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ANDROID-带有类别的自定义列表视图

android listview

ANDROID-带有类别的自定义列表视图,android,listview,android-listview,Android,Listview,Android Listview,我将遵循该教程： 我有以下代码： 。/layout/target_item.xml <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="48dp" android

我将遵循该教程：

我有以下代码：

。/layout/target_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="48dp"
    android:background="#F3F3F3">

     <!-- icon -->
     <ImageView
         android:id="@+id/item_icon"
         android:layout_width="32dp"
         android:layout_height="32dp"
         android:layout_alignParentLeft="true"
         android:layout_marginLeft="8dp"
         android:layout_marginRight="8dp"
         android:layout_marginTop="8dp"
         android:src="@drawable/ic_action_help"
         />

    <!-- title -->
    <TextView
         android:id="@+id/item_title"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_toRightOf="@+id/item_icon"
         android:layout_alignBaseline="@+id/item_counter"
         android:textSize="18dp" />

        <!-- counter -->
        <TextView
            android:id="@+id/item_counter"
            android:layout_width="50dp"
            android:layout_height="32dp"
            android:layout_alignParentRight="true"
            android:layout_marginRight="8dp"
            android:layout_marginTop="8dp"
            android:background="@drawable/rectangle"
            android:gravity="center"
            android:textColor="#FFFFFF"
            android:textSize="12sp"
            android:textStyle="bold" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="30dp"

    android:background="#5490CC">

    <!-- title -->

    <TextView
        android:id="@+id/header"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="4dp"
        android:layout_marginLeft="12dp"
        android:gravity="center_vertical"
        android:textColor="@color/blanco"
        android:textSize="16dp"
        android:textStyle="bold" />

    <!--  divider -->
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="1dp"
        android:layout_alignParentBottom="true"
        android:background="#DADADC" ></View>

</RelativeLayout>

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

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

</LinearLayout>

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

    <ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
</ListView>

</LinearLayout>
src/../MyAdapter.java

public class Model{

    private int icon;
    private String title;
    private String counter;

    private boolean isGroupHeader = false;

    public Model(String title) {
        this(-1,title,null);
        isGroupHeader = true;
    }
    public Model(int icon, String title, String counter) {
        super();
        this.icon = icon;
        this.title = title;
        this.counter = counter;
    }
    public int getIcon() {
        return icon;
    }
    public void setIcon(int icon) {
        this.icon = icon;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getCounter() {
        return counter;
    }
    public void setCounter(String counter) {
        this.counter = counter;
    }
    public boolean isGroupHeader() {
        return isGroupHeader;
    }
    public void setGroupHeader(boolean isGroupHeader) {
        this.isGroupHeader = isGroupHeader;
    }
}

public class MyAdapter extends ArrayAdapter<Model> {

    private final Context context;
    private final ArrayList<Model> modelsArrayList;

    public MyAdapter(Context context, ArrayList<Model> modelsArrayList) {

        super(context, R.layout.target_item, modelsArrayList);

        this.context = context;
        this.modelsArrayList = modelsArrayList;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        // 1. Create inflater 
        LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        // 2. Get rowView from inflater

        View rowView = null;
        if(!modelsArrayList.get(position).isGroupHeader()){
            rowView = inflater.inflate(R.layout.target_item, parent, false);

            // 3. Get icon,title & counter views from the rowView
            ImageView imgView = (ImageView) rowView.findViewById(R.id.item_icon); 
            TextView titleView = (TextView) rowView.findViewById(R.id.item_title);
            TextView counterView = (TextView) rowView.findViewById(R.id.item_counter);

            // 4. Set the text for textView 
            imgView.setImageResource(modelsArrayList.get(position).getIcon());
            titleView.setText(modelsArrayList.get(position).getTitle());
            counterView.setText(modelsArrayList.get(position).getCounter());
        }`enter code here`
        else{
                rowView = inflater.inflate(R.layout.group_header_item, parent, false);
                TextView titleView = (TextView) rowView.findViewById(R.id.header);
                titleView.setText(modelsArrayList.get(position).getTitle());
        }

        // 5. retrn rowView
        return rowView;
    }
}

public class MainActivity extends ListActivity {

    public void onCreate(Bundle b) {
        super.onCreate(b);

 MyAdapter adapter = new MyAdapter(this, generateData());

   setListAdapter(adapter);
    }

private ArrayList<Model> generateData(){
        ArrayList<Model> models = new ArrayList<Model>();
        models.add(new Model("group1"));
        models.add(new Model(R.drawable.ic_action_help,"item 1","1"));
        models.add(new Model(R.drawable.ic_action_search,"item2","25"));
 return models;
    }
}

public class MainActivity extends ListActivity {

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        // extending Activity
        setContentView(R.layout.activity_main);

