Incorrect decrement of the reference count of an object that is not owned at this point by the calle

Incorrect decrement of the reference count of an object that is not owned at this point by the caller

这种问题一般就是变量申请了内存并初始化了，但没有使用此变量，接着将此变量又重新赋值。如下：

NSString *imageString = [[NSString alloc] init];
imageString = @"HResout";

Problem with stringByAppendingString and retain count

I need to concatenate some strings.

NSString * sportName = [[NSString alloc ]initWithString:@""]; sportName = [sportName stringByAppendingString:[someObject getString]]; // can be more stringByAppendingString ... [sportName release]; 

But something strange for me give the 'build and analyze' command:

on string:

sportName = [sportName stringByAppendingString:[someObject getString]]; 

the error:Method returns an Objective-C object with a +0 retain count (non-owning reference)

on string:

[sportName release]; 

the error: Incorrect decrement of the reference count of an object that is not owned at this point by the caller

I am using it for filling my TableView and it is crashed after loading :(.

NSString * sportName = [[NSString alloc ]initWithString:@""]; sportName = [sportName stringByAppendingString:[someObject getString]]; 

In 2nd line you are getting a new string which is assigned back to spotName. So the alloced string in first line is leaked. I don't understand why you need to append in an empty string. Appending to @"" is practically of no effect. And if you have some non-empty string then you can create that as autoreleased string instead of alloc. Like this:

// create an autoreleased string NSString * sportName = @"my_string"; // this will return a new string which is also autoreleased sportName = [sportName stringByAppendingString:[someObject getString]]; // all subsequent call to stringByAppendingString will return autoreleased string //so no need to release spotName 

And if you need to retain spotName then you can retain that or use a property.