android otg swap with touch keyboard

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http://android.stackexchange.com – I'm new to android development. My first project needs a barcode scanning. I'm giving an option through OTG now. Now in my screen one more text box needs which takes input from keypress(for quantity). But in my android device keyboard is not getting enabled when i'm connected with OTG. Am I missing any device level configuration? Or How can i control the input way programatically(OTG barcode Scanner/Touch Pad). Thanks Binesh Nambiar C (HowTos)