如何使用带有可扩展列表的 xml 布局？答案

【问题标题】：How to use xml layout with expandable list?如何使用带有可扩展列表的 xml 布局？
【发布时间】：2011-12-15 03:58:23
【问题描述】：

您好，我有这个可扩展列表，当我尝试使用此代码将其连接到 xml 文件时出现错误。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.directions);
    // Set up our adapter
    mAdapter = new MyExpandableListAdapter();
    setListAdapter(mAdapter);
    registerForContextMenu(getExpandableListView());
}

使用此代码，当我将按钮重定向到整个 java 文件时，我会强制关闭。（查看下面的完整代码）原木猫这样说：

10-25 17:37:39.512: 错误/AndroidRuntime(547): java.lang.RuntimeException：无法启动活动组件信息{com.sammy.umass/com.sammy.umass.DirectionsScreenActivity}： java.lang.RuntimeException: 你的内容必须有一个 id属性为'android.R.id.list'的ExpandableListView

我只需要删除标题栏，添加背景图像并基本美化它。

完整代码：

package com.sammy.umass;

import android.app.ExpandableListActivity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Gravity;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ExpandableListView.ExpandableListContextMenuInfo;


public class DirectionsScreenActivity extends ExpandableListActivity {
ExpandableListAdapter mAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.directions);
    // Set up our adapter
    mAdapter = new MyExpandableListAdapter();
    setListAdapter(mAdapter);
    registerForContextMenu(getExpandableListView());
}

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    //menu.setHeaderTitle("Sample menu");
    //menu.add(0, 0, 0, R.string.expandable_list_sample_action);
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo();

    String title = ((TextView) info.targetView).getText().toString();

    int type = ExpandableListView.getPackedPositionType(info.packedPosition);
    if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
        int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); 
        int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition); 
        Toast.makeText(this, title + ": Child " + childPos + " clicked in group " + groupPos,
                Toast.LENGTH_SHORT).show();
        return true;
    } else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {
        int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); 
        Toast.makeText(this, title + ": Group " + groupPos + " clicked", Toast.LENGTH_SHORT).show();
        return true;
    }

    return false;
}

/**
 * A simple adapter which maintains an ArrayList of photo resource Ids. 
 * Each photo is displayed as an image. This adapter supports clearing the
 * list of photos and adding a new photo.
 *
 */
public class MyExpandableListAdapter extends BaseExpandableListAdapter {
    // Sample data set.  children[i] contains the children (String[]) for groups[i].
    private String[] groups = { "   Academic Buildings", "   Residential Buildings", "   Dining Commons", "   All Buildings A-Z" };
    private String[][] children = {
            //Academic Buildings
            { "Agricultural Engineering Bldg", "Army ROTC Bldg", "Arnold House", "(Studio) Arts Building" },
            //Residence Halls
            { "Baker Hall", "Brett Hall", "Brooks Hall", "Brown Hall","Butterfield Hall","Cance Hall","Cashin Hall","Chadboourne Hall",
                "Coolidge Hall","Crabtree Hall","Crampton Hall","Dickinson Hall","Dwight Hall","Emerson Hall","Field Hall",
                "Gorman Hall","Grayson Hall","Greenough Hall","Hamlin Hall","James Hall","John Adams Hall","John Quincy Adams Hall",
                "Johnson Hall","Kennedy Hall","Knowlton Hall","Leach Hall","Lewis Hall","Lincoln Apts","Mackimmie Hall","Mary Lyon Hall",
                "McNamara Hall","Melville Hall","Moore Hall","North Residence A","North Residence B","North Residence C","North Residence D",
                "North Village Apts","Patterson Hall","Pierpont Hall","Prince Hall","Thatcher Hall","Thoreau Hall","Van Meter Hall",
                "Washington Hall","Webster Hall","Wheeler Hall"},
            //Dining Commons
            { "Berkshire", "Franklin","Hampden","Hampshire","Worcester" },
            { "Agricultural Engineering Bldg", "Army ROTC Bldg", "Arnold House", "(Studio) Arts Building" }
    };

    public Object getChild(int groupPosition, int childPosition) {
        return children[groupPosition][childPosition];
    }

    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    public int getChildrenCount(int groupPosition) {
        return children[groupPosition].length;
    }

    public TextView getGenericView() {
        // Layout parameters for the ExpandableListView
        AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT, 64);

        TextView textView = new TextView(DirectionsScreenActivity.this);
        textView.setLayoutParams(lp);
        // Center the text vertically
        textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
        // Set the text starting position
        textView.setPadding(36, 0, 0, 0);
        return textView;
    }

    public View getChildView(final int groupPosition,final int childPosition, boolean isLastChild,
            View convertView, ViewGroup parent) {
        TextView textView = getGenericView();
        textView.setText(getChild(groupPosition, childPosition).toString());
        textView.setOnClickListener(new View.OnClickListener(){
          public void onClick(View view){
            Uri uriToOpen = getUriForView(groupPosition, childPosition);
            Intent i = new Intent(Intent.ACTION_VIEW, uriToOpen);
            startActivity(i);
          }

