Question

在我的活动中，我有editText的（用户名，名字，姓氏和电子邮件地址）。当用户输入现有用户名时，他可以通过单击搜索按钮进行搜索，并且用户拥有的数据将显示在editText中。

MainActivity.java

btn_Search.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View arg0) {
        String searchableUser = txt_User.getText().toString();

        ConsUserRegistration consUserRegistration = db.searchUser(searchableUser);

        String searchUser = consUserRegistration.getUser().toString();
        String searchFirst = consUserRegistration.getFirstName().toString();
        String searchLast = consUserRegistration.getLastName().toString();
        String searchEmail = consUserRegistration.getEmail().toString();

        txt_User.setText(searchUser);
        txt_First.setText(searchFirst);
        txt_Last.setText(searchLast);
        txt_Email.setText(searchEmail);             
    }
});

DatabaseHandler.java

public ConsUserRegistration searchUser(String username){

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.query(Constants.TABLE_USER, new String[] {Constants.KEY_USER, Constants.KEY_FIRST, 
            Constants.KEY_LAST, Constants.KEY_EMAIL}, Constants.KEY_USER + " =? ", 
            new String[] { String.valueOf(username) }, null, null, null);
    if (cursor != null)
        cursor.moveToFirst();

    ConsUserRegistration search = new ConsUserRegistration (cursor.getString(0), cursor.getString(1), cursor.getString(2), cursor.getString(3));

    return search;

}

但是当用户单击搜索按钮并且没有输入用户名EditText中的任何字符时，我在DatabaseHandler中遇到CursorIndexOutOfBoundsException错误：ConsUserRegistration search = new ConsUserRegistration（cursor.getString（0 ），cursor.getString（1），cursor.getString（2），cursor.getString（3））;

此外，我无法从数据库中检索数据，因为它正在崩溃。

Answer 1

更改

db.searchUser(searchableUser);
ConsUserRegistration consUserRegistration = new ConsUserRegistration();

到

ConsUserRegistration consUserRegistration = db.searchUser(searchableUser);

Answer 2

按钮按钮_搜索（按钮）findViewById（r.I'd.itsIdInYourXml）;

按钮可能需要声明或定义，还需要查看整个代码

搜索记录并从Android中的数据库中检索它

2 个答案: