3

虽然这个问题在这里被问过很多次，但我只是找不到适合我的代码的正确答案。我意识到这可能是一件小事，但我似乎无法找到问题所在，因为我只是对此很陌生。

这是我在DatabaseHelper类中的代码getClientNames ：

public Cursor getSitesByClientname(String id) {
    String[] args={id};

Cursor myCursor = db.rawQuery("SELECT client_sitename FROM " + CLIENT_SITES_TABLE + " WHERE client_id=?", args);
        String results = "";
        /*int count = myCursor.getCount();
        String[] results = new String[count + 1];
        int i = 0;*/

         if (myCursor != null) {           
                if(myCursor.getCount() > 0)
                {   
                    for (myCursor.moveToFirst(); !myCursor.isAfterLast(); myCursor.moveToNext())
                    {
                        results = results + myCursor.getString(myCursor.getColumnIndex("client_sitename")); 
                    }
                }
            }
            return results;
}

一个问题是我正在向“光标”返回一个“字符串”，但我不确定解决这个问题的最佳方法是什么，因为我认为我应该返回一个光标。

这是我要显示数据的ClientSites类：

public class ClientSites extends Activity {

//public final static String ID_EXTRA="com.example.loginfromlocal._ID";

        private DBUserAdapter dbHelper = null;
    private Cursor ourCursor = null;
    private Adapter adapter=null;


    @SuppressWarnings("deprecation")
    @SuppressLint("NewApi")
    public void onCreate(Bundle savedInstanceState) {
        try
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.client_sites);

            Intent i = getIntent();
            String uID = String.valueOf(i.getIntExtra("userID", 0));

            ListView myListView = (ListView)findViewById(R.id.myListView);

            dbHelper = new DBUserAdapter(this);

            //dbHelper.createDatabase();

            dbHelper.openDataBase();

            ourCursor = dbHelper.getSitesByClientname(uID);
            Log.e("ALERT", uID.toString());

            startManagingCursor(ourCursor);
            Log.e("ERROR", "After start manage cursor: ");

            //@SuppressWarnings("deprecation") 
            //SimpleCursorAdapter adapter = new SimpleCursorAdapter(getBaseContext(), R.id.myListView, null, null, null);
            CursorAdapter adapter = new SimpleCursorAdapter(this, R.id.myListView, null, null, null, 0);
            adapter = new Adapter(ourCursor);

            //Toast.makeText(ClientSites.this, "Booo!!!", Toast.LENGTH_LONG).show();

            myListView.setAdapter(adapter);

            myListView.setOnItemClickListener(onListClick);


        }
        catch (Exception e)
        {
            Log.e("ERROR", "XXERROR IN CODE: " + e.toString());
            e.printStackTrace();
        } 

    }

    private AdapterView.OnItemClickListener onListClick=new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent,
                                View view, int position,
                                long id) 
        {
            Intent i=new Intent(ClientSites.this, InspectionPoints.class);

            i.putExtra(ID_EXTRA, String.valueOf(id));
            startActivity(i);

        }
    };


    class Adapter extends CursorAdapter {
        @SuppressWarnings("deprecation")
        Adapter(Cursor c) {
          super(ClientSites.this, c);
        }

        //@Override
        public void bindView(View row, Context ctxt,
                           Cursor c) {
            Holder holder=(Holder)row.getTag();
            holder.populateFrom(c, dbHelper);
        }
        @Override
        public View newView(Context ctxt, Cursor c,
                           ViewGroup parent) {
          LayoutInflater inflater=getLayoutInflater();
          View row = inflater.inflate(R.layout.row, parent, false);
          Holder holder=new Holder(row);
          row.setTag(holder);
          return(row);
        }
      }

    static class Holder {
        private TextView name=null;

        Holder(View row) {
            name=(TextView)row.findViewById(R.id.ingredientText);
        }

        void populateFrom(Cursor c, DBUserAdapter r) {
            name.setText(r.getName(c));
        }
    }
}

这是我现在用来尝试在 Listview 中显示数据的代码。我从最初的尝试中对其进行了一些更改，但仍然不确定我做错了什么。

public void onCreate(Bundle savedInstanceState) {
        try
        {
            super.onCreate(savedInstanceState);
            //setContentView(R.layout.client_sites);

            Intent i = getIntent();
            String uID = String.valueOf(i.getIntExtra("userID", 0));
            //int uID = i.getIntExtra("userID", 0);

