无法从CursorWindow读取0行，列-1显示记录

问题描述：

美好的一天，我试图检索我的数据并以简单的方式显示它们。这里是我的示例代码：SQLiteLocalDatabase的.java无法从CursorWindow读取0行，列-1显示记录

public class SQLiteLocalDatabase extends SQLiteOpenHelper{ 


private SQLiteDatabase sqLiteDatabase; 
private static final String DB_NAME = "project.db"; 
private static final int VERSION = 1; 


public static final String DB_TABLE = " user "; 
public static final String ID = " _id "; 
public static final String FULL_NAME = " fullname "; 
public static final String LOCATION = " location "; 
public static final String EMAIL_ADD = " email "; 
public static final String PASSWORD = " password "; 


public SQLiteLocalDatabase(Context context) { 
    super(context, DB_NAME, null, VERSION); 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    String queryTable = " CREATE TABLE " + DB_TABLE + "(" + ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+ FULL_NAME + " TEXT , " + LOCATION + " TEXT NOT NULL, " + EMAIL_ADD + " TEXT , " + PASSWORD + " TEXT " + ") "; 

    //setUpDb(); 
    db.execSQL(queryTable); 
} 

public void setUpDb(){ 
    //TO OPEN DATABASE - RE-WRITABLE 
    sqLiteDatabase = getWritableDatabase(); 

} 

public void closeTransactionDb(){ 
    //CLOSE DB IF OPEN 
    if(sqLiteDatabase != null && sqLiteDatabase.isOpen()){ 
     sqLiteDatabase.close(); 
    } 
} 

//INSERT DATA 
public long insert(int id,String fullname, String location,String email,String password){ 

    //CONTENT VALUE contains name-value-pairs 
    ContentValues values = new ContentValues(); 

    if(id != -1) { 
     values.put(ID,id); 
     values.put(FULL_NAME, fullname); 
     values.put(LOCATION, location); 
     values.put(EMAIL_ADD, email); 
     values.put(PASSWORD, password); 
    } 
    //Object Table, column, values 
    return sqLiteDatabase.insert(DB_TABLE, null, values); 

} 

//UPDATE 
public long update(int id, String fullname,String location,String email, String password){ 
    //CONTENT VALUE contains name-value-pairs 
     ContentValues values = new ContentValues(); 
     values.put(FULL_NAME,fullname); 
     values.put(LOCATION,location); 
     values.put(EMAIL_ADD,email); 
     values.put(PASSWORD,password); 

    //WHERE 
     String where = ID + " = " +id; 

    //Object Table, values, destination-id 
    return sqLiteDatabase.update(DB_TABLE, values, where, null); 
} 

//DELETE 
// 
public long delete(int id){ 
    //WHERE 
    String where = ID + " = " +id; 

    //Object Table, values, destination-id 
    return sqLiteDatabase.delete(DB_TABLE, where, null); 
} 

public Cursor getAllRecords(){ 

    String queryDB = "SELECT * FROM " + DB_TABLE; 
    return sqLiteDatabase.rawQuery(queryDB, null); 
} 

public Cursor getSingleRecord(){ 

    String querySingleRecord = "SELECT * FROM " + DB_TABLE + "WHERE _id = " +ID; 
    return sqLiteDatabase.rawQuery(querySingleRecord,null); 
} 


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

}

对于我的主：AddItemsActivity的.java

public class AddItemsActivity extends AppCompatActivity implements View.OnClickListener{ 


SQLiteLocalDatabase sqLiteLocalDatabase; 

    TextView textViewDbData; 
    EditText editTextFullName; 
    EditText editTextAddress; 
    EditText editTextEmailAdd; 
    EditText editTextPassword; 
    EditText editTextIDNO; 
    Button btnSave; 
    Button btnUpdate; 
    Button btnSearch; 
    Button btnDelete; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_add_items); 

    sqLiteLocalDatabase = new SQLiteLocalDatabase(AddItemsActivity.this); 

    //CALL FUNCTION 
    setUpWidgets(); 
} 

public void setUpWidgets(){ 

    textViewDbData = (TextView) findViewById(R.id.textViewDbData); 
    editTextFullName = (EditText) findViewById(R.id.editTextViewAddFullName); 
    editTextAddress = (EditText) findViewById(R.id.editTextAddLocation); 
    editTextEmailAdd = (EditText) findViewById(R.id.editTextAddEmailAddress); 
    editTextPassword = (EditText) findViewById(R.id.editTextRegPassword); 
    editTextIDNO = (EditText) findViewById(R.id.editTextAddID); 

    btnSave = (Button) findViewById(R.id.buttonAddContacts); 
    btnSave.setOnClickListener(this); 
    btnUpdate = (Button) findViewById(R.id.buttonUpdate); 
    btnUpdate.setOnClickListener(this); 
    btnSearch = (Button) findViewById(R.id.buttonDeleteRecord); 
    btnSearch.setOnClickListener(this); 
    btnDelete = (Button) findViewById(R.id.buttonShowRecords); 
    btnDelete.setOnClickListener(this); 

} 

public void clearTextFields(){ 
    editTextFullName.setText(""); 
    editTextAddress.setText(""); 
    editTextEmailAdd.setText(""); 
    editTextPassword.setText(""); 
    editTextIDNO.setText(""); 

