May 28, 2004
Simple NSTableView Example
Finally finally finally I've figured out a way to add data to a table via a simple add form.
I built upon the Expenses example I coded previously.
Here's a brief run-down:
In Interface Builder:
1. I created a window like the one above.
2. I created a class called MyDataSource. This class had:
two outlets: amountField and categoryField
one function: addExpense()
3. I instantiated MyDataSource
4. In the Instances Pane, I made the following connections
From MyDataSource to NSTextField below Account: accountField
From MyDataSource to NSTextField below Category: categoryField
From MyDataSource to NSTableView: expenseTable
From NSTableView to MyDataSource: dataSource
From "Add Expense" button to MyDataSource: addExpense()
From File's Owner to MyDataSource: delegate
5. Create files for MyDataSource
In XCode:
/* MyDataSource */
import com.apple.cocoa.foundation.*;
import com.apple.cocoa.application.*;
public class MyDataSource {
public NSTextField categoryField;
public NSTextField amountField;
// expenseTable is the dataSource
public NSTableView expenseTable;
// holds expense values
NSMutableArray expenses;
// default constructor
public MyDataSource() {
super();
this.setExpenses(new NSMutableArray());
}
// METHOD: addExpense(Object sender)
// this function is called when "Add Expense" is clicked
public void addExpense(Object sender) {
Expense exp = new Expense();
String cat = categoryField.stringValue();
Double amt = new Double(amountField.doubleValue());
exp.setCategory(cat);
exp.setAmount(amt);
// add the newly created Expense object
// to expenses
expenses.addObject(exp);
// reload the table data
expenseTable.reloadData();
}
public NSArray getExpenses(){
return expenses;
}
public void setExpenses(NSMutableArray value){
this.expenses = value;
}
//implement abstract TableView methods
public int numberOfRowsInTableView(NSTableView tableView){
return expenses.count();
}
public Object tableViewObjectValueForLocation(
NSTableView tableView,
NSTableColumn tableColumn, int row){
String identifier = (String)tableColumn.identifier();
Expense expense = (Expense)expenses.objectAtIndex(row);
return (Object)expense.valueForKey(identifier);
}
public void tableViewSetObjectValueForLocation(
NSTableView tableView, Object object,
NSTableColumn tableColumn, int row){
String identifier = (String)tableColumn.identifier();
Expense expense = (Expense)expenses.objectAtIndex(row);
expense.takeValueForKey(object, identifier);
}
}
//
// Expense.java
// Expenses
//
// Created by Monica Shaw on Wed May 19 2004.
// Copyright (c) 2004 Red Dinosaur Productions. All rights reserved.
//
import com.apple.cocoa.foundation.*;
import com.apple.cocoa.application.*;
//the class must extend NSObject so we can use
//the method valueForKey()
public class Expense extends NSObject {
String date;
String category;
Double amount; //we need Objects
public Expense(){
super();
NSGregorianDate today = new NSGregorianDate();
//Format the date output
NSGregorianDateFormatter dateFormatter =
new NSGregorianDateFormatter("%b %d, %Y",false);
try{
this.setDate(dateFormatter.stringForObjectValue(today));
this.setCategory("Food");
this.setAmount(new Double(0));
}
catch (NSFormatter.FormattingException e){
System.err.println("Caught
NSFormatter.FormattingException: "+e.getMessage());
}
}
// get and set methods
public String getDate(){
return this.date;
}
public void setDate(String value){
this.date = value;
}
public String getCategory(){
return this.category;
}
public void setCategory(String value){
this.category = value;
}
public Double getAmount(){
return this.amount;
}
public void setAmount(Double value){
this.amount = value;
}
}