數據庫值檢索錯誤 - 關於

Question

我是新來的android，我想從基於listview值的sqlite數據庫中檢索值。我試圖使用字符串變量來檢索值。如果我直接用變量中的值代替，我可以做到這一點。

繼此之後，我發佈了我的代碼善意幫助我解決這個問題。

DBhelper.java

public class DBHelper extends SQLiteOpenHelper{ 

public SQLiteDatabase DB; 
public String DBPath; 
public static String DBName = "VERIFY ME1.sqlite3"; 
public static final int version = '1'; 
public static Context currentContext; 
public static String tableName = "FORM2"; 

public DBHelper(Context context) { 
    super(context, DBName, null, version); 
    currentContext = context; 
    DBPath = "/data/data/" + context.getPackageName() + "/databases"; 
    createDatabase(); 
    Oninsert(DB); 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    // TODO Auto-generated method stub 

} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    // TODO Auto-generated method stub 

} 

private void createDatabase() { 
    boolean dbExists = checkDbExists(); 

    if (dbExists) { 
     // do nothing 
    } 
    else { 
     DB = currentContext.openOrCreateDatabase(DBName, 0, null); 
     DB.execSQL("CREATE TABLE IF NOT EXISTS " +tableName +" (AppNo VARCHAR, AppName VARCHAR," + 
       " Area VARCHAR, FHcode INT(3));"); 


    }} 

private boolean checkDbExists() { 
    SQLiteDatabase checkDB = null; 

    try { 
     String myPath = DBPath + DBName; 
     checkDB = SQLiteDatabase.openDatabase(myPath, null, 
       SQLiteDatabase.OPEN_READONLY); 

    } catch (SQLiteException e) { 

     // database does't exist yet. 

    } 

    if (checkDB != null) { 

     checkDB.close(); 

    } 

    return checkDB != null ? true : false; 
} 
private void Oninsert(SQLiteDatabase dB2) { 
    // TODO Auto-generated method stub 
    DB = currentContext.openOrCreateDatabase(DBName, 0, null); 
    DB.execSQL("INSERT INTO " + 
      tableName + 
      " Values ('M001','shumi','India',250);"); 
    DB.execSQL("INSERT INTO " + 
      tableName + 
      " Values ('C002','sarah','India',251);"); 
    DB.execSQL("INSERT INTO " + 
      tableName + 
      " Values ('D003','Lavya','USA',252);"); 
    DB.execSQL("INSERT INTO " + 
      tableName + 
      " Values ('V004','Avi','EU',253);"); 
    DB.execSQL("INSERT INTO " + 
      tableName + 
      " Values ('T005','Shenoi','Bangla',254);"); 
    DB.execSQL("INSERT INTO " + 
      tableName + 
      " Values ('L006','Lamha','Australia',255);"); 

    DB.close(); 
} 

} 

ListActivity.java

public class login2 extends ListActivity implements OnItemClickListener { 

private static final login2 ListActivity = null; 
private static final AdapterView<?> parent = null; 
private static int mPosition = 0; 
private static final long id = 0; 
private ArrayList<String> results = new ArrayList<String>(); 

private String tableName = DBHelper.tableName; 
private SQLiteDatabase newDB; 
private String AppName1,ApplID,FHcode,Area; 




/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    openAndQueryDatabase(); 

    displayResultList(); 


} 
private void displayResultList() { 


    setListAdapter(new ArrayAdapter<String>(this, 
    android.R.layout.simple_list_item_1, results)); 
    getListView().setTextFilterEnabled(true); 
    getListView().setOnItemClickListener(this); 

} 



private String openAndQueryDatabase() { 
    try { 
     DBHelper dbHelper = new DBHelper(this.getApplicationContext()); 
     newDB = dbHelper.getWritableDatabase(); 

     Cursor c = newDB.rawQuery("SELECT * FROM " +tableName +"", null); 

     if (c != null) { 
      if (c.moveToFirst()) { 
       do { 
       AppName1 = c.getString(c.getColumnIndex("AppName")); 

        results.add(AppName1); 


       }while (c.moveToNext()); 
      } 
     } 
     c.close(); 
    } catch (SQLiteException se) { 
     Log.e(getClass().getSimpleName(), "Could not create or Open the database"); 
    } finally { 
     //if (newDB == null) 
     // newDB.execSQL("DELETE FROM " + tableName); 
      //newDB.close(); 
    } 
    return AppName1; 

     } 



    public void onClick(View arg0) { 


     login2 det = (login2)ListActivity; 

     det.onItemClick(parent, arg0, mPosition, id); 

    } 


@Override 
public void onItemClick(AdapterView<?> parent, View view, int position, 
     long id) { 
    // TODO Auto-generated method stub 
     String data=(String)parent.getItemAtPosition(position); 
     //showMessage("Successfully", data); 

    if (data != null) {  
    try { 
     DBHelper dbHelper = new DBHelper(this.getApplicationContext()); 
     newDB = dbHelper.getWritableDatabase(); 

     Cursor c1 = newDB.rawQuery("SELECT DISTINCT AppNo, AppName, FHcode, Area FROM " 
       +tableName +" where AppName ="+data+"" ,null); 


     if (c1 != null) { 

      if (c1.moveToFirst()) { 
       do { 

         ApplID= c1.getString(c1.getColumnIndex("AppNo")); 
         String AppName =c1.getString(c1.getColumnIndex("AppName"));  
       Area = c1.getString(c1.getColumnIndex("Area")); 
       FHcode =c1.getString(c1.getColumnIndex("FHcode")); 


       Intent intent = new Intent(getApplicationContext(), form.class); 

        //Create a bundle object 
        Bundle b = new Bundle(); 

        //Inserts a String value into the mapping of this Bundle 
        b.putString("AppName", AppName.toString()); 
        b.putString("Apprefno", ApplID.toString()); 
        b.putString("FHcode", FHcode.toString()); 
        b.putString("Area", Area.toString()); 


        //Add the bundle to the intent. 
        intent.putExtras(b); 

        //start the DisplayActivity 
        startActivity(intent); 

       } 
       while (c1.moveToNext()); 

      } 
      } 
    } 


    catch (SQLiteException se) { 
     Log.e(getClass().getSimpleName(), "Could not create or Open the database"); 
    } finally { 
     //if (newDB == null) 
      //newDB.execSQL("DELETE FROM " + tableName); 
      newDB.close(); 
    } 
    } 
}  

public void showMessage (String title, String message) 
{ 
     Builder builder=new Builder(this); 
     builder.setCancelable(true); 
     builder.setTitle(title); 
     builder.setMessage(message); 
     builder.show(); 
} 

Answer 1

你已經採取此列作爲一個整數FHcode INT（3）

，並試圖爲一個字符串值，取該是錯的

c1.getString（c1.getColumnIndex（ 「FHcode」）

變化c1.getInt **（c1.getColumnIndex（ 「FHcode」）