android - Method to excute query and return results -

app won't run - trying execute query print value

method:

public cursor trying(string vg){     string q="select quantity " + table_contacts +  " name=" + vg;     sqlitedatabase db = this.getreadabledatabase();     cursor  cursor = db.rawquery(q,null);              if (cursor != null) {                 cursor.movetofirst();             }             return cursor;     } 

calling method main

cursor wow = db.trying("gold"); text = (textview) findviewbyid(r.id.textview13); text.settext((charsequence) (wow)); 

at first. since directly adding trying variables statement, variable must wrapped single quotes or it's interpeted column.

"select quantity " + table_contacts +  " name= '" + vg + "'"; 

and second "big" problem, here:

text.settext((charsequence) (wow)); 

here trying cast cursor charsequence it's not possible. if want retrieve data cursor have use 1 getters methods of cursor class in case getstring() method:

string quantity = wow.getstring(0); // returns quantity cursor text.settext(quantity); 

now should works.

recommendation:

i suggest usage of parametrized statements use placeholders in queries. provide more safer way adding , retrieving data / database.

let's rewrite code:

string q = "select quantity " + table_contacts + " name = ?"; sqlitedatabase db = this.getreadabledatabase(); cursor  cursor = db.rawquery(q, new string[] {vg}); 

it works simply. placeholder ? replaced string value.