        // 1. pass context and data to the custom adapter
        MyAdapter adapter = new MyAdapter(this, generateData());

        //  Get ListView from activity_main.xml
        ListView list = (ListView) findViewById(android.R.id.list);


        // 3. setListAdapter
        list.setAdapter(adapter); //extending Activity
        //setListAdapter(adapter);
    }

//......
我试过了，但没有成功，我不知道我怎么能做到

更新

public class MainActivity extends ListActivity {

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
setContentView(R.layout.activity_main);

 ListView listView = (ListView) findViewById(R.id.list);

//.......
我用名为R.id.list的ListView添加了activity_main.xml

活动\u main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="48dp"
    android:background="#F3F3F3">

     <!-- icon -->
     <ImageView
         android:id="@+id/item_icon"
         android:layout_width="32dp"
         android:layout_height="32dp"
         android:layout_alignParentLeft="true"
         android:layout_marginLeft="8dp"
         android:layout_marginRight="8dp"
         android:layout_marginTop="8dp"
         android:src="@drawable/ic_action_help"
         />

    <!-- title -->
    <TextView
         android:id="@+id/item_title"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_toRightOf="@+id/item_icon"
         android:layout_alignBaseline="@+id/item_counter"
         android:textSize="18dp" />

        <!-- counter -->
        <TextView
            android:id="@+id/item_counter"
            android:layout_width="50dp"
            android:layout_height="32dp"
            android:layout_alignParentRight="true"
            android:layout_marginRight="8dp"
            android:layout_marginTop="8dp"
            android:background="@drawable/rectangle"
            android:gravity="center"
            android:textColor="#FFFFFF"
            android:textSize="12sp"
            android:textStyle="bold" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="30dp"

    android:background="#5490CC">

    <!-- title -->

    <TextView
        android:id="@+id/header"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="4dp"
        android:layout_marginLeft="12dp"
        android:gravity="center_vertical"
        android:textColor="@color/blanco"
        android:textSize="16dp"
        android:textStyle="bold" />

    <!--  divider -->
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="1dp"
        android:layout_alignParentBottom="true"
        android:background="#DADADC" ></View>

</RelativeLayout>

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

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

</LinearLayout>

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

    <ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
</ListView>

</LinearLayout>
更新2

MainActivity.java

public class Model{

    private int icon;
    private String title;
    private String counter;

    private boolean isGroupHeader = false;

    public Model(String title) {
        this(-1,title,null);
        isGroupHeader = true;
    }
    public Model(int icon, String title, String counter) {
        super();
        this.icon = icon;
        this.title = title;
        this.counter = counter;
    }
    public int getIcon() {
        return icon;
    }
    public void setIcon(int icon) {
        this.icon = icon;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getCounter() {
        return counter;
    }
    public void setCounter(String counter) {
        this.counter = counter;
    }
    public boolean isGroupHeader() {
        return isGroupHeader;
    }
    public void setGroupHeader(boolean isGroupHeader) {
        this.isGroupHeader = isGroupHeader;
    }
}

public class MyAdapter extends ArrayAdapter<Model> {

    private final Context context;
    private final ArrayList<Model> modelsArrayList;

    public MyAdapter(Context context, ArrayList<Model> modelsArrayList) {

        super(context, R.layout.target_item, modelsArrayList);

        this.context = context;
        this.modelsArrayList = modelsArrayList;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        // 1. Create inflater 
        LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        // 2. Get rowView from inflater

        View rowView = null;
        if(!modelsArrayList.get(position).isGroupHeader()){
            rowView = inflater.inflate(R.layout.target_item, parent, false);

            // 3. Get icon,title & counter views from the rowView
            ImageView imgView = (ImageView) rowView.findViewById(R.id.item_icon); 
            TextView titleView = (TextView) rowView.findViewById(R.id.item_title);
            TextView counterView = (TextView) rowView.findViewById(R.id.item_counter);

            // 4. Set the text for textView 
            imgView.setImageResource(modelsArrayList.get(position).getIcon());
            titleView.setText(modelsArrayList.get(position).getTitle());
            counterView.setText(modelsArrayList.get(position).getCounter());
        }`enter code here`
        else{
                rowView = inflater.inflate(R.layout.group_header_item, parent, false);
                TextView titleView = (TextView) rowView.findViewById(R.id.header);
                titleView.setText(modelsArrayList.get(position).getTitle());
        }

