Android show digits keypad on activity start

As stated in the title, how do I call the digits keypad on activity start? Right now I have this:

InputMethodManager imm = (InputMethodManager)getSystemServ开发者_Python百科ice(Context.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);

in OnCreate. But this is just a normal full keyboard with letters.

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this was my aproach.

To show it

InputMethodManager lIMManager

lIMManager = (InputMethodManager) getSystemService(this.INPUT_METHOD_SERVICE);
lIMManager.getInputMethodList();
lIMManager.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);

To hide it

mIMManager.hideSoftInputFromWindow(txtPin.getWindowToken(), 0);

The down side is that you have to close it by hand( it wont even close if you close the app) Hope this helps! Regards