android - Difficulty in hint display for edit text -

hi used hint edit text shows perfect when not used gravity of edit text center

but once when used android:gravity="center" doesnot showing hint know why?

here code

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:layout_alignparentleft="true"     android:layout_alignparenttop="true" >      <linearlayout         android:id="@+id/linearlayout"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignparentleft="true"         android:layout_alignparentright="true"         android:orientation="vertical" >          <include layout="@layout/header" />     </linearlayout>      <relativelayout         android:id="@+id/rl"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:background="@color/maroon"         android:orientation="vertical" >          <relativelayout             android:id="@+id/login_rllogin"             android:layout_width="match_parent"             android:layout_height="200dp"             android:layout_centerinparent="true"             android:visibility="gone" >              <edittext                 android:id="@+id/login_et_password"                 android:layout_width="match_parent"                 android:layout_height="40dp"                 android:layout_alignparentleft="true"                 android:layout_alignparentright="true"                 android:layout_centervertical="true"                 android:layout_marginleft="10dp"                 android:layout_marginright="10dp"                 android:background="@color/white"                 android:gravity="center"                 android:hint="@string/login_hint_enterpassword"                 android:inputtype="numberpassword"                 android:maxlength="4"                 android:maxlines="1"                 android:textcolor="@color/black"                 android:textcolorhint="@color/dark_gray" />              <button                 android:id="@+id/login_btn_login"                 android:layout_width="match_parent"                 android:layout_height="45dp"                 android:layout_alignleft="@+id/login_et_password"                 android:layout_alignright="@+id/login_et_password"                 android:layout_below="@+id/login_et_password"                 android:layout_margintop="5dp"                 android:background="@color/fent_orange"                 android:text="@string/login_btn_caption"                 android:textappearance="?android:attr/textappearancelarge"                 android:textcolor="@color/black"                 android:textstyle="bold" />         </relativelayout>          <relativelayout             android:id="@+id/login_rlreg"             android:layout_width="match_parent"             android:layout_height="150dp"             android:layout_centerinparent="true"             android:visibility="visible" >              <edittext                 android:id="@+id/login_et_repassword"                 android:layout_width="match_parent"                 android:layout_height="40dp"                 android:layout_alignparentleft="true"                 android:layout_alignparentright="true"                 android:layout_centervertical="true"                 android:layout_marginleft="10dp"                 android:layout_marginright="10dp"                 android:layout_margintop="1dp"                 android:background="@color/white"                 android:gravity="center"                 android:hint="@string/login_hint_reenterpassword"                 android:inputtype="numberpassword"                 android:maxlength="4"                 android:maxlines="1"                 android:textcolor="@color/black"                 android:textcolorhint="@color/dark_gray" />              <button                 android:id="@+id/login_btn_submit"                 android:layout_width="match_parent"                 android:layout_height="45dp"                 android:layout_alignleft="@+id/login_et_repassword"                 android:layout_alignright="@+id/login_et_repassword"                 android:layout_below="@+id/login_et_repassword"                 android:layout_margintop="5dp"                 android:background="@color/fent_orange"                 android:text="@string/submit_btn_caption"                 android:textappearance="?android:attr/textappearancelarge"                 android:textcolor="@color/black"                 android:textstyle="bold" />              <edittext                 android:id="@+id/login_et_choosepassword"                 android:layout_width="match_parent"                 android:layout_height="40dp"                 android:layout_above="@+id/login_et_repassword"                 android:layout_alignparentleft="true"                 android:layout_alignparentright="true"                 android:layout_marginleft="10dp"                 android:layout_marginright="10dp"                 android:background="@color/white"                 android:gravity="center"                 android:hint="@string/login_hint_choosepassword"                 android:inputtype="numberpassword"                 android:maxlength="4"                 android:maxlines="1"                 android:textcolor="@color/black"                 android:textcolorhint="@color/dark_gray" >                  <requestfocus />             </edittext>         </relativelayout>          <textview             android:id="@+id/tvapptitle"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_above="@+id/login_rlreg"             android:layout_alignparentleft="true"             android:layout_alignparentright="true"             android:layout_alignparenttop="true"             android:gravity="center"             android:text="@string/app_name"             android:textappearance="?android:attr/textappearancelarge"             android:textsize="26sp"             android:textstyle="bold" />          <relativelayout             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_alignparentbottom="true"             android:layout_alignparentleft="true"             android:layout_alignparentright="true"             android:layout_below="@+id/textview1"             android:background="@color/white" >              <textview                 android:id="@+id/textview3"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_centerinparent="true"                 android:background="@drawable/ztam"                 android:textappearance="?android:attr/textappearancelarge" />         </relativelayout>          <textview             android:id="@+id/textview1"             android:layout_width="wrap_content"             android:layout_height="7dp"             android:layout_alignparentleft="true"             android:layout_alignparentright="true"             android:layout_below="@+id/login_rlreg"             android:layout_margintop="70dp"             android:background="@color/fent_orange"             android:textappearance="?android:attr/textappearancemedium" />     </relativelayout>  </relativelayout>