如何從非活動接收信息到活動類

我必須在我的android項目中上課，第一類是Main Activity，它是extend Activity，另一個類是MSSQLConnect，它是一個簡單的類，用於從數據庫獲取數據並返回它作爲數組列表如何從非活動接收信息到活動類

我用這個方法調用MSSQLConnect類，但它不工作：

MainActivity類別

public class MainActivity extends Activity { 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 


MSSQLConnect cdb = new MSSQLConnect("id", "mytable", "", ""); 
Toast.makeText(this, cdb.getdata("getApplicationContext()"), Toast.LENGTH_SHORT).show(); }}

MSSQLConnect類：

public class MSSQLConnect extends ContextWrapper { 


private final String table; 
private final String columns; 
private final String whereColumn; 
private final String equalsEntry; 


public MSSQLConnect (Context context, String columns, String table, String whereColumn, String equalsEntry) { 
    super(context); 
    this.table = table; 
    this.columns = columns; 
    this.whereColumn = whereColumn; 
    this.equalsEntry = equalsEntry; 

} 

static String JDBC_DRIVER = "net.sourceforge.jtds.jdbc.Driver"; 
static String DB_URL ="jdbc:jtds:sqlserver://xxx.xxx.x.x:xxx;DatabaseName=xxxx"; 

// Database credentials 
static String USER = "xxxxx"; 
static String PASS = "xxxxx"; 

public ArrayList<ArrayList<String>> ourQuerryMethod() { 
    Connection conn = null; 
    Statement stmt = null; 

    String data[][] = null; 
    ArrayList<ArrayList<String>> setData = new ArrayList<ArrayList<String>>(); 
    try { 
     Class.forName(getJDBC_DRIVER()); 
     conn = DriverManager.getConnection(getDB_URL(), getUSER(), getPASS()); 
     stmt = conn.createStatement(); 
     String sql; 
     if(whereColumn.equals("") && equalsEntry.equals("")) 
     { 
      sql = "SELECT " + (columns) + " FROM " + (table); 
     } 
     else 
      sql = "SELECT " + (columns) + " FROM " + (table) + " WHERE "+ (whereColumn) +" = "+ (equalsEntry) +""; 

     ResultSet rs; 
     rs = stmt.executeQuery(sql); 

      int nc = 1; 
      ArrayList<String> columns = new ArrayList<String>(); 
      int rowCount =0; 
      while(rs.next()) // loop rows 
      { 

       rowCount++; 
       if(rowCount == 1) 
       { 
        while(true){ //loop columns 
         try { 
          columns.add(rs.getString(nc)); 
         } catch (Exception e) { 
          // TODO: handle exception 

          break; 
         } 
         nc++; 
        } 
       } 

       int rrowrr = 0; 
       for(int i=1;i<nc;i++) 
       { 
        rrowrr++; 
        if(rrowrr == 1) 
        { 
         setData.add(new ArrayList<String>()); 
        } 
        setData.get(rs.getRow()-1).add(rs.getString(i)); 
       } 

      } 
     rs.close(); 
    }catch (SQLException se) { 
     // Handle errors for JDBC 
     se.printStackTrace(); 
     Log.d("DBError1", se.getMessage()); 
    } catch (Exception e) { 
     // Handle errors for Class.forName 
     e.printStackTrace(); 
     Log.d("DBError2", e.getMessage()); 

    } finally { 
     // finally block used to close resources 
     try { 
      if (stmt != null) 
       conn.close(); 
     } catch (SQLException se) { 
      Log.d("DBError3", se.getMessage()); 

     } 
     try { 
      if (conn != null) 
       conn.close(); 
     } catch (SQLException se) { 
      se.printStackTrace(); 
      Log.d("DBError4", se.getMessage()); 

     } // end finally try 
    } // end try 
    return setData; 
} // end main 

public static String getJDBC_DRIVER() { 
    return JDBC_DRIVER; 
} 
public static void setJDBC_DRIVER(String aJDBC_DRIVER) { 
    JDBC_DRIVER = aJDBC_DRIVER; 
} 

public static String getDB_URL() { 
    return DB_URL; 
} 


public static void setDB_URL(String aDB_URL) { 
    DB_URL = aDB_URL; 
} 


public static String getUSER() { 
    return USER; 
} 

public static void setUSER(String aUSER) { 
    USER = aUSER; 
} 
public static String getPASS() { 
    return PASS; 
} 

public static void setPASS(String aPASS) { 
    PASS = aPASS; 
}}

來源

2015-05-19 user1139589

使用此

public class MainActivity extends Activity { 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
MSSQLConnect connect=new MSSQLConnect(); 
ArrayList<String> list = new ArrayList<String>(); 
list=connect.ourQuerryMethod(); 

ConnectDB cdb = new ConnectDB("id", "mytable", "", ""); 
Toast.makeText(this, cdb.getdata("getApplicationContext()"), Toast.LENGTH_SHORT).show(); }}

來源

2015-05-19 18:14:56

MSSQLConnect類和ConnectDB類是相同的。 – user1139589

然後使用上面的方法 –

複製此代碼並運行此 –

JDBC爲Android ???你瘋了嗎？我建議你使用php頁面進行sql查詢並使用asynctask在json中解析它，但是如果你喜歡JDBC，我會問你幾個問題，爲什麼MSSQLConnect類會重命名爲ConnectDB？和MSSQLConnect生成器有5個參數，但你有4個參數創建對象？

來源

2015-05-19 18:21:42

其實我試了很多使用c＃但它不適合我，當我在java項目中使用JDBC它工作正常。 – user1139589

好，但構造函數ispublic MSSQLConnect（上下文上下文，字符串列，字符串表，字符串whereColumn，字符串equalsEntry），並且您創建了具有4個元素的MSSQL對象...檢查它並嘗試 –

如何從非活動接收信息到活動類

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