} 

@Override 
public void onClick(View v) { 

    String fullName = editTextFullName.getText().toString().trim(); 
    String location = editTextAddress.getText().toString().trim(); 
    String emailAdd = editTextEmailAdd.getText().toString().trim(); 
    String password = editTextPassword.getText().toString().trim(); 


    switch (v.getId()){ 
     case R.id.buttonAddContacts: 
      //IF result == -1 
      long result = sqLiteLocalDatabase.insert(Integer.parseInt(getValue(editTextIDNO)), fullName, location, emailAdd, password); 
      if(result == -1){ 
       Toast.makeText(AddItemsActivity.this, "Error: Someone own that Id",Toast.LENGTH_LONG).show(); 
      }else 
      { 
       Toast.makeText(AddItemsActivity.this, "Success Id: " +result,Toast.LENGTH_LONG).show(); 
       clearTextFields(); 
      } 

      break; 

     case R.id.buttonUpdate: 

      if(editTextIDNO.getText().equals("")){ 

       Toast.makeText(AddItemsActivity.this, "Please Enter User ID ",Toast.LENGTH_LONG).show(); 

      } 
      else { 

       long update = sqLiteLocalDatabase.update(Integer.parseInt(getValue(editTextIDNO)), 
         getValue(editTextFullName), 
         getValue(editTextAddress), 
         getValue(editTextEmailAdd), 
         getValue(editTextPassword) 
       ); 

       if (update == 0) { 
        Toast.makeText(AddItemsActivity.this, "Error Updating ", Toast.LENGTH_LONG).show(); 
       } else if (update == -1) { 
        Toast.makeText(AddItemsActivity.this, "Successfully Modified", Toast.LENGTH_LONG).show(); 
        clearTextFields(); 
       } else { 
        Toast.makeText(AddItemsActivity.this, "Error All data updated Id: " + update, Toast.LENGTH_LONG).show(); 
       } 
      } 
      break; 

     case R.id.buttonDeleteRecord: 

      long delete = sqLiteLocalDatabase.delete(Integer.parseInt(getValue(editTextIDNO))); 
      if(delete == 0) { 
       Toast.makeText(AddItemsActivity.this, "Error Delete", Toast.LENGTH_LONG).show(); 
      } else 
      { 
       Toast.makeText(AddItemsActivity.this, "Success Delete", Toast.LENGTH_LONG).show(); 
       clearTextFields(); 
      } 
      break; 

     case R.id.buttonShowRecords: 

      StringBuffer finalData = new StringBuffer(); 
      Cursor cursor = sqLiteLocalDatabase.getAllRecords(); 

      for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()){ 

       finalData.append(cursor.getLong(cursor.getColumnIndex(sqLiteLocalDatabase.ID))); 
       finalData.append(" - "); 

       finalData.append(cursor.getString(cursor.getColumnIndex(sqLiteLocalDatabase.FULL_NAME))); 
       finalData.append(" - "); 

       finalData.append(cursor.getString(cursor.getColumnIndex(sqLiteLocalDatabase.LOCATION))); 
       finalData.append(" - "); 

       finalData.append(cursor.getInt(cursor.getColumnIndex(sqLiteLocalDatabase.EMAIL_ADD))); 
       finalData.append(" - "); 

       finalData.append(cursor.getInt(cursor.getColumnIndex(sqLiteLocalDatabase.PASSWORD))); 
       finalData.append("\n"); 

      } 
      textViewDbData.setText(finalData); 
      break; 
    } 
} 

public String getValue(EditText editText){ 
    return editText.getText().toString().trim(); 

} 

@Override 
protected void onStart() { 
    super.onStart(); 
    sqLiteLocalDatabase.setUpDb(); 

} 

@Override 
protected void onStop() { 
    super.onStop(); 
    sqLiteLocalDatabase.closeTransactionDb(); 
}

我的问题是，在追加部分getAllRecords。 logcat的：

确保光标包含您提到的所有列。 – ELITE

答

这是因为越来越列索引等cursor.getColumnIndex(sqLiteLocalDatabase.ID)返回-1的方法之一。

确保Cursor包含您正在检索的所有列，并检查getColumnIndex方法是否不返回-1。

if(cursor.getColumnIndex(sqLiteLocalDatabase.ID) != -1) { 
    finalData.append(cursor.getLong(cursor.getColumnIndex(sqLiteLocalDatabase.ID))); 
    finalData.append(" - "); 
}

同样检查所有条件。

希望它能工作。

如何做到这一点？我的意思是我单独给他们打电话ID，FULLNAME，LOCATION，EMAIL_ADD，PASSWORD。 – RoCk

在获得'for'循环中的记录之前添加'if（cursor.getColumnIndex（COL_NAME）！= -1）'条件，我添加了示例如何做到这一点。 – ELITE

我遵循解决方案。 :)它现在不会产生错误。但没有数据显示。 :( if（cursor.getColumnIndex（sqLiteLocalDatabase.ID）！= -1 && cursor.getColumnIndex（sqLiteLocalDatabase.FULL_NAME）！= -1 && cursor.getColumnIndex（sqLiteLocalDatabase.LOCATION）！= -1 && cursor.getColumnIndex sqLiteLocalDatabase.LOCATION）！= -1 && cursor.getColumnIndex（sqLiteLocalDatabase.EMAIL_ADD）！= -1 && cursor.getColumnIndex（sqLiteLocalDatabase.PASSWORD）！= -1）{ – RoCk

无法从CursorWindow读取0行，列-1显示记录

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