What is the use of plist?

In the context of iPhone development, Property Lists are a key-value store that your application can use to save and retrieve persistent data.

All iPhone applications have at least one of these by default, the Information Property List:

The information property list is a file named Info.plist that is included with every iPhone application project created by Xcode. It is a property list whose key-value pairs specify essential runtime-configuration information for the application. The elements of the information property list are organized in a hierarchy in which each node is an entity such as an array, dictionary, string, or other scalar type.

It's been a long time since I've looked at them, but plist is a short-form of "properties list" and can be used to store application configuration settings that need to persist between instances of an application's execution. Could be similar to a .properties file (I see those a lot on Java projects).

PList means PropertyList It is XML file format It is mainly user for store and reterve the data It can store the key-value pair

Plist are XML files in a specific format. Prior to XML, they had a custom format now called 'old plist'. (You almost never see that anymore save in legacy code.)

Foundations collection classes automatically generate XML files in the plist format when you use their serialization methods to write them to disk. They also automatically read them back. You can also write your own serializers for your own custom objects. This allows you to persistently store complex objects in a robust, human readable format.

One use for plist for programmers is that it is easier to use the plist editor to input and manage a lot of data than it is to try and code it. For example, if you have an class that requires setting a large number of ivars, you can create a plist, read it into an NSArray or NSDictionary and then initialize the instance by passing it the dictionary.

I use this technique when I have to use a large number of paths to draw complex objects. You define the path in the plist file instead of the code and edit the path in the plist editor.

It's also a handy way to create a large amount of detailed test data.