如何获取列表视图？

Question

如何获取列表视图 android studio.this 是我的代码public class StockSearchActivity extends AppCompatActivity {SQLiteDatabase sqLiteDatabase;DbHelper dbHelper;Cursor cursor;ListView listView;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_stock_search);    listView = findViewById(R.id.display_listview);    dbHelper = new DbHelper(this);    Cursor result = dbHelper.getAllData();    final ArrayList<String> theList = new ArrayList<>();    //get the data to the list view    if(result.getCount() == 0 ){        Toast.makeText(StockSearchActivity.this,"Databse is empty",Toast.LENGTH_LONG).show();    }else{        while (result.moveToNext()){            theList.add(result.getString(0));            theList.add(result.getString(1));            theList.add(result.getString(2));            theList.add(result.getString(3));            theList.add(result.getString(4));            ListAdapter listAdapter = new ArrayAdapter<>(this,android.R.layout.simple_expandable_list_item_1,theList);            listView.setAdapter(listAdapter);        }    }}}以下代码是我的列表视图活动代码。这是正确的。代码不起作用//getAllDatapublic Cursor getAllData(){    SQLiteDatabase db = this.getWritableDatabase();    Cursor result = db.rawQuery("SELECT * FROM  " + tbName ,null);    return result;}以上代码已在数据库类中实现。

Answer 1

设置你的Adapter外部while loop

//get the data to the list view

    if(result.getCount() == 0 ){

        Toast.makeText(StockSearchActivity.this,"Databse is empty",Toast.LENGTH_LONG).show();

    }else{

        while (result.moveToNext()){

            theList.add(result.getString(0));

            theList.add(result.getString(1));

            theList.add(result.getString(2));

            theList.add(result.getString(3));

            theList.add(result.getString(4));

        }

            ListAdapter listAdapter = new ArrayAdapter<>(this,android.R.layout.simple_expandable_list_item_1,theList);

            listView.setAdapter(listAdapter);

    }

Answer 2

你的问题在下一行

    SQLiteDatabase db = this.getWritableDatabase();

当您尝试从数据库中获取数据时，它应该以可读模式打开，如下所示。

    SQLiteDatabase db = this.getReadableDatabase();