button fails to launch the new activity instead it goes back to launcher activity- android a

Issue

Hellow everyone ... I'm new to Android Application development .. Currently I'm working with BITalino Android API to develop my own Biosignal App. The issue I'm facing now when I press the start button ... which intended to move to the next Activity it take me back to the launcher Activity(Main Activity).No error or warning is given out .. its just not working the way it supposed to work

Below are the codes
Thank you very much in advance .....

manifest.xml

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@android:style/Theme.Holo.Light">
    <activity
        android:name=".ScanActivity"
        android:label="Anhalt BITadroid">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".DeviceActivity" />
    <activity android:name=".BiosignalDisplay"></activity>
</application>

Snippet of onClick() for Device_Activity(MainActivity)

public class DeviceActivity extends Activity implements OnBITalinoDataAvailable, View.OnClickListener {

private final String TAG = this.getClass().getSimpleName();

public final static String EXTRA_DEVICE = "info.plux.pluxapi.sampleapp.DeviceActivity.EXTRA_DEVICE";
public final static String FRAME = "info.plux.pluxapi.sampleapp.DeviceActivity.Frame";

private BluetoothDevice bluetoothDevice;

private BITalinoCommunication bitalino;
private boolean isBITalino2 = false;


private Handler handler;

private States currentState = States.DISCONNECTED;

private boolean isUpdateReceiverRegistered = false;

/*
 * UI elements
 */
private TextView nameTextView;
private TextView addressTextView;
private TextView elapsedTextView;
private TextView stateTextView;

private Button connectButton;
private Button disconnectButton;
private Button startButton;
private Button stopButton;

private LinearLayout bitalinoLinearLayout;
private Button stateButton;
private RadioButton digital1RadioButton;
private RadioButton digital2RadioButton;
private RadioButton digital3RadioButton;
private RadioButton digital4RadioButton;
private Button triggerButton;
private SeekBar batteryThresholdSeekBar;
private Button batteryThresholdButton;
private SeekBar pwmSeekBar;
private Button pwmButton;
private TextView resultsTextView;

private boolean isDigital1RadioButtonChecked = false;
private boolean isDigital2RadioButtonChecked = false;

private float alpha = 0.25f;

/*
 * Test with 2 device
 */
//    private BITalinoCommunication bitalino2;
//    private String identifierBITalino2 = "20:16:07:18:15:94";


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

    if(getIntent().hasExtra(EXTRA_DEVICE)){
        bluetoothDevice = getIntent().getParcelableExtra(EXTRA_DEVICE);
    }


    initView();
    setUIElements();

    handler = new Handler(getMainLooper()){
      @Override
      public void handleMessage(Message msg) {
          Bundle bundle = msg.getData();
          BITalinoFrame frame = bundle.getParcelable(FRAME);

          Log.d(TAG, frame.toString());

          if(frame != null){ //BITalino
              resultsTextView.setText(frame.toString());
          }
      }
    };
}

@Override
protected void onResume() {
    super.onResume();

    registerReceiver(updateReceiver, makeUpdateIntentFilter());
    isUpdateReceiverRegistered = true;
}

@Override
protected void onDestroy() {
    super.onDestroy();

    if(isUpdateReceiverRegistered) {
        unregisterReceiver(updateReceiver);
        isUpdateReceiverRegistered = false;
    }

    if(bitalino != null){
        bitalino.closeReceivers();
        try {
            bitalino.disconnect();
        } catch (BITalinoException e) {
            e.printStackTrace();
        }
    }

//        if(bitalino2 != null){
//            bitalino2.closeReceivers();
//            try {
//                bitalino2.disconnect();
//            } catch (BITalinoException e) {
//                e.printStackTrace();
//            }
//        }
    }



