:layout_x="0px" 
     android:layout_y="379px"> 
    </Button> 
</AbsoluteLayout> 

Answer 1

AbsoluteLayout está deshabilitado. Yo sugeriría que en vez de utilizar un LinearLayout:

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
    android:id="@+id/widget0" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    xmlns:android="http://schemas.android.com/apk/res/android"> 

    <ListView 
     android:id="@+id/messagelist" 
     android:layout_width="wrap_content" 
     android:layout_height="0dp" 
     android:layout_weight="1"> 
    </ListView> 
    <Button 
     android:id="@+id/addbutton" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Button"> 
    </Button> 
</LinearLayout> 

También me gustaría sugerir la lectura a través de la developer docs en los diseños para una buena introducción.

Answer 2

Hay un ejemplo de dicho diseño en la muestra "Demos de API". La siguiente página enlaza a las muestras:

http://developer.android.com/resources/samples/index.html

buscar la LinearLayout9.java archivo, y su correspondiente archivo de diseño linear_layout9.xml. Para mayor comodidad, los he pegado aquí:

LinearLayout9.java:

/* 
* Copyright (C) 2007 The Android Open Source Project 
* 
* Licensed under the Apache License, Version 2.0 (the "License"); 
* you may not use this file except in compliance with the License. 
* You may obtain a copy of the License at 
* 
*  http://www.apache.org/licenses/LICENSE-2.0 
* 
* Unless required by applicable law or agreed to in writing, software 
* distributed under the License is distributed on an "AS IS" BASIS, 
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
* See the License for the specific language governing permissions and 
* limitations under the License. 
*/ 

package com.example.android.apis.view; 

import com.example.android.apis.R; 

import android.app.Activity; 
import android.os.Bundle; 
import android.widget.ListView; 
import android.widget.ArrayAdapter; 

/** 
* Demonstrates how the layout_weight attribute can shrink an element too big 
* to fit on screen. 
*/ 
public class LinearLayout9 extends Activity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.linear_layout_9); 
     ListView list = (ListView) findViewById(R.id.list); 
     list.setAdapter(new ArrayAdapter<String>(this, 
       android.R.layout.simple_list_item_1, AutoComplete1.COUNTRIES)); 
    } 

} 

linear_layout9.xml:

<?xml version="1.0" encoding="utf-8"?> 
<!-- Copyright (C) 2007 The Android Open Source Project 

    Licensed under the Apache License, Version 2.0 (the "License"); 
    you may not use this file except in compliance with the License. 
    You may obtain a copy of the License at 

      http://www.apache.org/licenses/LICENSE-2.0 

    Unless required by applicable law or agreed to in writing, software 
    distributed under the License is distributed on an "AS IS" BASIS, 
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
    See the License for the specific language governing permissions and 
    limitations under the License. 
--> 

<!-- 
    Demonstrates a simple linear layout. The layout fills the screen, with the 
    children stacked from the top. 
    --> 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <ListView android:id="@+id/list" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_weight="1.0" /> 

    <Button 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:text="@string/linear_layout_9_button" /> 

</LinearLayout>