How to handle unrecognized selector sent to instance?

The “Unrecognized selector sent to instance” is an annoying error in Xcode….Fixing «Unrecognized Selector Sent To Instance»

1. First, check that the selector is called on the right object. The function name should exist on that object.
2. Then, check the function name.
3. Then, check the function parameters.

What is selector method?

A selector is an identifier which represents the name of a method. It is not related to any specific class or method, and can be used to describe a method of any class, whether it is a class or instance method. Simply, a selector is like a key in a dictionary.

What is a selector in Java?

In Java NIO the selector is a multiplexor of selectable channels, which is used as a special type of channel that can be put into non-blocking mode. It can examine one or more NIO Channel’s and determines which channel is ready for communication i.e. reading or writing.

How do you write a class selector in CSS?

To select elements with a specific class, write a period (.) character, followed by the name of the class. You can also specify that only specific HTML elements should be affected by a class. To do this, start with the element name, then write the period (.)

How do you create a selector in Java?

A selector may be created by invoking the open method of this class, which will use the system’s default selector provider to create a new selector. A selector may also be created by invoking the openSelector method of a custom selector provider. A selector remains open until it is closed via its close method.

What is the example of class selector?

A class selector looks just like an element selector, but instead of using names that are tied to the names of HTML elements, you make up the name and then you prefix it with a dot (.). For instance: . red { }