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How to start and stop method with same button

How would one go about starting and stopping this camera (or preview?) with the same onClick button? Starting the camera was no issue, but now also closing the camera, with the same button is proving to be more difficult for a newbie like me.
When pressing the button a second time, the program crashes now, which is not ideal.
public class MainActivity extends AppCompatActivity {
PreviewView previewView;
public int REQUEST_CODE_PERMISSIONS = 101;
public final String[] REQUIRED_PERMISSIONS = new String[]{"android.permission.CAMERA"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
previewView = findViewById(R.id.previewView);
Button captureButton = findViewById(R.id.buttonPreview);
captureButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (allPermissionsGranted()) {
startCamera();
} else {
ActivityCompat.requestPermissions(MainActivity.this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS);
}
}
});
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull
int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (allPermissionsGranted()) {
startCamera();
} else {
Toast.makeText(this, "Permissions not granted by the user.", Toast.LENGTH_SHORT).show();
finish();
}
}
public boolean allPermissionsGranted() {
for (String permission : REQUIRED_PERMISSIONS) {
if (ContextCompat.checkSelfPermission(getApplicationContext(), permission) != PackageManager.PERMISSION_GRANTED) {
return false;
}
}
return true;
}
public void startCamera() {
ListenableFuture cameraProviderFuture = ProcessCameraProvider.getInstance(this);
cameraProviderFuture.addListener(() -> {
try {
ProcessCameraProvider cameraProvider = (ProcessCameraProvider) cameraProviderFuture.get();
Preview preview = new Preview.Builder().build();
CameraSelector cameraSelector = new CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build();
ImageAnalysis imageAnalysis =
new ImageAnalysis.Builder()
.setTargetResolution(new Size(1280, 720))
.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
.build();
preview.setSurfaceProvider(previewView.getSurfaceProvider());
Camera camera = cameraProvider.bindToLifecycle(
((LifecycleOwner) this),
cameraSelector,
preview,
imageAnalysis);
} catch (InterruptedException | ExecutionException e) {
}
}, ContextCompat.getMainExecutor(this));
}
}

Just need to create a boolean or int variable such as:
boolean ifCameraStarted=false;
When your called startCamera() you change this variable to true,and when you stopcamera change it to false;
When you click the button,you judge with this variable if it is true or false and do different things
booleam ifStarted=false;
captureButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(ifStarted==false){
startcamer();
}else{
stopcamer();
}
}
}

