Android ArrayList outOfBoundsException数据库错误

嘿，当我在应用程序上运行测试时，我开始从数据库中删除数据库值。一旦我这样做了，我就开始犯这个错误 原因：java.lang.IndexOutOfBoundsException:索引：0，大小：0

它适用于这行代码。 PasswordResults PasswordResults=password.get0；我对此感到困惑，因为在我删除数据库中的某些数据之前，get0总是会在我的recyclerView上获取所选行

public void addPassword(String n, String w, String u, String p, String d) {
    // get database.
    SQLiteDatabase db = getWritableDatabase();

    try {
        // add scores.
        ContentValues values = new ContentValues();
        values.put(COLUMN_NAME, n);
        values.put(COLUMN_WEBSITE, w);
        values.put(COLUMN_USERNAME, u);
        values.put(COLUMN_PASSWORD, p);
        values.put(COLUMN_DESC, d);

        // insert will handle null values. closing.
        db.insert(TABLE_NAME, "", values);
        db.close();
    } catch (Exception e) {
        e.getLocalizedMessage();
    }
}

public void removePassword(String id){
    // get database.
    SQLiteDatabase db = getWritableDatabase();

    // delete database then close or print error.
    try {
        db.delete(TABLE_NAME, "_id="+id, null);
        db.close();
    } catch(Exception e) {
        e.getLocalizedMessage();
    }
}

public void updatePassword(String id, String n, String w, String u, String p, String d) {
    // get database.
    SQLiteDatabase db = getWritableDatabase();

    //update database then close or print error.
    try {
        ContentValues values = new ContentValues();
        values.put(COLUMN_ID, id);
        values.put(COLUMN_NAME, n);
        values.put(COLUMN_WEBSITE, w);
        values.put(COLUMN_USERNAME, u);
        values.put(COLUMN_PASSWORD, p);
        values.put(COLUMN_DESC, d);
        db.update(TABLE_NAME, values, "_id="+id, null);
        db.close();
    } catch (Exception e) {
        e.getLocalizedMessage();
    }
}

public ArrayList<PasswordResults> getPasswords() {
    // get database, password array, and select statement.
    passwords = new ArrayList<>();
    String refQuery = "Select "+COLUMN_NAME+", "+COLUMN_WEBSITE+", "+COLUMN_USERNAME+", "+COLUMN_PASSWORD+", "+COLUMN_DESC+" FROM "+TABLE_NAME;
    SQLiteDatabase db = getWritableDatabase();

    // link to database
    Cursor cursor = db.rawQuery(refQuery, null);
    if(cursor.moveToFirst()) {
        do {
            PasswordResults passwordResults = new PasswordResults();
            passwordResults.entryName = cursor.getString(0);
            passwordResults.website = cursor.getString(1);
            passwordResults.username = cursor.getString(2);
            passwordResults.password = cursor.getString(3);
            passwordResults.description = cursor.getString(4);
            passwords.add(passwordResults);
        } while(cursor.moveToNext());
    }
    db.close();
    return passwords;
}

public ArrayList<PasswordResults> getSelectedPassword(String id) {
    // get database, password array, and select statement.
    passwords = new ArrayList<>();
    String refQuery = "Select "+COLUMN_NAME+", "+COLUMN_WEBSITE+", "+COLUMN_USERNAME+", "+COLUMN_PASSWORD+", "+COLUMN_DESC+" FROM "+TABLE_NAME+" WHERE "+COLUMN_ID+" = "+id;
    SQLiteDatabase db = getWritableDatabase();

    // link to database
    Cursor cursor = db.rawQuery(refQuery, null);
    if(cursor.moveToFirst()) {
        do {
            PasswordResults passwordResults = new PasswordResults();
            passwordResults.id = Integer.parseInt(id);
            passwordResults.entryName = cursor.getString(0);
            passwordResults.website = cursor.getString(1);
            passwordResults.username = cursor.getString(2);
            passwordResults.password = cursor.getString(3);
            passwordResults.description = cursor.getString(4);
            passwords.add(passwordResults);
        } while(cursor.moveToNext());
    }
    db.close();
    return passwords;
}

这是我的密码管理器的代码，我在那里得到了错误信息。 我正在传递一个checker整数和一个字符串，该字符串包含用户单击的行的selectedID。我尝试过使用PasswordResults PasswordResults=password.getInteger.parseIntid，认为这样做可行，但实际上不行

// method to load correct screen based on user input.
    public void loadScreen(int c, String id){
        // checking if it is a previous entry.
        if(c == 1) {
            // Since there already is a password set button to "Show Password"
            password_btn.setText("Show");
            // getting selected passwords data.
            password = db.getSelectedPassword(id);

            // GETTING ERROR HERE
            PasswordResults passwordResults = password.get(0);

            idSelected = id;
            entryName_et.setText(passwordResults.entryName);
            website_et.setText(passwordResults.website);
            username_et.setText(passwordResults.username);

            realPassword = passwordResults.password;
            // dont show real password yet.
            if(showPW == 1)
                password_et.setText(realPassword);
             else 
                password_et.setText("***********");

            desc_et.setText(passwordResults.description);

