Intents, in general, are used for navigating among various activities within the same application, but note, is not limited to one single application, i.e., they can be utilized from moving from one application to another as well.

An intent filter declares the capabilities of its parent component: what an activity or service can do and what types of broadcasts a receiver can handle. It opens the component to receiving intents of the advertised type while filtering out those that aren't meaningful for the component.

As already mentioned above explicit intents are those in which the user has a clear vision and knows exactly which activity can handle the requests. Implicit intents do not name a specific component like explicit intent, instead declare general action to perform, which allows a component from another app to handle.

ACTION_VIEW is the action on Intent. public static final String ACTION_VIEW. Since: API Level 1 Activity Action: Display the data to the user. This is the most common action performed on data -- it is the generic action you can use on a piece of data to get the most reasonable thing to occur.