create instance of class with NSString

Question

I need to create a new instance of an object every time a method is called. So I need to create a loop that checks for the existence of a variable counter like newInstance1 and if it is found create newInstance2. How can you create a class from an nsstring? The goal is to create views that I can drag around on a grid that have represented objects in them. Here is that method that creates the new object and view

//method creates view with new fixtureIcon
- (IBAction)makeView:(id)sender {


    rectString = [NSString stringWithFormat:@"0,120,%f,%f", pm.fixWidth, pm.fixHeight];
    _try = [[fixtureIcon alloc]init];

    _try.fixImg = pm.fixImage;
    _try.name = pm.name;
    [fixController addObject:_try];     




    _testBox = [[addObjectView alloc]initWithFrame:NSRectFromString(rectString)];



    NSImageView *iconView = [[NSImageView alloc]initWithFrame:NSMakeRect(0, 0, 75, 75)];
    testView1Controller = [[NSViewController alloc]init];
    testView1Controller.view = _testBox;


    [_testBox setWantsLayer:YES];




    _testBox.layer.masksToBounds = YES;
    _testBox.layer.cornerRadius = 2.0;
    _testBox.layer.borderWidth = 2;
    _testBox.layer.borderColor = [[NSColor darkGrayColor]CGColor];

    //this tells the window to add our subview testbox to it's contentview

    [testView1Controller setView:_testBox];

    [testView1Controller bind:@"representedObject" toObject:fixController withKeyPath:@"content" options:nil];

    [mainWin addSubview:_testBox];
    NSTextField *obLabel = [[NSTextField alloc]initWithFrame:CGRectMake(0, 0, 50, 40)];
    [obLabel bind:@"value" toObject:testView1Controller withKeyPath:@"representedObject.type" options:nil];
    [obLabel setBackgroundColor:[NSColor clearColor]];
    [obLabel setSelectable:false];
    [obLabel setEditable:false];
    [obLabel setBackgroundColor:[NSColor grayColor]];
    [obLabel setBordered:false];
    [obLabel setTextColor:[NSColor whiteColor]];
    [iconView bind:@"value" toObject:testView1Controller withKeyPath:@"representedObject.fixImg" options:nil];
    //[_testBox addSubview:obLabel];
    [_testBox addSubview:iconView];

The reason I need new instances is so I don't overwrite the property values and lose my representedObject data for each view.

Consider using an NSMutableArray and doing addObject on it instead. — user467105
– user467105, Commented Feb 18, 2014 at 1:57
@Anna I am still going to have to change the initialized name of the instance that way.Right? — tyler_nichol
– tyler_nichol, Commented Feb 18, 2014 at 2:55
It might help if you explain in your question what you're trying to accomplish or what problem you're trying to solve by this. What I mean is: Declare an NSMutableArray named say myInstances. Create and add your objects to it. You can then access them by index (eg. [myInstances objectAtIndex:2]). — user467105
– user467105, Commented Feb 18, 2014 at 3:05
@Anna - I am creating a new instance of an object to be represented by a view controller. This is done dynamically. The user clicks a button that creates the new object. — tyler_nichol
– tyler_nichol, Commented Feb 18, 2014 at 3:11
@tyler_nichol. Please share some code, it might help us all understand what you're trying to do. From your comments and question is not clear at all. — Aaron
– Aaron, Commented Feb 18, 2014 at 4:03

Aaron · Accepted Answer · 2014-02-18 01:55:31Z

4

id object = [[NSClassFromString(@"NameofClass") alloc] init];

answered Feb 18, 2014 at 1:55

Aaron

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2 Comments

tyler_nichol Over a year ago

create instance of class not class name itself. Like someclass *stringforclassinstance = [someclass alloc]init];

Aaron Over a year ago

This code creates an instance of a class of type NameofClass. Also, the subject line of your question reads: "create instance of class with NSString." This is what this code does. If you mean something different, please rephrase or edit your question.

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