java - how to start new activity in android -

i want start new activity called counter when button clicked, got error activity not found...so wrong in code:

t = new thread(){              public void run(){                  try{                      sleep(5000);                 }                 catch (interruptedexception e){                      e.printstacktrace();                 }                 finally{                      intent counter = new intent("com.example.test.counter");                     startactivity(counter);                 }             }         };          test.setonclicklistener(new onclicklistener() {              @override             public void onclick(view v) {                  t.run();             }         }); 

this manifest file :

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.example.test"     android:versioncode="1"     android:versionname="1.0" >      <uses-sdk         android:minsdkversion="8"         android:targetsdkversion="17" />      <application         android:allowbackup="true"         android:icon="@drawable/ic_launcher"         android:label="@string/app_name"         android:theme="@style/apptheme" >         <activity             android:name="com.example.test.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>         <activity             android:name="com.example.test.counter"             android:label="@string/title_activity_counter" >         </activity>     </application>  </manifest> 

change this

   intent counter = new intent("com.example.test.counter");    startactivity(counter); 

this called implicit intent , needs intent filter

to

  intent counter = new intent(mainactivity.this,counter.class);   startactivity(counter); 

this called explicit intent , there no need intent filter

you should use explicit intent coz have

   <activity         android:name="com.example.test.counter"         android:label="@string/title_activity_counter" >     </activity> 

quoting docs

explicit intents specify component start name (the fully-qualified class name). you'll typically use explicit intent start component in own app, because know class name of activity or service want start. example, start new activity in response user action or start service download file in background.

note: explicit intent delivered target, regardless of intent filters component declares.

edit:

you should call start() on thread not run