Panda Helper 
Activity
The Activity class is a crucial component of an Android app. An activity provides the window in which the app draws its UI. Most apps contain multiple screens, which means they comprise multiple activities. Typically, one activity in an app is specified as the main activity, which is the first screen to appear when the user launches the app. Those activities are shown in Launcher applications.Activity Manager provides list of all activities of installed application and ability to run them.
Activities can be divided into 3 groups:
1. Exported activities
Can be launched by anybody.
2. Non-Exported activities
Can be launched inside application or using ROOT. Those activities marked with red color in Activity Manager application.
3. Activities with custom permission
Can be exported or non-exported. A parent activity cannot launch a child activity unless both activities have the same permissions in their manifest. Activity Manager does not support those activities. If you try to run them you will see an error message.
