如何将光标数据（DbHandler.java）添加到列表视图（MainActicity.java）？

Posted 2023-05-07

【中文标题】如何将光标数据（DbHandler.java）添加到列表视图（MainActicity.java）？

【英文标题】：How to add cursor data(DbHandler.java) to listview(MainActicity.java)?

【发布时间】：2018-03-28 05:32:59

【问题描述】：

我的 MainActivity.java 代码：

public class MainActivity extends Activity implements AdapterView.OnItemSelectedListener
    Spinner spinner1;
    TextView textView;
    ListView listView;

    @Override
    public void onCreate(Bundle savedInstanceState)                                                //ThisIsWorkingAsExpected(SoDontChange)
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        spinner1 = (Spinner) findViewById(R.id.spinner1);
        textView = (TextView) findViewById(R.id.textview);
        listView = (ListView) findViewById(R.id.listview);
        spinner1.setOnItemSelectedListener(this);
        loadSpinnerData();
   

    public void loadSpinnerData()                                                                 //ThisIsWorkingAsExpected(SoDontChange)
        DbHandler db = new DbHandler(getApplicationContext());
        List<String> BusNoList = db.getBusNoType();
        ArrayAdapter<String> SpinnerAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, BusNoList); SpinnerAdapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice);
        spinner1.setAdapter(SpinnerAdapter);
    

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) 
        DbHandler db = new DbHandler(getApplicationContext());
        List<String> BusRouteList = db.getBusRoute();
        ArrayAdapter<String> lvAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, BusRouteList);
        listView.setAdapter(lvAdapter);
    


    @Override
    public void onNothingSelected(AdapterView<?> parent) 

    

我的 DbHandler.java 代码：

public class DbHandler extends SQLiteOpenHelper
private static final int DATABASE_VERSION = 9;
private static final String DATABASE_NAME = "TravelMadurai";
private static final String TAG = "DbHandler";

public DbHandler(Context context)

    super(context, DATABASE_NAME, null , DATABASE_VERSION);


@Override
public void onCreate(SQLiteDatabase db)                                                         //TABLES NOT CREATINIG IF DATABASE IS ALREADY THERE

    try
    
            db.execSQL("CREATE TABLE IF NOT EXISTS MDUBusRoutes(ID INTEGER PRIMARY KEY,Bus_No_Type TEXT,From_Loc TEXT,To_Loc TEXT,Route_1 TEXT,Route_2 TEXT,Route_3 TEXT,Route_4 TEXT,Route_5 TEXT,Route_6 TEXT,Route_7 TEXT,Route_8 TEXT,Route_9 TEXT,Route_10 TEXT,Route_11 TEXT,Route_12 TEXT,Route_13 TEXT,Route_14 TEXT,Route_15 TEXT,Total_Stops INTEGER)");
            db.execSQL("INSERT INTO MDUBusRoutes(Bus_No_Type,From_Loc,To_Loc,Route_1,Route_2,Route_3,Route_4,Route_5,Route_6,Route_7,Route_8,Route_9,Route_10,Route_11,Route_12,Route_13,Route_14,Route_15,Total_Stops)VALUES('C5','c5route1','c5route2','c5route3','c5route4','c5route5','c5route6','c5route7','c5route8','c5route9','c5route10','c5route11','c5route12','c5route13','c5route14','c5route15','c5route16','c5route17',15)");
            db.execSQL("INSERT INTO MDUBusRoutes(Bus_No_Type,From_Loc,To_Loc,Route_1,Route_2,Route_3,Route_4,Route_5,Route_6,Route_7,Route_8,Route_9,Route_10,Route_11,Route_12,Route_13,Route_14,Route_15,Total_Stops)VALUES('A5','a5Route1','a5Route2','a5Route3','a5Route4','a5Route5','a5Route6','a5Route7','a5Route8','a5Route9','a5Route10','a5Route11','a5Route12','a5Route13','a5Route14','a5Route15','a5Route16','a5Route17',15)");
            db.execSQL("INSERT INTO MDUBusRoutes(Bus_No_Type,From_Loc,To_Loc,Route_1,Route_2,Route_3,Route_4,Route_5,Route_6,Route_7,Route_8,Route_9,Route_10,Route_11,Route_12,Route_13,Route_14,Route_15,Total_Stops)VALUES('B7','b7Route1','b7Route2','b7Route3','b7Route4','b7Route5','b7Route6','b7Route7','b7Route8','b7Route9','b7Route10','b7Route11','b7Route12','b7Route13','b7Route14','b7Route15','b7Route16','b7Route17',15)");
    
    catch (Exception e)
        Log.d(TAG,"ErrorCreatingTable" + e);
    




