RuntimeException: Unable to instantiate activity componentInfo

Question

Good day! I'm trying to solve this problem for a week now that was not present before (That means to say that the program was working before).

Problem: My Login form's GUI won't load anymore.

Given: (LoginScreen Class-View)

public class LoginScreen extends Activity implements JPacketListener { 

private EditText editTextUsername;
private EditText editTextPassword;
private Button btnSubmit;
private boolean isReady = true;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.login_screen);
  loadUIReferences();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
  menu.add(1,1,1,"Change IP Connection");       
  return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {

  if (item.getTitle() == "Change IP Connection") {

    Intent intent = new Intent(LoginScreen.this,ChangeIp.class);
    startActivity(intent);
  }

  return super.onMenuItemSelected(featureId, item);
}

private void loadUIReferences() {

  editTextUsername = (EditText) this.findViewById(R.id.editTextUsername);
  editTextPassword = (EditText) this.findViewById(R.id.editTextPassword);
  btnSubmit = (Button) this.findViewById(R.id.btnSubmit);

  btnSubmit.setOnTouchListener(new OnTouchListener() {


@Override
public boolean onTouch(View v, MotionEvent event) {

if (!isReady) {
  return true;
}
  Toast.makeText(LoginScreen.this, "Loading...",Toast.LENGTH_SHORT).show();

  isReady = false;
try {
  Builder tpol = new ThreadPolicy.Builder().permitAll();
  StrictMode.setThreadPolicy(tpol.build());
  Toast.makeText(LoginScreen.this, "Connecting To Server...",Toast.LENGTH_LONG).show();
  JTCPConnectionClient client = new JTCPConnectionClient(Settings.IP, Settings.PORT);
  client.addListener(LoginScreen.this);
  client.send("Parameter too long, checkers, don't mind this");

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {

// TODO Auto-generated catch block
e.printStackTrace();
}

  return true;
}

});

}

@Override
  public void onPacketReceived(final JPacket arg0, JTCPConnection arg1) {

this.runOnUiThread(new Runnable() {

  @Override
    public void run() {
     try {

     String message = arg0.getMessage();
     isReady = true;
     String[] fields = message.split("\n");
Toast.makeText(LoginScreen.this, fields[1].split("=")[1],Toast.LENGTH_SHORT).show();
      if (fields[0].split("=")[1].equals("1")) {
    UserData.getInstance().setUsername(editTextUsername.getText().toString());
    Intent intent = new Intent(LoginScreen.this,SimpleCalendarViewActivity.class);
    startActivity(intent);
    finish();

}
} catch (Exception e) {

e.printStackTrace();
}
   }

 });

}

@Override
 public void onPacketSent(JPacket arg0, JTCPConnection arg1) {
 System.out.println("Packet Sent!");
}
}

My login_screen xml code:

<ScrollView 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"
tools:context=".MainActivity" >


<LinearLayout 
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentTop="true"
    android:orientation="vertical"              
    android:background="@drawable/background_lyceum_2" >
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:background="#CD6600"
    android:gravity="left"
    android:textColor="#FFFFFF"
    android:paddingBottom="20dp"
    android:text="My Application"
    android:textSize="11sp"
    />


<LinearLayout 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:weightSum="3"
    >
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />  
<TextView 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="USERNAME:"
    android:textSize="11sp"
    android:gravity="left"
    android:layout_weight="0.5"
    android:textColor="#000000"
    android:padding="5dp"
    android:layout_marginTop="20dp" />
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />  
    </LinearLayout>
<LinearLayout 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:weightSum="3"
    >
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />  
<EditText
    android:id="@+id/editTextUsername"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#FFFFFF"
    android:layout_weight="0.5"   
     />
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />
</LinearLayout>
<LinearLayout 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:weightSum="3"
    >
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />  
<TextView 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="PASSWORD:"
    android:textSize="12sp"
    android:layout_weight="0.5"
    android:gravity="left"
    android:textColor="#000000"
    android:padding="11dp"
    android:layout_marginTop="20dp" />
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />
</LinearLayout>
<LinearLayout 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:weightSum="3"
    >
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />  

    <EditText
    android:id="@+id/editTextPassword"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#FFFFFF"
    android:layout_weight="0.5"
    android:inputType="textPassword" />

<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />
</LinearLayout>
<LinearLayout 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:weightSum="3"
    >
    <TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />
<Button
    android:id="@+id/btnSubmit"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:background="#CD6600"
    android:gravity="center"
    android:padding="5dp"
    android:text="LOGIN"
    android:layout_weight="0.5"
    android:textColor="#FFFFFF"
    android:textSize="20sp"
    android:textStyle="bold" />
<TextView 
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:layout_weight="1.25"
    />
</LinearLayout>
</LinearLayout>

</ScrollView>

And finally, my AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.tsmirror"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="16" />

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.androidtutorial.app.view.LoginScreen"
        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.androidtutorial.app.view.SimpleCalendarViewActivity" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.ChangeIp" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.RecipientList" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.EventOptionShow" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.EventList" >
    </activity>
    <activity android:name="com.android.tsmirror.LoginScreen" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.CalendarOption" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.CalendarList" >
    </activity>
    <activity android:name="com.androidtutorial.app.view.EventOption" >
    </activity>
</application>

</manifest>

This is my Logcat output:

05-20 06:40:26.451: W/Trace(802): Unexpected value from nativeGetEnabledTags: 0
05-20 06:40:26.812: W/Trace(802): Unexpected value from nativeGetEnabledTags: 0
05-20 06:40:26.812: W/Trace(802): Unexpected value from nativeGetEnabledTags: 0
05-20 06:40:26.812: I/dalvikvm(802): Failed resolving Lcom/androidtutorial/app/view/LoginScreen; interface 577 'Lcom/jeshop/jtcpconnection/packet/JPacketListener;'
05-20 06:40:26.822: W/dalvikvm(802): Link of class 'Lcom/androidtutorial/app/view/LoginScreen;' failed
05-20 06:40:26.832: D/AndroidRuntime(802): Shutting down VM
05-20 06:40:26.832: W/dalvikvm(802): threadid=1: thread exiting with uncaught exception (group=0x40a70930)
05-20 06:40:26.852: E/AndroidRuntime(802): FATAL EXCEPTION: main
05-20 06:40:26.852: E/AndroidRuntime(802): java.lang.RuntimeException: Unable to instantiate     activity ComponentInfo{com.android.tsmirror/com.androidtutorial.app.view.LoginScreen}: java.lang.ClassNotFoundException: Didn't find class "com.androidtutorial.app.view.LoginScreen" on path: /data/app/com.android.tsmirror-1.apk
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.os.Handler.dispatchMessage(Handler.java:99)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.os.Looper.loop(Looper.java:137)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.ActivityThread.main(ActivityThread.java:5039)
05-20 06:40:26.852: E/AndroidRuntime(802):  at java.lang.reflect.Method.invokeNative(Native Method)
05-20 06:40:26.852: E/AndroidRuntime(802):  at java.lang.reflect.Method.invoke(Method.java:511)
05-20 06:40:26.852: E/AndroidRuntime(802):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
05-20 06:40:26.852: E/AndroidRuntime(802):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
05-20 06:40:26.852: E/AndroidRuntime(802):  at dalvik.system.NativeStart.main(Native Method)
05-20 06:40:26.852: E/AndroidRuntime(802): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.androidtutorial.app.view.LoginScreen" on path: /data/app/com.android.tsmirror-1.apk
05-20 06:40:26.852: E/AndroidRuntime(802):  at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
05-20 06:40:26.852: E/AndroidRuntime(802):  at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
05-20 06:40:26.852: E/AndroidRuntime(802):  at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
05-20 06:40:26.852: E/AndroidRuntime(802):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
05-20 06:40:26.852: E/AndroidRuntime(802):  ... 11 more

Note: Whenever I remove the code 'implements JPacketListener' after the 'extends Activity' and also remove it's methods (onPacketReceived/onPacketSent), LoginScreen GUI loads on my emulator.

Any help would be appreciated! Thank you in advance!

Answer 1

Failed resolving Lcom/androidtutorial/app/view/LoginScreen; interface 577 'Lcom/jeshop/jtcpconnection/packet/JPacketListener;'

This is the reason for the ClassNotFoundException . There's an unresolved interface and the class loader rejects the class.

Have you included the library that contains JPacketListener in your project?