Cannot discover peers - Wifi Direct-

I want to have a connection between two android devices on the same local network and exchange data between them through my android app.
I used Wifi Direct Api with Broadcast receiver approach in order to get into that purpose, but for some reason the discoverPeers method does not get triggered.
This is the code for my MainActivity:
public class MainActivity extends AppCompatActivity {
private static MainActivity instance;
Button btnOnOff, btnDiscover, btnSend;
ListView listView;
TextView read_msg_box, connection_status;
EditText writeMessage;
WifiManager wifiManager;
WifiP2pManager mManager;
WifiP2pManager.Channel mChannel;
BroadcastReceiver mReceiver;
IntentFilter mIntentFilter;
List<WifiP2pDevice> peers = new ArrayList<WifiP2pDevice>();
String[] deviceNameArray;
WifiP2pDevice[] deviceArray;
WifiP2pManager.PeerListListener peerListListener = new WifiP2pManager.PeerListListener() {
#Override
public void onPeersAvailable(WifiP2pDeviceList peerList) {
if (!peerList.getDeviceList().equals(peers)) {
peers.clear();
peers.addAll(peerList.getDeviceList());
deviceNameArray = new String[peerList.getDeviceList().size()];
deviceArray = new WifiP2pDevice[peerList.getDeviceList().size()];
int index = 0;
for (WifiP2pDevice device : peerList.getDeviceList()) {
deviceNameArray[index] = device.deviceName;
deviceArray[index] = device;
index++;
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, deviceNameArray);
listView.setAdapter(adapter);
}
if (peers.size() == 0) {
Toast.makeText(getApplicationContext(), "No device Found", Toast.LENGTH_SHORT).show();
return;
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initialWork();
exqListener();
}
public static MainActivity getInstance() {
return instance;
}
private void exqListener() {
btnOnOff.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (wifiManager.isWifiEnabled() == true) {
wifiManager.setWifiEnabled(false);
btnOnOff.setText("Set To OFF ");
} else {
wifiManager.setWifiEnabled(true);
btnOnOff.setText("Set To ON");
}
}
});
btnDiscover.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() {
#Override
public void onSuccess() {
connection_status.setText("Discovery Started");
}
#Override
public void onFailure(int reason) {
connection_status.setText("Discovery Starting Failed");
}
});
}
});
}
private void initialWork() {
btnOnOff = (Button) findViewById(R.id.onOff);
btnDiscover = (Button) findViewById(R.id.discover);
btnSend = (Button) findViewById(R.id.sendButton);
read_msg_box = (TextView) findViewById(R.id.readMsg);
connection_status = (TextView) findViewById(R.id.connectionStatus);
writeMessage = (EditText) findViewById(R.id.writeMsg);
listView = (ListView) findViewById(R.id.peerListView);
wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
mChannel = mManager.initialize(this, getMainLooper(), null);
mReceiver = new WifiDirectBroadcastReceiver(mManager, mChannel, this);
mIntentFilter = new IntentFilter();
mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
}
#Override
protected void onResume() {
super.onResume();
registerReceiver(mReceiver, mIntentFilter);
}
#Override
protected void onPause() {
super.onPause();
unregisterReceiver(mReceiver);
}
}
And this is the one of the WifiDirectBroadcatReceiver:
public class WifiDirectBroadcastReceiver extends BroadcastReceiver {
private WifiP2pManager mManager;
private WifiP2pManager.Channel mChannel;
private AppCompatActivity mActivity;
public WifiDirectBroadcastReceiver(WifiP2pManager mManager, WifiP2pManager.Channel mChannel, AppCompatActivity mActivity) {
this.mManager = mManager;
this.mChannel = mChannel;
this.mActivity = mActivity;
}
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) {
int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, -1);
if (state == WifiP2pManager.WIFI_P2P_STATE_ENABLED) {
Toast.makeText(context, "Wifi is ON", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "Wifi is OFF", Toast.LENGTH_SHORT).show();
}
} else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) {
Toast.makeText(context, "Dkhal hnaya bro", Toast.LENGTH_SHORT).show();
if (mManager != null) {
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mManager.requestPeers(mChannel, MainActivity.getInstance().peerListListener);
}
} else if(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)) {
// Do something
} else if (WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)) {
// Do something
}
}
}
And this the permissions in AndroidManifest.xml:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
According to the code, there is a textView that should change its text once I press on the button btnDiscover, but when I do, nothing happens.
Knowing that I was turning my location service on before running the app, what would the error be ?
Every other approach to tackle the situation will be welcome.

Starting Android 11, certain permissions have to be requested during runtime, regardless of what's defined in your manifest. As the comments in your code point out, you should use requestPermissions to do so in your MainActivity and (optionally) react to the outcome using onRequestPermissionsResult.

