finish() method in android closing the entire application

Question

In my MainScreen.java class I am calling startActivityForResult() method when I am clicking on a image:

case R.id.add_device_btn:
case R.id.add_device_btn_text:
    startActivityForResult(new Intent(MainScreen.this, DeviceDiscovery.class), REQUEST_DISCOVERY);
    break;

In my DeviceDiscovery class I wrote this code when I am clicking on the list Item

@Override
protected void onListItemClick(ListView lv, View view, int position, long id) {
    super.onListItemClick(lv, view, position, id);
    // since user selected already a device we do not need to scan for more devices
    localDevice.stopScan();

    final String address = ((RemoteDevice)adapter.getItem(position)).getAddress();
    Intent i = new Intent();
    i.putExtra(ADDRESS_EXTRA, address);
    setResult(RESULT_OK, i);
    finish();
}

I did this because when I click on the list it should come to the onActivityResult() method.

But now when I click on the list item the entire application get closed, the control is not going to that onActivityResult() method.

So how to fix this problem?

onActivityResult() method

      @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    switch(requestCode){
    case REQUEST_DISCOVERY:
        if (resultCode == RESULT_OK){
            String address = data.getStringExtra(DeviceDiscovery.ADDRESS_EXTRA);
            // add only if device is not already in the list
            if (!devices.deviceEntries.contains(new BTDevice(address))){
                db.open();
                db.createDevice(new BTDevice(LocalDevice.getInstance().getRemoteForAddr(address)));
                devices.deviceEntries = db.fetchAllDevices();
                db.close();
                devices.notifyDataSetChanged();
            }
            else {
                Logger.d(TAG, "Duplicate entry: device already added");
                Toast.makeText(this, "Selected device is already in your list", Toast.LENGTH_SHORT).show();
            }
        }
        break;
    }
}

this is my MainScreen class

    public class MainScreen extends ListActivity implements OnClickListener{



public static final int REQUEST_DISCOVERY = 2;

private static final int MENU_ITEM_SHOW_EVENTS = 1;
private static final int MENU_ITEM_CONNECT = 2;
private static final int MENU_ITEM_REMOVE_DEVICE = 3;
private static final int MENU_ITEM_MOVE_UP = 4;
private static final int MENU_ITEM_MOVE_DOWN = 5;

private static final int MENU_ABOUT = 10;

private static final int DIALOG_ABOUT = 1;




AmarinoDbAdapter db;
DeviceListAdapter devices;

boolean isBound = false;
MyHandler handler = new MyHandler();


BroadcastReceiver receiver = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {

        String action = intent.getAction();
        if (action == null) return;
        Logger.d(TAG, action + " received");

        if (AmarinoIntent.ACTION_CONNECTED_DEVICES.equals(action)){
            updateDeviceStates(intent.getStringArrayExtra(AmarinoIntent.EXTRA_CONNECTED_DEVICE_ADDRESSES));
            return;
        }

        final String address = intent.getStringExtra(AmarinoIntent.EXTRA_DEVICE_ADDRESS);
        if (address == null) return;

        Message msg = new Message();

        if (AmarinoIntent.ACTION_CONNECTED.equals(action)){
            msg.what = MyHandler.CONNECTED;
        }
        else if (AmarinoIntent.ACTION_DISCONNECTED.equals(action)){
            msg.what = MyHandler.DISCONNECTED;
        }
        else if (AmarinoIntent.ACTION_CONNECTION_FAILED.equals(action)){
            msg.what = MyHandler.CONNECTION_FAILED;
        }
        else if (AmarinoIntent.ACTION_PAIRING_REQUESTED.equals(action)){
            msg.what = MyHandler.PAIRING_REQUESTED;
        }
        else return;

        msg.obj = address;
        handler.sendMessage(msg);
    }
};  

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Logger.d(TAG, "onCreate");
    setContentView(R.layout.main);

    findViewById(R.id.add_device_btn).setOnClickListener(this);
    findViewById(R.id.add_device_btn_text).setOnClickListener(this);

    findViewById(R.id.monitoring_btn).setOnClickListener(this);
    findViewById(R.id.monitoring_btn_text).setOnClickListener(this);

    findViewById(R.id.settings_btn).setOnClickListener(this);
    findViewById(R.id.settings_btn_text).setOnClickListener(this);

