alertDialog.getWindow().clearFlags(
WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);
去除flag
AlertDialog alertDialog = new AlertDialog.Builder(
MeActivity.this).create();
alertDialog.show();
Window window = alertDialog.getWindow();
alertDialog.getWindow().clearFlags(
WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);
window.setContentView(R.layout.change_psw);

            EditText etOld = (EditText) window.findViewById(R.id.pwd_0);