Four ways to start activity in Android

There are four modes of activity in Android: Standard, Singletop, Singletask, SingleInstance.

Standard

This is the activity by default, if you do not specify how to start the activity, the default is to start with standard. Each time the activity is started, a new activity object is generated regardless of whether or not there is a corresponding activity in the stack.

Singletop

If the corresponding activity is at the top of the stack, the instance is used directly or a new activity instance is generated

Singletask

If there is a corresponding activity instance in the stack, the activity of the activity instance is all out of the stack, making the activity instance the top of the Stack object, and then directly using the activity instance to be displayed on the screen.

SingleInstance

Android will enable a new station structure to hold the current activity,

http://blog.csdn.net/liuhe688/article/details/6754323