    /* Since the settings button is not used so far, I hide it */
    findViewById(R.id.settings_btn_layout).setVisibility(View.GONE);


    db = new AmarinoDbAdapter(this);
    db.open();
    devices = new DeviceListAdapter(this, db.fetchAllDevices());
    db.close();

    setListAdapter(devices);
    registerForContextMenu(getListView());

    showReleaseNotes();
}


private void showReleaseNotes() {
    SharedPreferences prefs = getPreferences(MODE_PRIVATE);
    int versionCode = getVersionCode();
    if (prefs.getInt(PREF_VERSION, 0) != versionCode){
        showDialog(DIALOG_ABOUT);
        prefs.edit().putInt(PREF_VERSION, versionCode).commit();
    }
}


@Override
protected void onStart() {
    super.onStart();
}

@Override
protected void onResume() {
    super.onResume();
    // listen for device state changes
    IntentFilter intentFilter = new IntentFilter(AmarinoIntent.ACTION_CONNECTED_DEVICES);
    //intentFilter.addAction(AmarinoIntent.ACTION_CONNECTED);
    //intentFilter.addAction(AmarinoIntent.ACTION_DISCONNECTED);
    intentFilter.addAction(AmarinoIntent.ACTION_CONNECTION_FAILED);
    intentFilter.addAction(AmarinoIntent.ACTION_PAIRING_REQUESTED);
    registerReceiver(receiver, intentFilter);

    // request state of devices
    Intent intent = new Intent(this, AmarinoService.class);
    intent.setAction(AmarinoIntent.ACTION_GET_CONNECTED_DEVICES);
    startService(intent);
}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(receiver);
}

@Override
protected void onStop() {
    super.onStop();
}

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




private void updateDeviceStates(String[] connectedDevices){
    if (connectedDevices == null) {
        Logger.d(TAG, "no connected devices");
        for (BTDevice device : devices.deviceEntries){
            Message msg = new Message();
            msg.what = MyHandler.DISCONNECTED;
            msg.obj = device.address;
            handler.sendMessage(msg);
        }
        return;
    }

    Logger.d(TAG, "connected devices detected: " + connectedDevices.length);
    for (BTDevice device : devices.deviceEntries){
        boolean connected = false;
        Message msg = new Message();
        // this is normally a very short list, not matter that this is in O(n^2)
        for (int i=0; i<connectedDevices.length; i++){
            if (connectedDevices[i].equals(device.address)){
                msg.what = MyHandler.CONNECTED;
                connected = true;
                break;
            }
        }
        if (!connected){
            msg.what = MyHandler.DISCONNECTED;
        }
        msg.obj = device.address;
        handler.sendMessage(msg);
    }
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    menu.add(Menu.NONE, MENU_ABOUT, Menu.FIRST, R.string.menu_about)
        .setIcon(R.drawable.about_icon);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
    case MENU_ABOUT:
        showDialog(DIALOG_ABOUT);
    }
    return super.onOptionsItemSelected(item);

}

@Override
protected Dialog onCreateDialog(int id) {
    Dialog dialog;
    switch(id) {
        case DIALOG_ABOUT:
            dialog = getAboutBox();
            break;

        default:
            dialog = null;
    }
    return dialog;
}

private AlertDialog getAboutBox() {
    String title = getString(R.string.app_name) + " build " + getVersion(this);

    return new AlertDialog.Builder(MainScreen.this)
        .setTitle(title)
        .setView(View.inflate(this, R.layout.about, null))
        .setIcon(R.drawable.icon_small)
        .setPositiveButton("OK", null)
        .create();

}


@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    // Setup the menu header
    AdapterView.AdapterContextMenuInfo info;
    info = (AdapterView.AdapterContextMenuInfo) menuInfo;
    BTDevice device = devices.deviceEntries.get(info.position);
    menu.setHeaderTitle(device.name);

    menu.add(0, MENU_ITEM_CONNECT, 0, 
            device.state == AmarinoIntent.DISCONNECTED ? R.string.connect : R.string.disconnect);
    menu.add(0, MENU_ITEM_SHOW_EVENTS, 0, R.string.show_events);
    menu.add(0, MENU_ITEM_REMOVE_DEVICE, 0, R.string.remove_device);