/*
 * UI elements
 */
private void initView(){
    nameTextView = (TextView) findViewById(R.id.device_name_text_view);
    addressTextView = (TextView) findViewById(R.id.mac_address_text_view);
    elapsedTextView = (TextView) findViewById(R.id.elapsed_time_Text_view);
    stateTextView = (TextView) findViewById(R.id.state_text_view);

    connectButton = (Button) findViewById(R.id.connect_button);
    disconnectButton = (Button) findViewById(R.id.disconnect_button);
    startButton = (Button) findViewById(R.id.start_button);
    stopButton = (Button) findViewById(R.id.stop_button);

    //bitalino ui elements
    bitalinoLinearLayout = (LinearLayout) findViewById(R.id.bitalino_linear_layout);
    stateButton = (Button) findViewById(R.id.state_button);
    digital1RadioButton = (RadioButton) findViewById(R.id.digital_1_radio_button);
    digital2RadioButton = (RadioButton) findViewById(R.id.digital_2_radio_button);
    digital3RadioButton = (RadioButton) findViewById(R.id.digital_3_radio_button);
    digital4RadioButton = (RadioButton) findViewById(R.id.digital_4_radio_button);
    triggerButton = (Button) findViewById(R.id.trigger_button);
    batteryThresholdSeekBar = (SeekBar) findViewById(R.id.battery_threshold_seek_bar);
    batteryThresholdButton = (Button) findViewById(R.id.battery_threshold_button);
    pwmSeekBar = (SeekBar) findViewById(R.id.pwm_seek_bar);
    pwmButton = (Button) findViewById(R.id.pwm_button);
    resultsTextView = (TextView) findViewById(R.id.results_text_view);
}

private void setUIElements(){
    if(bluetoothDevice.getName() == null){
        nameTextView.setText("BITalino");
    }
    else {
        nameTextView.setText(bluetoothDevice.getName());
    }
    addressTextView.setText(bluetoothDevice.getAddress());
    stateTextView.setText(currentState.name());

    Communication communication = Communication.getById(bluetoothDevice.getType());
    Log.d(TAG, "Communication: " + communication.name());
    if(communication.equals(Communication.DUAL)){
        communication = Communication.BLE;
    }

    bitalino = new        BITalinoCommunicationFactory().getCommunication(communication,this, this);
//        bitalino2 = new BITalinoCommunicationFactory().getCommunication(communication,this, this);

    connectButton.setOnClickListener(this);
    disconnectButton.setOnClickListener(this);
    startButton.setOnClickListener(this);
    stopButton.setOnClickListener(this);
    stateButton.setOnClickListener(this);
    digital1RadioButton.setOnClickListener(this);
    digital2RadioButton.setOnClickListener(this);
    digital3RadioButton.setOnClickListener(this);
    digital4RadioButton.setOnClickListener(this);
    triggerButton.setOnClickListener(this);
    batteryThresholdButton.setOnClickListener(this);
    pwmButton.setOnClickListener(this);
}

/*
 * Local Broadcast
 */
private final BroadcastReceiver updateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();
        if(ACTION_STATE_CHANGED.equals(action)){
            String identifier = intent.getStringExtra(IDENTIFIER);
            States state = States.getStates(intent.getIntExtra(EXTRA_STATE_CHANGED, 0));

            Log.i(TAG, identifier + " -> " + state.name());

            stateTextView.setText(state.name());

            switch (state){
                case NO_CONNECTION:
                    break;
                case LISTEN:
                    break;
                case CONNECTING:
                    break;
                case CONNECTED:
                    break;
                case ACQUISITION_TRYING:
                    break;
                case ACQUISITION_OK:
                    break;
                case ACQUISITION_STOPPING:
                    break;
                case DISCONNECTED:
                    break;
                case ENDED:
                    break;