        private Uri getUriForView(int groupPosition, int childPosition) 
        {
            //Academic Builds
            //Residence Halls
            if(groupPosition == 1 && childPosition == 0)
                return Uri.parse("google.navigation:q=160+Clark+Hill+Road+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 1)
                return Uri.parse("google.navigation:q=151+Infirmary+Way+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 2)
                return Uri.parse("google.navigation:q=160+Infirmary+Way+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 3)
                return Uri.parse("google.navigation:q=92+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 4)
                return Uri.parse("google.navigation:q=171+Infirmary+Way+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 5)
                return Uri.parse("google.navigation:q=191+Fearing+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 6)
                return Uri.parse("google.navigation:q=112+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 7)
                return Uri.parse("google.navigation:q=110+Orchard+Hill+Drive+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 8)
                return Uri.parse("google.navigation:q=630+Massachusetts+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 9)
                return Uri.parse("google.navigation:q=17+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 10)
                return Uri.parse("google.navigation:q=256+Sunset+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 11)
                return Uri.parse("google.navigation:q=151+Orchard+Hill+Drive+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 12)
                return Uri.parse("google.navigation:q=41+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 13)
                return Uri.parse("google.navigation:q=151+Southwest+Circle+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 14)
                return Uri.parse("google.navigation:q=171+Orchard+Hill+Drive+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 15)
                return Uri.parse("google.navigation:q=90+Butterfield+Terrace+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 16)
                return Uri.parse("google.navigation:q=161+Orchard+Hill+Drive+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 17)
                return Uri.parse("google.navigation:q=120+Orchard+Hill+Drive+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 18)
                return Uri.parse("google.navigation:q=739+North+Pleasant+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 19)
                return Uri.parse("google.navigation:q=660+Massachusetts+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 20)
                return Uri.parse("google.navigation:q=161+Fearing+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 21)
                return Uri.parse("google.navigation:q=171+Fearing+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 22)
                return Uri.parse("google.navigation:q=380+Thatcher+Road+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 23)
                return Uri.parse("google.navigation:q=42.38421349589919+-72.52963542938232"+"&mode=w");
            if(groupPosition == 1 && childPosition == 24)
                return Uri.parse("google.navigation:q=691+North+Pleasant+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 25)
                return Uri.parse("google.navigation:q=21+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 26)
                return Uri.parse("google.navigation:q=340+Thatcher+Road+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 27)
                return Uri.parse("google.navigation:q=341+Lincoln+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 28)
                return Uri.parse("google.navigation:q=230+Sunset+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 29)
                return Uri.parse("google.navigation:q=43+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 30)
                return Uri.parse("google.navigation:q=102+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 31)
                return Uri.parse("google.navigation:q=650+Massachusetts+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 32)
                return Uri.parse("google.navigation:q=111+Southwest+Circle+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 33)
                return Uri.parse("google.navigation:q=56+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 34)
                return Uri.parse("google.navigation:q=58+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 35)
                return Uri.parse("google.navigation:q=54+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 36)
                return Uri.parse("google.navigation:q=52+Eastman+Lane+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 37)
                return Uri.parse("google.navigation:q=990+North+Pleasant+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 38)
                return Uri.parse("google.navigation:q=204+Sunset+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 39)
                return Uri.parse("google.navigation:q=201+Fearing+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 40)
                return Uri.parse("google.navigation:q=286+Sunset+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 41)
                return Uri.parse("google.navigation:q=300+Thatcher+Road+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 42)
                return Uri.parse("google.navigation:q=640+Massachusetts+Avenue+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 43)
                return Uri.parse("google.navigation:q=180+Clark+Hil+Road+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 44)
                return Uri.parse("google.navigation:q=181+Fearing+Street+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 45)
                return Uri.parse("google.navigation:q=141+Orchard+Hill+Drive+Amherst+MA+01003"+"&mode=w");
            if(groupPosition == 1 && childPosition == 46)
                return Uri.parse("google.navigation:q=171+Infirmary+Way+Amherst+MA+01003"+"&mode=w");
            //Dining Commons
            //All Buildings
            return null;
        }
        });

        return textView;
    }

    public Object getGroup(int groupPosition) {
        return groups[groupPosition];
    }

    public int getGroupCount() {
        return groups.length;
    }

    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
            ViewGroup parent) {
        TextView textView = getGenericView();
        textView.setText(getGroup(groupPosition).toString());
        return textView;
    }

    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    public boolean hasStableIds() {
        return true;
    }



}
}

XML 代码

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

【问题讨论】：

标签： android xml expandablelistview

【解决方案1】：

当使用 ExpandableListAdapter 时，提供的 XML 布局需要有一个 ExpandableListView 元素，其中 id 属性设置为 android.R.id.list。您的问题出在您的方向.xml 布局中。确保在您的directions.xml 中有一个ExpandableListView 元素，并且它的id 属性设置为andoird.R.id.list。您需要在您的directoions.xml 中执行此操作：

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

</LinearLayout>

【讨论】：

为规范目的而编辑。使用了@LalitPoptani 发布的代码，并为他投了赞成票。
我会把这段代码放在哪里？ android:background="@color/white" 在线性布局或可扩展列表视图中？我已经在字符串中为它赋值了
这是一个单独的问题，所以请在新问题中提出。也就是说，为什么不自己尝试一下呢？经验是最好的老师 :) 我总是觉得尝试不同的事情很有趣，看看什么有效，什么无效。
哈哈我做过实验！生病继续尝试，如果我不明白，我会问另一个问题。再次感谢！
@squid267 这就是真正的开发者/黑客的精神！恭喜！

【解决方案2】：

您必须在 xml 文件中为 ExpandableListView 添加 android 内置 id，如下所示，并删除您自己使用 android:id="@+id/anyname" 声明的 id

       <ExpandableListView 
        android:id="@android:id/list"
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content">
        </ExpandableListView>

【讨论】：