"ArrayAdapter需要资源ID为TextView"xml问题

Question

我试图设置我的视图以显示ListView我想要显示的文件(文本文件)时收到错误.我很确定它与xml有关.我只想显示来自的信息this.file = fileop.ReadFileAsList("Installed_packages.txt");.我的代码:

public class Main extends Activity {
    private TextView tv;
    private FileOperations fileop;
    private String[] file;

    /** Called when the activity is first created. */       
    @Override
    public void onCreate(Bundle savedInstanceState) {           
        super.onCreate(savedInstanceState); 
        this.fileop = new FileOperations(); 
        this.file = fileop.ReadFileAsList("Installed_packages.txt"); 
        setContentView(R.layout.main);
        tv = (TextView) findViewById(R.id.TextView01);
        ListView lv = new ListView(this);
        lv.setTextFilterEnabled(true); 
        lv.setAdapter(new ArrayAdapter<String>(this, R.layout.list_item, this.file)); 
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() { 

              public void onItemClick(AdapterView<?> parent, View view,     int position, long id) { 
                    // When clicked, show a toast with the TextView text 
                    Toast.makeText(getApplicationContext(), ((TextView) view).getText(), Toast.LENGTH_SHORT).show(); 
              } 
        });         
        setContentView(lv);
    }

}

list_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" 
    android:padding="10dp"   
    android:textSize="16sp"   
    android:textColor="#000">

</LinearLayout>

main.xml:

<?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"
    android:weightSum="1">
<ScrollView
    android:id="@+id/SCROLLER_ID"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:scrollbars="vertical"
    android:fillViewport="true">
        <TextView  
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:padding="5sp"
        android:id="@+id/TextView01"
        android:text="@string/hello"/>
    </ScrollView>

</LinearLayout>

Answer 1

该ArrayAdapter需要的资源ID是一个TextView XML异常意味着你不提供什么ArrayAdapter期望.当您使用此构造函数时:

new ArrayAdapter<String>(this, R.layout.a_layout_file, this.file)

R.Layout.a_layout_file必须是只包含一个XML布局文件的ID TextView(在TextView 不能被另一个布局包裹,就像一个LinearLayout,RelativeLayout等等!),这样的事情:

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" 
    // other attributes of the TextView
/>

如果您希望列表行布局有点不同,那么一个简单的TextView小部件使用此构造函数:

new ArrayAdapter<String>(this, R.layout.a_layout_file, 
   R.id.the_id_of_a_textview_from_the_layout, this.file)

在哪里提供id可以包含各种视图的布局,但也必须包含一个TextViewwith和id(第三个参数),并将其传递给您,ArrayAdapter以便知道Strings在行布局中的位置.

Answer 2

愿在这里

listitem.xml

<?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" >

     <TextView
         android:id="@+id/textview"
         android:layout_width="match_parent"
         android:layout_height="match_parent" >
     </TextView>
</LinearLayout>

Java代码:

 String[] countryArray = {"India", "Pakistan", "USA", "UK"};
 ArrayAdapter adapter = new ArrayAdapter<String>(this, R.layout.listitem,R.id.textview, countryArray);
 ListView listView = (ListView) findViewById(R.id.listview);
 listView.setAdapter(adapter);