            }
        }
        else if(ACTION_DATA_AVAILABLE.equals(action)){
            if(intent.hasExtra(EXTRA_DATA)){
                Parcelable parcelable = intent.getParcelableExtra(EXTRA_DATA);
                if(parcelable.getClass().equals(BITalinoFrame.class)){ //BITalino
                    BITalinoFrame frame = (BITalinoFrame) parcelable;
                    resultsTextView.setText(frame.toString());
                }
            }
        }
        else if(ACTION_COMMAND_REPLY.equals(action)){
            String identifier = intent.getStringExtra(IDENTIFIER);

            if(intent.hasExtra(EXTRA_COMMAND_REPLY) && (intent.getParcelableExtra(EXTRA_COMMAND_REPLY) != null)){
                Parcelable parcelable = intent.getParcelableExtra(EXTRA_COMMAND_REPLY);
                if(parcelable.getClass().equals(BITalinoState.class)){ //BITalino
                    Log.d(TAG, ((BITalinoState)parcelable).toString());
                    resultsTextView.setText(parcelable.toString());
                }
                else if(parcelable.getClass().equals(BITalinoDescription.class)){ //BITalino
                    isBITalino2 = ((BITalinoDescription)parcelable).isBITalino2();
                    resultsTextView.setText("isBITalino2: " + isBITalino2 + "; FwVersion: " + String.valueOf(((BITalinoDescription)parcelable).getFwVersion()));

//                        if(identifier.equals(identifierBITalino2) &&     bitalino2 != null){
//                            try {
//                                bitalino2.start(new int[]{0,1,2,3,4,5},     1);
//                            } catch (BITalinoException e) {
//                                e.printStackTrace();
//                            }
//                        }
                }
            }
        }
    }
};

private IntentFilter makeUpdateIntentFilter() {
    final IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(ACTION_STATE_CHANGED);
    intentFilter.addAction(ACTION_DATA_AVAILABLE);
    intentFilter.addAction(ACTION_EVENT_AVAILABLE);
    intentFilter.addAction(ACTION_DEVICE_READY);
    intentFilter.addAction(ACTION_COMMAND_REPLY);
    return intentFilter;
}

/*
 * Callbacks
 */

@Override
public void onBITalinoDataAvailable(BITalinoFrame bitalinoFrame) {
    Message message = handler.obtainMessage();
    Bundle bundle = new Bundle();
    bundle.putParcelable(FRAME, bitalinoFrame);
    message.setData(bundle);
    handler.sendMessage(message);
}


@Override
public void onClick(View view) {
    switch (view.getId()){
        case R.id.connect_button:
            try {
                bitalino.connect(bluetoothDevice.getAddress());
            } catch (BITalinoException e) {
                e.printStackTrace();
            }

            break;
        case R.id.disconnect_button:
            try {
                bitalino.disconnect();
            } catch (BITalinoException e) {
                e.printStackTrace();
            }

           break;

        case R.id.start_button:{
            Intent Recordingintent = new Intent(getApplicationContext(), BiosignalDisplay.class);
            startActivity(Recordingintent);}
            break;

        case R.id.stop_button:
            Intent exit = new Intent(this, ScanActivity.class);
            startActivity(exit);
            break;
    }
}
}

main.xmlenter code here

Solution

This questions really can't be answered with what information was provided, so I'll instead give some general guidance on how to find these types of problems and the actual solution as per the context provided in the comments.

---

If your app closes when you don't expect it, the usual cause of this is an uncaught RuntimeException. These, in contrast to "checked exceptions", don't have to be surrounded by a try-catch for the compiler to be happy. If they are not caught, they will terminate the program/App.

The first step to fixing these exceptions is to check the Android Log (Log Cat) for the exception and a stack-trace. In Android Studio, the Log output is available at the bottom left corner.

If the Log is very busy with a lot of stuff going on, you can filter it by type and application. For the purpose of finding out error, we filter by our App and the "Error" log-level.

---

The actual exception from the question (from the comments) is:

java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

This (very likely) means that the BiosignalDisplay-activity extends AppCompactActivity from the Android Support Library, but the entry in the AndroidManifest.xml doesn't set a support-library theme for the activity.

This can be fixed by setting the theme-attribute on either the specific <activity>-tag or on the <application>-tag to any theme under Theme.AppCompat, for example Theme.AppCompat.Light.NoActionBar.

For more information on this, see: You need to use a Theme.AppCompat theme (or descendant) with this activity

Answered By - Lukas Knuth