Android: How to integrate External BarCode Scanner device connected via USB to Android Application

i think every single barcode scanner have integration support for android, but what i need is to give common support for all or more external barcode scanners.

It sounds like you are looking for something that you yourself admit doesn't exist. There isn't a common standard that ALL scanners implement for proper Android integration. That said, here's how you can achieve your two goals

Any Brand: Most barcode scanners support HID mode, which is basically just connecting as a keyboard; this is how practically all USB scanners work. Using HID mode the scanner will "type" the barcode wherever the cursor is located, which doesn't give you much control.

End event: Again, most barcode scanners can be configured to append a trailing character. Usually it defaults to a carriage return or tab. In your activity or view you can set an onKeyListener and in that listener you watch for the KEY_DOWN event of your trailing character which indicates the end of a scan.

Using HID and trailing character detection you will be able to support most wired and wireless scanners