[英]passing a parameter from MainActivity.java into my SQLiteOpenHelper class
I have set up my SQLiteOpenHelper class and all working ok to retrieve all data in the sqLite database. 我已经设置了SQLiteOpenHelper类,并且一切正常,可以检索sqLite数据库中的所有数据。 I now want tp pass a parameter from mainActivity into my SQLiteOpenHelper class to find certain records.
我现在希望tp从mainActivity传递一个参数到我的SQLiteOpenHelper类中以查找某些记录。 User will enter search criteria into a field and i want to pass that user entry to be searched.
用户将在字段中输入搜索条件,而我想通过该用户条目进行搜索。 Currently i have hard coded to search for category 161 but this is where i want to be able to use the parameter passed by the user.
目前,我已经硬编码搜索类别161,但这是我希望能够使用用户传递的参数的地方。 I have put my SQLiteOpenerHelper code and my mainActivty code below.
我在下面放置了SQLiteOpenerHelper代码和mainActivty代码。 I have tried passing a parameter into the getAllUsers() in mainActivity file but Android will not accept parameters.
我尝试过将参数传递到mainActivity文件的getAllUsers()中,但Android将不接受参数。 Can someone please help in showing me what i need to do to pass the parameter i need into the sqLite query
有人可以帮我看看我需要怎么做才能将我需要的参数传递给sqLite查询
SQLiteOpenHelper class SQLiteOpenHelper类
public ArrayList<HashMap<String, String>> getAllUsers() {
ArrayList<HashMap<String, String>> usersList;
usersList = new ArrayList<HashMap<String, String>>();
String[] columns = {"id", "company", "firstname", "lastname", "category"};
SQLiteDatabase database = this.getWritableDatabase();
Cursor cursor = database.query("members", columns, "category = 161", null, null, null, "company");
if (cursor.moveToFirst()) {
do {
HashMap<String, String> map = new HashMap<String, String>();
map.put("id", cursor.getString(0));
map.put("company", cursor.getString(1));
map.put("firstname", cursor.getString(2));
map.put("lastname", cursor.getString(3));
map.put("category", cursor.getString(4));
usersList.add(map);
} while (cursor.moveToNext());
}
database.close();
return usersList;
}
mainActivity.java mainActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Get User records from SQLite DB
ArrayList<HashMap<String, String>> userList = controller.getAllUsers();
I don't see a problem here. 我在这里没有问题。 Just define the method as:
只需将方法定义为:
public ArrayList < HashMap< String, String >> getAllUsers(int category){
//
}
Then instead of "category = 161"
, use "category = " + category
as the third parameter in query. 然后,使用
"category = " + category
作为查询中的第三个参数,而不是"category = 161"
。
And call it from main activity as: 并从主要活动中将其称为:
ArrayList < HashMap< String , String>> userList = controller.getAllUsers(161);
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