Question

所以我一直试图在android的listview下面添加一个按钮，问题是该按钮没有出现。

<?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

不推荐使用AbsoluteLayout。我建议您使用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>

我还建议阅读布局上的developer docs以获得一个很好的介绍。

Answer 2

“API Demos”示例中有一个这样的布局示例。以下页面链接到示例：

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

查找文件LinearLayout9.java及其对应的布局文件linear_layout9.xml。为方便起见，我在这里粘贴了它们：

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>

在android上的listview下面添加一个按钮

2 个答案: