Fatal Error: Class cannot be cast to another class on button click

Question

I'm trying to use the Android Skype SDK sample code in my project and I'm getting an error saying Could not execute method OnClick. SkypeActivity.class cannot be cast to S4BDemoApplication.class.

My guess is this part of code in my S4BDemoApplication.class:

@Override
protected void attachBaseContext(Context base) {
     super.attachBaseContext(base);
     MultiDex.install(this);
}

The line MultiDex.install(this) might be causing the issue as I haven't included any dexOptions in my gradle.

I actually did have them but when I try to run it, I get an error saying

no such property preDexLibraries So I had to comment them out in my gradle and it worked fine.

Do you think this is the reason for the error? Is there a workaround for this?

My gradle file

apply plugin: 'com.android.application'

def ROOTDIR     = file("..").absolutePath

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"
    useLibrary 'org.apache.http.legacy'


defaultConfig {
    applicationId "it.moondroid.chatbot"
    minSdkVersion 17
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
    multiDexEnabled true
}

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_7
    targetCompatibility JavaVersion.VERSION_1_7
}

buildTypes {
    debug {
        minifyEnabled false
        debuggable true
        jniDebuggable true
    }

    release {
        debuggable true
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }

    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/MSFTSIG.RSA'
        exclude 'META-INF/BCKEY.DSA'
        exclude 'META-INF/BCKEY.SF'
        exclude 'META-INF/MSFTSIG.SF'
    }

    dexOptions {
      //  preDexLibraries=false
      //  jumboMode = true
      //  javaMaxHeapSize "4g"
    }
}

configurations {
    all*. exclude group: 'com.android.support', module: 'support-v4'
    all*. exclude group: 'com.android.support', module: 'support-annotations'
}

productFlavors {
}
}

dependencies {

compile 'com.android.support:multidex:1.0.1'
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile files('libs/sanmoku-0.0.5.jar')
compile files('libs/joda-time-2.1.jar')
compile(name: "libucmp", ext: 'aar')
compile(name: "platform", ext: 'aar')
compile(name: "injector", ext: 'aar')
compile(name: "SkypeForBusiness", ext: 'aar')
compile(name: "ucmp-enums", ext: 'aar')
compile(name: "TelemetryClient2", ext: 'aar')
compile(name: "TelemetryService", ext: 'aar')
compile(name: "android-database-sqlcipher", ext: 'aar')
compile 'com.android.support:appcompat-v7:23.0.1'
compile 'com.android.support:design:23.1.1'
compile 'com.android.support:recyclerview-v7:23.0.1'
compile 'com.android.support:cardview-v7:23.0.1'
compile 'com.android.support:support-v4:23.0.1'
}

Errors:

FATAL EXCEPTION: main Process: it.moondroid.chatbot, PID: 20952 Theme: themes:{default=overlay:system, iconPack:system, fontPkg:system, com.android.systemui=overlay:system, com.android.systemui.navbar=overlay:system} java.lang.IllegalStateException: Could not execute method for android:onClick at android.view.View$DeclaredOnClickListener.onClick(View.java:4458) at android.view.View.performClick(View.java:5204) at android.view.View$PerformClick.run(View.java:21158) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5461) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Method.invoke(Native Method) at android.view.View$DeclaredOnClickListener.onClick(View.java:4453) at android.view.View.performClick(View.java:5204)  at android.view.View$PerformClick.run(View.java:21158)  at android.os.Handler.handleCallback(Handler.java:739)  at android.os.Handler.dispatchMessage(Handler.java:95)  at android.os.Looper.loop(Looper.java:148)  at android.app.ActivityThread.main(ActivityThread.java:5461)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)  Caused by: java.lang.ClassCastException: it.moondroid.chatbot.ChatBotApplication cannot be cast to it.moondroid.chatbot.SFBDemoApplication at it.moondroid.chatbot.SkypeActivity.onJoinMeetingButtonClick(SkypeActivity.java:143) at java.lang.reflect.Method.invoke(Native Method)  at android.view.View$DeclaredOnClickListener.onClick(View.java:4453)  at android.view.View.performClick(View.java:5204)  at android.view.View$PerformClick.run(View.java:21158)  at android.os.Handler.handleCallback(Handler.java:739)  at android.os.Handler.dispatchMessage(Handler.java:95)  at android.os.Looper.loop(Looper.java:148)  at android.app.ActivityThread.main(ActivityThread.java:5461)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

SkypeActivity.java

package it.moondroid.chatbot;

import android.app.AlertDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.TextView;

import com.microsoft.office.sfb.appsdk.AnonymousSession;
import com.microsoft.office.sfb.appsdk.Application;
import com.microsoft.office.sfb.appsdk.ConfigurationManager;
import com.microsoft.office.sfb.appsdk.Conversation;
import com.microsoft.office.sfb.appsdk.DevicesManager;
import com.microsoft.office.sfb.appsdk.Observable;
import com.microsoft.office.sfb.appsdk.SFBException;

import java.net.URI;

/**
 * Main Activity of the app.
 * The activity provides UI to join the meeting and navigate to the conversations view.
 */
public class SkypeActivity extends AppCompatActivity {

    Application application = null;
    ConfigurationManager configurationManager = null;
    DevicesManager devicesManager = null;
    ConversationPropertyChangeListener conversationPropertyChangeListener = null;
    Conversation anonymousConversation = null;
    AnonymousSession anonymousSession = null;
    TextView conversationStateTextView = null;
    Button joinMeetingButton = null;

    private Intent conversationsIntent = null;
boolean meetingJoined = false;

/**
 * Creating the activity initializes the SDK Application instance.
 * @param savedInstanceState saved instance.
 */
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_skype);

    this.application = Application.getInstance(this.getApplication().getApplicationContext());
    this.devicesManager = application.getDevicesManager();
    this.configurationManager = application.getConfigurationManager();

    // This flag will enable certain features that are in preview mode.
    // E.g. Audio / Video capability OnPrem topologies.
    this.configurationManager.enablePreviewFeatures(true);

    // Note that the sample enable video over cellular network. This is not the default.
    this.configurationManager.setRequireWiFiForVideo(false);

    // Max video channel count needs to be set to view video for more than one participant.
    this.configurationManager.setMaxVideoChannelCount(5);

    // Get UI elements.
    this.conversationStateTextView = (TextView)findViewById(R.id.statusTextViewId);
    this.joinMeetingButton = (Button)findViewById(R.id.joinMeetingButtonId);
    this.conversationsIntent = new Intent(this,ConversationsActivity.class);

    this.updateUiState();
}

@Override
protected void onDestroy() {
    this.configurationManager = null;
    this.application = null;

    super.onDestroy();
}

/**
 * Navigate to the conversations list view.
 * Note that, the conversations list view is provided only for demonstration purposes.
 * For anonymous meeting join it will always have a single conversation after meeting join is
 * successful.
 * @param view View
 */
public void onConversationsButtonClick(android.view.View view) {
    this.navigateToConversationsActivity();
}

/**
 * The click handler joins or leaves the meeting based on current state.
 *
 * @param view View.
 */
public void onJoinMeetingButtonClick(android.view.View view) {
    // Hide keyboard
    InputMethodHelper.hideSoftKeyBoard(this.getApplication().getApplicationContext(),
            view.getWindowToken());

    if (meetingJoined) {
        // Leave the meeting.
        try {
            this.anonymousConversation.leave();
            this.meetingJoined = false;
            this.updateUiState();

        } catch (SFBException e) {
            e.printStackTrace();
        }
    } else {
        //Join the meeting.
        // Get the display name.
        final android.widget.TextView displayNameTextView =
                (android.widget.TextView) findViewById(R.id.displayNameEditTextId);

        // Get the meeting uri
        final android.widget.EditText joinMeetingEditText =
                (android.widget.EditText) findViewById(R.id.meetingUriEditTextId);
        String meetingUriString = joinMeetingEditText.getText().toString();
        URI meetingUri = URI.create(meetingUriString);

        // Join meeting and monitor conversation state to determine meeting join completion.
        try {

            // Set the default device to Speaker
            //this.devicesManager.setActiveEndpoint(DevicesManager.Endpoint.LOUDSPEAKER);

            this.anonymousSession = this.application.joinMeetingAnonymously(
                    displayNameTextView.getText().toString(), meetingUri);

            this.anonymousConversation = this.anonymousSession.getConversation();
            SFBDemoApplication application = (SFBDemoApplication)getApplication();
            application.setAnonymousConversation(this.anonymousConversation);

            // Conversation begins in Idle state. It will move from Idle->Establishing->InLobby/Established
            // depending on meeting configuration.
            // We will monitor property change notifications for State property.
            // Once the conversation is Established, we will move to the next activity.
            this.conversationPropertyChangeListener = new ConversationPropertyChangeListener();
            this.anonymousConversation.addOnPropertyChangedCallback(this.conversationPropertyChangeListener);
        } catch (SFBException e) {
            e.printStackTrace();
        }
    }
}

/**
 * Update the UI state.
 */
public void updateUiState() {
    if (meetingJoined) {
        this.joinMeetingButton.setText(R.string.leave_meeting);
    } else {
        this.joinMeetingButton.setText(R.string.join_meeting);
        //conversationStateTextView.setText("");
    }
}

/**
 * Navigate to the Conversations activity.
 */
private void navigateToConversationsActivity() {
    startActivity(this.conversationsIntent);
}

/**
 * Determines meeting join state based on conversations state.
 */
public void updateConversationState() {
    Conversation.State state = this.anonymousConversation.getState();
    conversationStateTextView.setText(state.toString());
    switch (state) {
        case ESTABLISHED:
            this.meetingJoined = true;
            break;
        case IDLE:
            conversationStateTextView.setText("");
            this.meetingJoined = false;
            if (this.anonymousConversation != null) {
                this.anonymousConversation.removeOnPropertyChangedCallback(this.conversationPropertyChangeListener);
                this.anonymousConversation = null;
            }
            break;
        default:
    }

    // Refresh the UI
    this.updateUiState();

    if (meetingJoined) {
        this.navigateToConversationsActivity();
    }
}

/**
 * Helper method to show alerts.
 * @param message Alert message.
 */
private void showAlert(String message) {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage(message);
    builder.show();
}

/**
 * Callback implementation for listening for conversation property changes.
 */
class ConversationPropertyChangeListener extends Observable.OnPropertyChangedCallback {
    /**
     * onProperty changed will be called by the Observable instance on a property change.
     *
     * @param sender     Observable instance.
     * @param propertyId property that has changed.
     */
    @Override
    public void onPropertyChanged(Observable sender, int propertyId) {
        if (propertyId == Conversation.STATE_PROPERTY_ID) {
            updateConversationState();
        }
    }
}
}

SFBDemoApplication.java

package it.moondroid.chatbot;

import android.content.Context;
import android.support.multidex.MultiDex;
import android.support.multidex.MultiDexApplication;

import com.microsoft.office.sfb.appsdk.Conversation;

/**
 * Demo Application class
 */
public class SFBDemoApplication extends MultiDexApplication {

    @Override
    protected void attachBaseContext(Context base) {
         super.attachBaseContext(base);
         MultiDex.install(this);
    }

    /**
     * Saving the anonymous conversation to be shared across activities.
     */
    private Conversation anonymousConversation = null;

    /**
     * Save the anonymous conversation.
     * @param conversation
     */
    public void setAnonymousConversation(Conversation conversation) {
        this.anonymousConversation = conversation;
    }

    /**
     * Get the anonymous conversation.
     * @return Conversation conversation.
     */
    public Conversation getAnonymousConversation() {
        return this.anonymousConversation;
    }

}

Answer 1

I figured it out. I didn't update the AndroidManifest.xml

<application android:name='.SFBDemoApplication" >