Question

所以我对android编程比较陌生，目前正在开发自定义listView。我想要实现的目标如下：

从数据库中检索文章列表。
从“类别”列中获取所有唯一值以创建列表类别。
使用这些类别填充listView
为每个类别点击添加一个监听器，将用户带到该类别的第一篇文章。

我已成功完成上述所有工作，但现在想要进一步发展。我在数据库中有一个状态列，其值为“已读”或“未读”。我想做的是以下几点：

如果某个类别中的所有文章都是“已阅读”，则会使该类别变灰在列表视图中，忽略对该特定项目的点击。

我完全不知道如何在列表视图中格式化单个项目...任何建议？我的代码如下：

start.java：

public class Start extends Activity {

    private ListView mainListView ;  
    private ArrayAdapter<String> listAdapter ;  

    public static final String MYDATABASE_NAME = "questions.db";
    public static final String MYDATABASE_TABLE = "questions";
    public static final int MYDATABASE_VERSION = 1;
    public static final String KEY_ID = "_id";
    public static final String KEY_CONTENT = "category";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.start);

// Query database

    SQLiteDatabase db;

    db = openOrCreateDatabase(
        "questions.db"
        , SQLiteDatabase.CREATE_IF_NECESSARY
        , null
        );
    db.setVersion(1);
    db.setLocale(Locale.getDefault());
    db.setLockingEnabled(true);

    ArrayList<String> categoryList = new ArrayList<String>();

    Cursor cur = db.query("questions", null, null, null, null, null, null);
    cur.moveToFirst();

        while (cur.isAfterLast() == false) {

            if (categoryList.contains(cur.getString(11))) {
                // do nothing
            } else {
                // add to list
                categoryList.add(cur.getString(11));
            }
            cur.moveToNext();
        }
        cur.close();     

        Collections.sort(categoryList);
        categoryList.add(0, "All");

        // Find the ListView resource.   
        mainListView = (ListView) findViewById( R.id.mainListView );  

        // Create ArrayAdapter using the category list.  
        listAdapter = new ArrayAdapter<String>(this, R.layout.simplerow, categoryList);    

        // Set the ArrayAdapter as the ListView's adapter.  
        mainListView.setAdapter( listAdapter );       

        mainListView.setTextFilterEnabled(true);
        mainListView.setOnItemClickListener(new OnItemClickListener() {
                public void onItemClick(AdapterView<?> arg0, View v, int position, long id) {
                    String clickedCat = (String) mainListView.getItemAtPosition(position);
                    finish();
                    Intent myIntent = new Intent(getApplicationContext(), NextClass.class);
                    myIntent.putExtra("passedCategory", clickedCat);
                    myIntent.putExtra("startTrigger", "go");
                    startActivity(myIntent);
                }
        });     
}  
}

start.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:background="@android:color/black">

<TextView 
    android:text="@string/categories" 
    android:layout_width="fill_parent" 
    android:layout_height="@dimen/topbar_container" 
    android:background="@drawable/topgradient" 
    android:gravity="center_vertical|center_horizontal" 
    android:textColor="@color/primarytext" 
    android:textSize="@dimen/topbar_font" 
    android:textStyle="bold"
    android:shadowColor="#000000"
        android:shadowDx="1"
        android:shadowDy="1"
        android:shadowRadius="2"></TextView>

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

</LinearLayout>

simplerow.xml

<TextView xmlns:android="http://schemas.android.com/apk/res/android"  
 android:id="@+id/rowTextView"   
 android:layout_width="fill_parent"   
 android:layout_height="wrap_content"  
 android:padding="10dp"  
 android:textSize="16sp" android:textStyle="bold">  
</TextView>

Answer 1

您需要设置ViewBinder，然后调用listAdapter.setViewBinder。

Answer 2

根据我对您的问题的理解，请尝试查看here。第一个答案看起来对你有用。

Answer 3

您需要为此创建自定义适配器：

<强> CustomAdapter.class：

public class CustomAdapter extends SimpleCursorAdapter{

    Cursor dataCursor;
    LayoutInflater mInflater;
    Context context;
    ArrayList<String[]> arrayList;

    public static HashMap<Integer,String> myList=new HashMap<Integer,String>();    

    public CustomAdapter(Context context, int layout, Cursor dataCursor, String[] from,
                    int[] to) {
            super(context, layout, dataCursor, from, to);

            this.context=context;
            this.dataCursor = dataCursor;
            mInflater = LayoutInflater.from(context);             

    }

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

            final ViewHolder holder;

            if(convertView==null)
            {
                     convertView = mInflater.inflate(R.layout.custom_listitem, null);
                     holder = new ViewHolder();                          

                     holder.textview=(TextView)convertView.findViewById(R.id.textview);
                             holder.layout=(LinearLayout)findViewById(R.id.layout);                              
                     convertView.setTag(holder);
            }
            else
            {   
                holder=(ViewHolder)convertView.getTag();
            }

            dataCursor.moveToPosition(position);

            String id=Integer.toString(dataCursor.getInt(dataCursor.getColumnIndexOrThrow("_id")));
            myList.put(position, id);  

            holder.textview.setText(dataCursor.getString(11));
            if(dataCursor.getString(dataCursor.getColumnIndex("index")).equals("read"))
            {               
                holder.layout.setBackgroundColor(Color.GRAY);               
            }

            // other code according to the functionality you want    
            return convertView;
    }   

    static class ViewHolder
    {
            TextView textview;  
            LinearLayout layout;         
    } 
}

<强> custom_listitem.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:background="#FFFFFF"  
    android:id="@+id/layout"  
    android:padding="5dip"     
    >
    <TextView  
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content"    
        android:textSize="17dip"
        android:gravity="left"      
        android:padding="5dip"  
        android:id="@+id/textview" 
    /> 
</LinearLayout>

现在，在以下活动中使用它：

<强> MainActivity.class：

...
mainListView = (ListView) findViewById( R.id.mainListView ); 
Cursor cursor = db.query("questions", null, null, null, null, null, null);

CustomAdapter ca=new CustomsAdapter(context,R.layout.custom_listitem,cursor,new String[]{"id","index"},new int[]{R.id.textview,R.id.textview});

mainListView.setAdapter(ca);

mainListView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View view, int position,
                    long id) {

                String id=CustomAdapter.myList.get(position);
                Cursor findIndex=db.query("questions", null, "_id="+id, null, null, null, null);
                findIndex.moveToFirst();
                if(findIndex.getString(findIndex.getColumnIndex("index").equals("unread"))
                {
                     // do something for "unread" categories 
                }   
        }
});
...

我不知道怎么回事，你可以禁用点击特定的列表项但但是，你可以在一定条件下做这些事情让用户感觉某些项目是不可点击的。

Android listView - 格式化特定项目

start.java：

start.xml

simplerow.xml

3 个答案: