Dodawanie przycisku pod listview na androida

Question

Więc próbowałem dodać przycisk pod listview w Androidzie, problem polega na tym, że przycisk nie pojawia się.

<?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 jest przestarzałe. Proponuję zamiast tego użyć 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> 

Chciałbym również zasugerować czytania przez developer docs na układach dobrego wprowadzenia.

Answer 2

Istnieje przykład takiego układu w przykładach "Dema API". Następujące strony odwołują się do próbek:

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

szukać LinearLayout9.java plików, i odpowiadająca jej linear_layout9.xml plik układu. Dla wygody, mam wklejony je tutaj:

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>