        // 5. retrn rowView
        return rowView;
    }
}

public class MainActivity extends ListActivity {

    public void onCreate(Bundle b) {
        super.onCreate(b);

 MyAdapter adapter = new MyAdapter(this, generateData());

   setListAdapter(adapter);
    }

private ArrayList<Model> generateData(){
        ArrayList<Model> models = new ArrayList<Model>();
        models.add(new Model("group1"));
        models.add(new Model(R.drawable.ic_action_help,"item 1","1"));
        models.add(new Model(R.drawable.ic_action_search,"item2","25"));
 return models;
    }
}

public class MainActivity extends ListActivity {

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        // extending Activity
        setContentView(R.layout.activity_main);

        // 1. pass context and data to the custom adapter
        MyAdapter adapter = new MyAdapter(this, generateData());

        //  Get ListView from activity_main.xml
        ListView list = (ListView) findViewById(android.R.id.list);


        // 3. setListAdapter
        list.setAdapter(adapter); //extending Activity
        //setListAdapter(adapter);
    }

//......
活动\u main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="48dp"
    android:background="#F3F3F3">

     <!-- icon -->
     <ImageView
         android:id="@+id/item_icon"
         android:layout_width="32dp"
         android:layout_height="32dp"
         android:layout_alignParentLeft="true"
         android:layout_marginLeft="8dp"
         android:layout_marginRight="8dp"
         android:layout_marginTop="8dp"
         android:src="@drawable/ic_action_help"
         />

    <!-- title -->
    <TextView
         android:id="@+id/item_title"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_toRightOf="@+id/item_icon"
         android:layout_alignBaseline="@+id/item_counter"
         android:textSize="18dp" />

        <!-- counter -->
        <TextView
            android:id="@+id/item_counter"
            android:layout_width="50dp"
            android:layout_height="32dp"
            android:layout_alignParentRight="true"
            android:layout_marginRight="8dp"
            android:layout_marginTop="8dp"
            android:background="@drawable/rectangle"
            android:gravity="center"
            android:textColor="#FFFFFF"
            android:textSize="12sp"
            android:textStyle="bold" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="30dp"

    android:background="#5490CC">

    <!-- title -->

    <TextView
        android:id="@+id/header"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="4dp"
        android:layout_marginLeft="12dp"
        android:gravity="center_vertical"
        android:textColor="@color/blanco"
        android:textSize="16dp"
        android:textStyle="bold" />

    <!--  divider -->
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="1dp"
        android:layout_alignParentBottom="true"
        android:background="#DADADC" ></View>

</RelativeLayout>

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

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

</LinearLayout>

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

    <ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
</ListView>

</LinearLayout>
谢谢

您的日志说明
您的内容必须有一个id属性为“android.R.id.list”的ListView

在
R.layout.activity\u main
中，您需要一个id为
android.R.id.list
的
ListView
，因为您的活动是从
ListActivity
扩展而来的。它期望一个
ListView
没有找到它。因此，在您的
main活动中
：

public class MainActivity extends ListActivity {

    public void onCreate(Bundle b) {
    super.onCreate(b);
        setContentView(R.layout.activity_main);
    }
}
然后，在您的
activity\u main.xml
中，您需要一个id为
android.R.id.list
的列表视图，您需要android.R.id.list，具体操作如下：

<ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
</ListView>

必须存在
NullPointerException
put
setContentView（R.layout.yourlayout）
在
OnCreate（）
方法中，您的
main活动
@Prag's是的，总是给出相同的错误，查找我编辑的错误日志在XML文件中放置一个列表视图。。并且错误将消失。。此外，您从未为
MainActivity
调用
setContentView（）
。请参阅。activity_main.xml的布局中有什么？如果它缺少listview，它将无法工作：我没有，没有工作。。。我添加activity_main.xml，setContentView（R.layout.activity_main）；和ListView ListView=（ListView）findViewById（R.id.list）；onCreate（），不起作用。不，您必须执行ListView lv=getListView（），现在检查您的日志猫是什么？好的，您使用的是
ListView list=（ListView）findViewById（android.R.id.list），它是
ListView list=getListView（）哦，上帝！！现在它开始工作了！！现在我只需要添加onItemClick（）和完美！！非常感谢！！！我在activity_main.xml上有相同的内容，但您没有。你有android:id=“@+id/list”而不是android:id=“@android:id/list”我希望你在更改id后不要忘记调用setContentView不，不，不，我调用了，我太奇怪了……这肯定是一个愚蠢的错误。