            //ListView myListView = (ListView)findViewById(R.id.myListView);

            dbHelper = new DBUserAdapter(this);

            dbHelper.createDatabase();

            dbHelper.openDataBase();

            String[] results = dbHelper.getSitesByClientname(uID);

            //setListAdapter(new ArrayAdapter<String>(ClientSites.this, R.id.myListView, results));
            //adapter = new ArrayAdapter<String>(ClientSites.this, R.id.myListView, results);
            setListAdapter(new ArrayAdapter<String>(ClientSites.this, R.layout.client_sites, results));

            //ListView myListView = (ListView)findViewById(R.id.myListView);
            ListView listView = getListView();
            listView.setTextFilterEnabled(true);

            //ourCursor = dbHelper.getSitesByClientname(uID);
            //Log.e("ALERT", uID.toString());

            //startManagingCursor(ourCursor);
            //Log.e("ERROR", "After start manage cursor: ");

            //@SuppressWarnings("deprecation") 
            //SimpleCursorAdapter adapter = new SimpleCursorAdapter(getBaseContext(), R.id.myListView, null, null, null); // LOOK AT THIS IN THE MORNING!!!!!!!!!!! 
            //CursorAdapter adapter = new SimpleCursorAdapter(this, R.id.myListView, null, null, null, 0);
            //adapter = new Adapter(ourCursor);

            //Toast.makeText(ClientSites.this, "Booo!!!", Toast.LENGTH_LONG).show();

            //myListView.setAdapter(adapter);

            //myListView.setOnItemClickListener(onListClick);
4

2 回答 2

2

我从数据库创建了一个 Listview。这是我用于我的应用程序的代码

这是数据库处理程序的一部分。它将为我的列表视图返回一个类别列表。如果这是您需要的，它可以返回一个字符串列表。

public List<Category> getAllCategorys() {
        ArrayList<Category> categoryList = new ArrayList<Category>();
        // Select All Query
        String selectQuery = "SELECT  * FROM " + TABLE_CATEGORY;
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
        // looping through all rows and adding to list
        try{
            if (cursor.moveToFirst()) {
                do {
                    Category category = new Category();
                    category.setID(Integer.parseInt(cursor.getString(0)));
                    category.setCategory(cursor.getString(1));
                    // Adding category to list
                    categoryList.add(category);
                } while (cursor.moveToNext());
            }   
        }finally{
            cursor.close();
        }   
        db.close();
        // return category list
        return categoryList;

这是我通过调用数据库填充 ListView 的方法。

int size = db.getCategoryCount();
List<Category> categoryList = db.getAllCategorys();

category_data = new String[size-1];
int i=0;
for(Category cn : categoryList)
{   
    category_data[i] = cn.getCategory(); // get the name of the category and add it to array
    i++;   
} 

listAdapter = new ArrayAdapter<String>(this, R.layout.categoryrow, category_data);
listViw.setAdapter(listAdapter);

编辑：这是应该为你工作的东西

public List<String> getSitesByClientname(String id) {
    String[] args={id};
    ArrayList<String> result = new ArrayList<String>();
    SQLiteDatabase db = this.getWritableDatabase();

    Cursor myCursor = db.rawQuery("SELECT client_sitename FROM " + CLIENT_SITES_TABLE +      " WHERE client_id=?", args);

    try{
       if (myCursor.moveToFirst()){
           do{
              result.add(myCursor.getString(myCusor.getString(myCursor.getColumnIndex("client_sitename"));
           }while(myCursor.moveToNext());
        }
    }finally{
         myCursor.close();
    }
    db.close();
    return result;
}

像这样使用它

List<String> sites_data = dbHelper.getSitesByClientname(uID);

result_data = new String[sites_data.size()];
int i=0;
for(String s : sites_data)
{   
    result_data[i] = s; // get the name of the category and add it to array
    i++;   
} 

listAdapter = new ArrayAdapter<String>(this, R.layout.client_sites, result_data);
listViw.setAdapter(listAdapter);
于 2013-03-12T19:24:54.643 回答
1

如果你想从 dbHelper 返回游标，你可以做这样的事情......

public Cursor getSitesByClientname(String id) {
    String[] args={id};

return db.rawQuery("SELECT client_sitename FROM " + CLIENT_SITES_TABLE + " WHERE client_id=?", args);
}

我还需要一些时间阅读listview 教程

于 2013-03-12T14:30:58.883 回答