android - MonkeyRunner unable to use startActivity -

the following androimanifest.xml:

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.example.helloworld"     android:versioncode="1"     android:versionname="1.0" >      <uses-sdk         android:minsdkversion="8"         android:targetsdkversion="21" />      <application         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" >             <intent-filter>                 <action android:name="android.intent.action.main" />                  <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>     </application>  </manifest> 

i want launch app using monkeyrunner when give command

device.startactivity(component='com.exmaple.helloworld/com.example.helloworld.mainactivity') 

it doesn't start app. missing anything. read issues using monkeyrunner startactivity still didn't work.

device.startactivity(component='com.exmaple.helloworld/com.example.helloworld.mainactivity')

have tried fixing typo (exmaple instead of example) ?

device.startactivity(component='com.example.helloworld/com.example.helloworld.mainactivity')