            // make delete button visible since user could want to delete entry.
            delete_btn.setVisibility(View.VISIBLE);
        } else {
            // since user is creating a new entry dont show delete button.
            delete_btn.setVisibility(View.GONE);
        }
    }

这是我的数据库类的代码，它处理数据库中信息的检索

public void addPassword(String n, String w, String u, String p, String d) {
    // get database.
    SQLiteDatabase db = getWritableDatabase();

    try {
        // add scores.
        ContentValues values = new ContentValues();
        values.put(COLUMN_NAME, n);
        values.put(COLUMN_WEBSITE, w);
        values.put(COLUMN_USERNAME, u);
        values.put(COLUMN_PASSWORD, p);
        values.put(COLUMN_DESC, d);

        // insert will handle null values. closing.
        db.insert(TABLE_NAME, "", values);
        db.close();
    } catch (Exception e) {
        e.getLocalizedMessage();
    }
}

public void removePassword(String id){
    // get database.
    SQLiteDatabase db = getWritableDatabase();

    // delete database then close or print error.
    try {
        db.delete(TABLE_NAME, "_id="+id, null);
        db.close();
    } catch(Exception e) {
        e.getLocalizedMessage();
    }
}

public void updatePassword(String id, String n, String w, String u, String p, String d) {
    // get database.
    SQLiteDatabase db = getWritableDatabase();

    //update database then close or print error.
    try {
        ContentValues values = new ContentValues();
        values.put(COLUMN_ID, id);
        values.put(COLUMN_NAME, n);
        values.put(COLUMN_WEBSITE, w);
        values.put(COLUMN_USERNAME, u);
        values.put(COLUMN_PASSWORD, p);
        values.put(COLUMN_DESC, d);
        db.update(TABLE_NAME, values, "_id="+id, null);
        db.close();
    } catch (Exception e) {
        e.getLocalizedMessage();
    }
}

public ArrayList<PasswordResults> getPasswords() {
    // get database, password array, and select statement.
    passwords = new ArrayList<>();
    String refQuery = "Select "+COLUMN_NAME+", "+COLUMN_WEBSITE+", "+COLUMN_USERNAME+", "+COLUMN_PASSWORD+", "+COLUMN_DESC+" FROM "+TABLE_NAME;
    SQLiteDatabase db = getWritableDatabase();

    // link to database
    Cursor cursor = db.rawQuery(refQuery, null);
    if(cursor.moveToFirst()) {
        do {
            PasswordResults passwordResults = new PasswordResults();
            passwordResults.entryName = cursor.getString(0);
            passwordResults.website = cursor.getString(1);
            passwordResults.username = cursor.getString(2);
            passwordResults.password = cursor.getString(3);
            passwordResults.description = cursor.getString(4);
            passwords.add(passwordResults);
        } while(cursor.moveToNext());
    }
    db.close();
    return passwords;
}

public ArrayList<PasswordResults> getSelectedPassword(String id) {
    // get database, password array, and select statement.
    passwords = new ArrayList<>();
    String refQuery = "Select "+COLUMN_NAME+", "+COLUMN_WEBSITE+", "+COLUMN_USERNAME+", "+COLUMN_PASSWORD+", "+COLUMN_DESC+" FROM "+TABLE_NAME+" WHERE "+COLUMN_ID+" = "+id;
    SQLiteDatabase db = getWritableDatabase();

    // link to database
    Cursor cursor = db.rawQuery(refQuery, null);
    if(cursor.moveToFirst()) {
        do {
            PasswordResults passwordResults = new PasswordResults();
            passwordResults.id = Integer.parseInt(id);
            passwordResults.entryName = cursor.getString(0);
            passwordResults.website = cursor.getString(1);
            passwordResults.username = cursor.getString(2);
            passwordResults.password = cursor.getString(3);
            passwordResults.description = cursor.getString(4);
            passwords.add(passwordResults);
        } while(cursor.moveToNext());
    }
    db.close();
    return passwords;
}

这可能是一个很容易的修复方法，就像我在这里介绍的一半内容一样，但提前感谢您的帮助。

如果您的id是字符串，您必须将查询中的+id更改为+''+id+''，因此它将被视为字符串

String refQuery = "Select "+COLUMN_NAME+", "+COLUMN_WEBSITE+", "+COLUMN_USERNAME+", "+COLUMN_PASSWORD+", "+COLUMN_DESC+" FROM "+TABLE_NAME+" WHERE "+COLUMN_ID+" = "+ '"' + id + '"';

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getSelectedPassword未选择任何行的赔率。不会输入do…while构造，即cursor.moveToFirst返回false，因此返回的结果是没有元素的空ArrayList，因此索引0超出范围

检查ArrayList的大小，仅当该大小大于0时才尝试获取密码。可能是烤面包片或其他东西来表示错误

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显然，您需要确定为什么没有找到正在传递的id，这将是根本原因。

请从日志中添加堆栈跟踪，以缩小数组为空的位置。请发布logcatlogcat请。。。。