Question

Im trying to add an object to NSMutableArray it seems to get duplicated.

@interface TestObject : NSObject {
    double a_actual;
    double a_target;
}
@property(assign) double a_actual;
@property(assign) double a_target;

Create some pointers:

NSMutableArray * myTestObjectArray;
TestObject * myTestObject;

Init them:

myTestObjectArray = [[NSMutableArray alloc] init];
myTestObject = [[TestObject alloc] init];

I add value to the object and add it to the array:

[myTestObject setA_actual:234];
[myJointDataArray insertObject:myTestObject];

I add different values to each object, but i do not necessarily fill all the variables out.
When i print each object out i have the same (last) value duplicated in all objects for some reason.

Printing the array shows that all objects are the same:

 Array: (
     "<TestObject: 0x6b9b400>",
     "<TestObject: 0x6b9b400>",
     "<TestObject: 0x6b9b400>",
     "<TestObject: 0x6b9b400>",
     "<TestObject: 0x6b9b400>",
     "<TestObject: 0x6b9b400>" )

Should i alloc a new object of TestObject everytime i want to work with a new?

Answer 1

Should i alloc a new object of TestObject everytime i want to work with a new?

Yes. If you don’t allocate a new object, you’re just working with the same object over and over again. It appears you want multiple, distinct objects, so allocate a new instance for each one.