    //menu.add(0, MENU_ITEM_MOVE_UP, 0, "Move up");
    //menu.add(0, MENU_ITEM_MOVE_DOWN, 0, "Move down");

}

@Override
public boolean onContextItemSelected(MenuItem item) {
    AdapterView.AdapterContextMenuInfo info;
    info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    BTDevice device = devices.deviceEntries.get(info.position);

    switch (item.getItemId()) {
    case MENU_ITEM_REMOVE_DEVICE:
        // before we remove the device, we disconnect it if connected
        if (device.state == AmarinoIntent.CONNECTED){
            Toast.makeText(this, "Please disconnect the device before removing it!", Toast.LENGTH_SHORT).show();
        }
        else {
            db.open();
            db.deleteDevice(device.id);
            devices.deviceEntries = db.fetchAllDevices();
            db.close();
            devices.notifyDataSetChanged();
        }

        return true;
    case MENU_ITEM_SHOW_EVENTS:
        onEventListBtnClick(info.position);
        return true;
    case MENU_ITEM_CONNECT:
        Button btn = (Button) info.targetView.findViewById(R.id.connect_btn);
        onConnectBtnClick(btn, info.position);
        return true;
    case MENU_ITEM_MOVE_UP: 
        // TODO move this selected device one position up
        return true;
    case MENU_ITEM_MOVE_DOWN: 
        // TODO move this selected device one position down
        return true;
    }
    return false;
}


@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    openContextMenu(v);
}


@Override
public void onClick(View v) {
    switch(v.getId()){
        case R.id.connect_btn:
            Button btn = (Button)v;
            int postion = (Integer) v.getTag();
            onConnectBtnClick(btn, postion);
            break;

        case R.id.list_btn:
            int pos = (Integer) v.getTag();
            onEventListBtnClick(pos);
            break;

        case R.id.add_device_btn:
        case R.id.add_device_btn_text:
            Intent obj=new Intent(MainScreen.this,DeviceDiscovery.class);
            //getParent().
            startActivityForResult(obj,1001);
            break;

        case R.id.monitoring_btn:
        case R.id.monitoring_btn_text:
            startActivity(new Intent(MainScreen.this, Monitoring.class));
            break;

        case R.id.settings_btn:
        case R.id.settings_btn_text:
            // TODO Perhaps we need a settings button in the future
            Toast.makeText(this, "not implemented yet", Toast.LENGTH_SHORT).show();
            break;
    }
}


private void onConnectBtnClick(Button btn, int postion) {
    Intent i = new Intent(MainScreen.this, AmarinoService.class);
    i.putExtra(AmarinoIntent.EXTRA_DEVICE_ADDRESS, devices.deviceEntries.get(postion).address);

    if ( btn.getText().equals(getString(R.string.connect)) )
        i.setAction(AmarinoIntent.ACTION_CONNECT);
    else
        i.setAction(AmarinoIntent.ACTION_DISCONNECT);

    btn.setEnabled(false);
    btn.setText(R.string.connecting);

    startService(i);
} 

private void onEventListBtnClick(int pos){
    Intent intent = new Intent(MainScreen.this, EventListActivity.class);
    intent.putExtra(AmarinoIntent.EXTRA_DEVICE, devices.deviceEntries.get(pos));
    startActivity(intent);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    Toast.makeText(getApplicationContext(), "In mAIn", Toast.LENGTH_SHORT).show();
    //super.onActivityResult(requestCode, resultCode, data);
    switch(requestCode){
    case 1001:
        if (resultCode == RESULT_OK){
            String address = data.getStringExtra(DeviceDiscovery.ADDRESS_EXTRA);
            // add only if device is not already in the list
            if (!devices.deviceEntries.contains(new BTDevice(address))){
                db.open();
                db.createDevice(new BTDevice(LocalDevice.getInstance().getRemoteForAddr(address)));
                devices.deviceEntries = db.fetchAllDevices();
                db.close();
                devices.notifyDataSetChanged();
            }
            else {
                Logger.d(TAG, "Duplicate entry: device already added");
                Toast.makeText(this, "Selected device is already in your list", Toast.LENGTH_SHORT).show();
            }
        }
        break;
    }
}

private class MyHandler extends Handler {

    protected static final int CONNECTED = 1;
    protected static final int DISCONNECTED = 2;
    protected static final int CONNECTION_FAILED = 3;
    protected static final int PAIRING_REQUESTED = 4;

    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        final int what = msg.what;
        final String address = (String)msg.obj;

        for (int i=0; i<devices.getCount();i++){
            BTDevice device = (BTDevice)devices.getItem(i);

            if (address.equals(device.address)){
                View view = getListView().getChildAt(i);
                Button btn = (Button)view.findViewById(R.id.connect_btn);
                btn.setEnabled(true);

                switch (what) {
                    case CONNECTED:
                        setDeviceConnected(device, view, btn);
                        break;
                    case CONNECTION_FAILED:
                        Toast.makeText(MainScreen.this, "Connection failed!", Toast.LENGTH_SHORT).show();
                    case DISCONNECTED:
                        setDeviceDisconnected(device, view, btn);
                        break;
                    case PAIRING_REQUESTED:
                        Toast.makeText(MainScreen.this, 
                                "Device is not paired!\n\nPlease pull-down the notification bar to pair your device.\n\n", Toast.LENGTH_LONG).show();
                        setDeviceDisconnected(device, view, btn);
                        break;
                }
                view.invalidate();
            }
        } // end for

    } // end handleMessage()

    private void setDeviceConnected(BTDevice device, View view, Button btn) {
        device.state = AmarinoIntent.CONNECTED;
        view.findViewById(R.id.connected).setBackgroundResource(R.color.connected_on);
        view.findViewById(R.id.disconnected).setBackgroundResource(R.color.disconnected_off);
        btn.setText(R.string.disconnect);
    }

    private void setDeviceDisconnected(BTDevice device, View view, Button btn) {
        device.state = AmarinoIntent.DISCONNECTED;
        view.findViewById(R.id.connected).setBackgroundResource(R.color.connected_off);
        view.findViewById(R.id.disconnected).setBackgroundResource(R.color.disconnected_on);
        btn.setText(R.string.connect);
    }


}

public static String getVersion(Context context) {
    String version = "1.0"; 
    try { 
        PackageInfo pi = context.getPackageManager().getPackageInfo(context.getPackageName(), 0); 
        version = pi.versionName; 
    } catch (PackageManager.NameNotFoundException e) { 
        Log.e(TAG, "Package name not found", e); 
    } 
    return version;
}

private int getVersionCode() {
    int code = 1; 
    try { 
        PackageInfo pi = getPackageManager().getPackageInfo(getPackageName(), 0); 
        code = pi.versionCode; 
    } catch (PackageManager.NameNotFoundException e) { 
        Log.e(TAG, "Package name not found", e); 
    } 
    return code;
}


private class DeviceListAdapter extends BaseAdapter {

    ArrayList<BTDevice> deviceEntries;
    Context context;

    @SuppressWarnings("unused")
    public DeviceListAdapter(Context context){
        this.context = context;
    }

    public DeviceListAdapter(Context context, ArrayList<BTDevice> deviceEntries){
        this.context = context;
        this.deviceEntries = deviceEntries;
    }

    public int getCount() {
        if (deviceEntries != null) {
            return deviceEntries.size();
        }
        return 0;
    }

    public Object getItem(int position) {
        return deviceEntries.get(position);
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        LinearLayout view = null;
        BTDevice device = deviceEntries.get(position);

        if (convertView == null) {
            view = new LinearLayout(context);
            LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            vi.inflate(R.layout.devices_list_item, view, true);
        } else {
            view = (LinearLayout) convertView;
        }

        TextView name = (TextView) view.findViewById(R.id.device_name);
        TextView address = (TextView) view.findViewById(R.id.device_address);
        Button eventListBtn = (Button) view.findViewById(R.id.list_btn);
        Button connectBtn = (Button) view.findViewById(R.id.connect_btn);

