Setting the dialog cancelable to be false is enough, and either you touch outside of the alert dialog or click the back button will make the alert dialog disappear. So use this one:
setCancelable(false)
And the other function is not necessary anymore:
dialog.setCanceledOnTouchOutside(false);
If you are creating a temporary dialog and wondering there to put this line of code, here is an example:
new AlertDialog.Builder(this)
.setTitle("Trial Version")
.setCancelable(false)
.setMessage("You are using trial version!")
.setIcon(R.drawable.time_left)
.setPositiveButton(android.R.string.yes, null).show();