App is restarting while Relaunch from Home app Icon Android Signed Apk: -

i create android application 3 activities.

 <application         android:name=".myapplication"         android:allowbackup="true"         android:icon="@drawable/ic_launcher"         android:label="@string/app_name"         android:theme="@style/apptheme" >         <activity             android:name=".mainactivity"             android:label="@string/app_name"             android:windowsoftinputmode="statehidden"             android:screenorientation="landscape" >             <intent-filter>                 <action android:name="android.intent.action.main" />                 <category android:name="android.intent.category.default" />             </intent-filter>         </activity>         <activity             android:name=".loginactivity"             android:label="@string/app_name"             android:windowsoftinputmode="statehidden"             android:screenorientation="landscape" >             <intent-filter>                 <action android:name="android.intent.action.main" />                 <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>         <activity             android:name=".empselectionactivity"             android:label="@string/title_activity_emp_selection"             android:windowsoftinputmode="statehidden"             android:screenorientation="landscape" >             <intent-filter>                 <action android:name="android.intent.action.main" />                 <category android:name="android.intent.category.default" />             </intent-filter>         </activity>     </application> 

this working fine on android device (nexus 5) while debug application , run studio directly. when generate signed apk studio, apk not fetching preexisting activity while launching home.

that means: when launch application select main activity launcher activity (a login mechanism on there). press device home icon , click app icon device home. it's restarting again launcher activity instead of previous mainactivity. not happening while install apk without signed one.

please me, if have similar problem , found solution.