        // lets remember which address is associated with our buttons
        connectBtn.setTag(position);
        eventListBtn.setTag(position);

        connectBtn.setOnClickListener(MainScreen.this);
        eventListBtn.setOnClickListener(MainScreen.this);

        name.setText((name==null) ? "NONAME" : device.name);
        address.setText(device.address);

        return view;
    }

}

}

This my DeviceDiscovery class

     public class DeviceDiscovery extends ListActivity {

protected static String ADDRESS_EXTRA = "device_address";
public static final int REQUEST_DISCOVERY = 2;

@SuppressWarnings("unused")
private static final String TAG = "DeviceDiscovery";

private DeviceAdapter adapter;
private LocalDevice localDevice;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setTitle("Discovered Devices");
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setContentView(R.layout.discovered_devices_list);

    adapter = new DeviceAdapter();
    setListAdapter(adapter);

    setProgressBarIndeterminateVisibility(true);
    localDevice = LocalDevice.getInstance();
}

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

    localDevice.init(this, new ReadyListener(){

        @Override
        public void ready() {
            localDevice.scan(new ScanListener(){

                @Override
                public void deviceFound(RemoteDevice device) {

                    synchronized(adapter.discoveredDevices){
                        Vector<RemoteDevice> addedDevices = adapter.discoveredDevices;
                        for (RemoteDevice rd : addedDevices){
                            if (rd.getAddress().equals(device.getAddress())){
                                Log.d(TAG, "device already in list -> renew");
                                adapter.discoveredDevices.remove(rd);
                            }
                        }
                        adapter.discoveredDevices.add(device);
                    }
                    adapter.notifyDataSetChanged();
                }

                @Override
                public void scanCompleted() {
                    setProgressBarIndeterminateVisibility(false);
                }
            });
        } // end ready()
    });

}


@Override
protected void onStop() {
    super.onStop();
    // TODO change source of AndroidBluetoothLibrary to fix the bug
    // this might run in an exception, because of a race condition
    // see issue 22 at http://code.google.com/p/android-bluetooth/issues/detail?id=22
    localDevice.destroy();
}


@Override
protected void onListItemClick(ListView lv, View view, int position, long id) {
    super.onListItemClick(lv, view, position, id);
    // since user selected already a device we do not need to scan for more devices
    localDevice.stopScan();

    final String address = ((RemoteDevice)adapter.getItem(position)).getAddress();
    Intent i = new Intent();
    i.putExtra(ADDRESS_EXTRA, address);
    setResult(RESULT_OK, i);
    finish();
}

@Override
protected void onDestroy() {

    // TODO Auto-generated method stub

}


private class DeviceAdapter extends BaseAdapter {

    Vector<RemoteDevice> discoveredDevices = new Vector<RemoteDevice>();

    public int getCount() {
        if (discoveredDevices != null) {
            return discoveredDevices.size();
        }
        return 0;
    }

    public Object getItem(int position) {
        return discoveredDevices.get(position);
    }

    public long getItemId(int position) {
        return 0;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        LinearLayout view = null;

        if (convertView == null) {
            view = new LinearLayout(DeviceDiscovery.this);
            String inflater = Context.LAYOUT_INFLATER_SERVICE;
            LayoutInflater vi = (LayoutInflater) DeviceDiscovery.this.getSystemService(inflater);
            vi.inflate(R.layout.discovered_devices_list_item, view, true);
        } else {
            view = (LinearLayout) convertView;
        }

        TextView addressTextView = (TextView) view.findViewById(R.id.device_address);
        TextView nameTextView = (TextView) view.findViewById(R.id.device_name);

        RemoteDevice device = discoveredDevices.get(position);
        String address = device.getAddress();
        String name = device.getFriendlyName();

        addressTextView.setText(address);
        nameTextView.setText((name==null) ? "NONAME" : name);

        return view;
    }
}

}

Still I can't find the solution , Its still closing the entire application and its not going to that onActivityResult() method also

Answer 1

I got the answer, Its like I forgot to remove the

    android:noHistory="true"

from the manifest.xml file, now I removed this and its working fine now.

Thanks to all for your reply.