@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)

    db.execSQL("DROP TABLE IF EXISTS MDUBusRoutes" );
    onCreate(db);



public  List<String> getBusNoType()                                                             //ThisIsWorkingAsExpected(SoDontChange)

List<String> BusNoList = new ArrayList<String>();
try 
    String SelectBusNo = "SELECT * FROM MDUBusRoutes ORDER BY Bus_No_Type ASC" ;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor CursorBusNo = db.rawQuery(SelectBusNo, null);
    if (CursorBusNo.moveToFirst())
    
        do 
            BusNoList.add(CursorBusNo.getString(1));
        
        while (CursorBusNo.moveToNext());
    
    CursorBusNo.close();
    db.close();

catch (Exception ignored)
    Log.d(TAG,"Error:..........................................................................." + ignored);



return BusNoList;


public  List<String> getBusRoute()                                                             //ThisIsWorkingAsExpected(SoDontChange)

    List<String> BusRouteList = new ArrayList<String>();

    try 
        String SelectBusRoute = "SELECT * FROM MDUBusRoutes" ;
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor CursorBusRoute = db.rawQuery(SelectBusRoute, null);
        if (CursorBusRoute.moveToFirst()) 
            do 
                BusRouteList.add(CursorBusRoute.getString(2));
            
            while (CursorBusRoute.moveToNext());
        
        CursorBusRoute.close();
        db.close();
    
    catch (Exception ignored)

    
    return BusRouteList;

我的输出如下：

微调项目：

我的输出显示表格中每一行的第三列，但我想添加表格中的列。当我在微调器中选择另一个项目时，列表视图应显示 Bus_No_Type = (spinneritemselected) 的列

For example:


If I select B7 from spinner then listview should display values from b7Route1 to b7Route17. Which is already added in table.

我是安卓新手。请帮助我，我正在尝试这个很长时间

谢谢！

【问题讨论】：

如果选择 B7，ListView 应该继续显示先前选择的结果，还是应该在显示从 b7Route1 到 b7Route17 的值之前先清除旧选择？

是的，它应该先清除旧部分，然后它应该显示 b7Route1 到 b7Route17 @0X0nosugar

【参考方案1】：

如下更改您的onItemSelected。

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) 
    String bus = (String) getItem(position);
    DbHandler db = new DbHandler(getApplicationContext());
    List<String> BusRouteList = db.getBusRoute(bus);
    ArrayAdapter<String> lvAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, BusRouteList);
    listView.setAdapter(lvAdapter);

和getBusRoute 如下。

public  List<String> getBusRoute(String bus)                                                             //ThisIsWorkingAsExpected(SoDontChange)

    List<String> BusRouteList = new ArrayList<String>();

    try 
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor CursorBusRoute = db.query("MDUBusRoutes", new String[] "From_Loc","To_Loc","Route_1","Route_2","Route_3","Route_4","Route_5","Route_6","Route_7","Route_8","Route_9","Route_10","Route_11","Route_12","Route_13","Route_14","Route_15", "Bus_No_Type=?", new String[]  bus , null, null, null, null);
        if (CursorBusRoute.moveToFirst()) 
            do 
                BusRouteList.add(CursorBusRoute.getString(2));
            
            while (CursorBusRoute.moveToNext());
        
        CursorBusRoute.close();
        db.close();
    
    catch (Exception ignored)

    
    return BusRouteList;

【讨论】：

非常感谢 NishantBhakta 兄弟。您的回答 100% 有效。非常感谢。@NishantBhakta

如果你觉得这个答案有帮助，你可以投票这个答案。