Cannot run android app in background through service

I try to get current location when the app running in background, so I use service. However, the data does not change in background, the service does not work. I want to know the problem. Here is the code of the app.
MainActivity as follow:
public class MainActivity extends Activity {
Button btn_start;
private static final int REQUEST_PERMISSIONS = 100;
boolean boolean_permission;
TextView tv_latitude, tv_longitude, tv_address,tv_area,tv_locality;
SharedPreferences mPref;
SharedPreferences.Editor medit;
Double latitude,longitude;
Geocoder geocoder;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_start = (Button) findViewById(R.id.btn_start);
tv_address = (TextView) findViewById(R.id.tv_address);
tv_latitude = (TextView) findViewById(R.id.tv_latitude);
tv_longitude = (TextView) findViewById(R.id.tv_longitude);
tv_area = (TextView)findViewById(R.id.tv_area);
tv_locality = (TextView)findViewById(R.id.tv_locality);
geocoder = new Geocoder(this, Locale.getDefault());
mPref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
medit = mPref.edit();
btn_start.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (boolean_permission) {
if (mPref.getString("service", "").matches("")) {
medit.putString("service", "service").commit();
Intent intent = new Intent(getApplicationContext(), GoogleService.class);
startService(intent);
} else {
Toast.makeText(getApplicationContext(), "Service is already running", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(getApplicationContext(), "Please enable the gps", Toast.LENGTH_SHORT).show();
}
}
});
fn_permission();
}
private void fn_permission() {
if ((ContextCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)) {
if ((ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, android.Manifest.permission.ACCESS_FINE_LOCATION))) {
} else {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION
},
REQUEST_PERMISSIONS);
}
} else {
boolean_permission = true;
}
}
#Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode) {
case REQUEST_PERMISSIONS: {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
boolean_permission = true;
} else {
Toast.makeText(getApplicationContext(), "Please allow the permission", Toast.LENGTH_LONG).show();
}
}
}
}
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
latitude = Double.valueOf(intent.getStringExtra("latitude"));
longitude = Double.valueOf(intent.getStringExtra("longitude"));
List<Address> addresses = null;
try {
addresses = geocoder.getFromLocation(latitude, longitude, 1);
String cityName = addresses.get(0).getAddressLine(0);
String stateName = addresses.get(0).getAddressLine(1);
String countryName = addresses.get(0).getAddressLine(2);
tv_area.setText(addresses.get(0).getAdminArea());
tv_locality.setText(stateName);
tv_address.setText(countryName);
} catch (IOException e1) {
e1.printStackTrace();
}
tv_latitude.setText(latitude+"");
tv_longitude.setText(longitude+"");
tv_address.getText();
}
};
#Override
protected void onResume() {
super.onResume();
registerReceiver(broadcastReceiver, new IntentFilter(GoogleService.str_receiver));
}
#Override
protected void onPause() {
super.onPause();
unregisterReceiver(broadcastReceiver);
}
}
Service as follow:
public class GoogleService extends Service implements LocationListener{
boolean isGPSEnable = false;
boolean isNetworkEnable = false;
double latitude,longitude;
LocationManager locationManager;
Location location;
private Handler mHandler = new Handler();
private Timer mTimer = null;
long notify_interval = 1000;
public static String str_receiver =
"com.findmyelderly.findmyelderly.receiver";
Intent intent;
public GoogleService() {
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
mTimer = new Timer();
mTimer.schedule(new TimerTaskToGetLocation(),5,notify_interval);
intent = new Intent(str_receiver);
// fn_getlocation();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
private void fn_getlocation() {
locationManager = (LocationManager) getApplicationContext().getSystemService(LOCATION_SERVICE);
isGPSEnable = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
isNetworkEnable = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnable && !isNetworkEnable) {
} else {
if (isNetworkEnable) {
location = null;
try {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 0, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
Log.e("latitude", location.getLatitude() + "");
Log.e("longitude", location.getLongitude() + "");
latitude = location.getLatitude();
longitude = location.getLongitude();
fn_update(location);
}
}
} catch (SecurityException e) {
e.printStackTrace();
}
}
if (isGPSEnable) {
location = null;
try {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
Log.e("latitude", location.getLatitude() + "");
Log.e("longitude", location.getLongitude() + "");
latitude = location.getLatitude();
longitude = location.getLongitude();
fn_update(location);
}
}
} catch (SecurityException e) {
e.printStackTrace();
}
}
}
}
private class TimerTaskToGetLocation extends TimerTask {
#Override
public void run() {
mHandler.post(new Runnable() {
#Override
public void run() {
fn_getlocation();
}
});
}
}
private void fn_update(Location location){
intent.putExtra("latutide",location.getLatitude()+"");
intent.putExtra("longitude",location.getLongitude()+"");
sendBroadcast(intent);
}
}
build.gradle as follow
.........
compile 'com.android.support:appcompat-v7:25.0.0'
compile 'com.google.android.gms:play-services-location:10.0.1'
compile 'com.android.support:multidex:1.0.0'
AndroidManifest as follow
..........
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>
.........
<service android:name=".GoogleService" android:exported="false" android:enabled="true"/>
</application>
</manifest>
I am very puzzled.

One thing you could try is to check the permissions of the app on the phone itself. I've found with my device (Android version 6.0.1) it's not enough to just add "uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> and
"uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />"
in the manifest, you have to grant permissions to the app manually on the device.
To do this, go to Settings > Apps > 'yourApp' > Permissions and slide across the bar to turn on Location for that app.
I'm new enough to Android apps myself so there may be a bigger problem in your case I'm not sure but worth a try anyway!

I want to use setTheme to activity dialog without making black screen to the first Activity

I make an app to read barcode. I use surfaceview and camerasource on it. I want to show the result in activity dialog and when come back restart surfaceview and camera source so I add setTheme in the first line in onCreate Method like this
setTheme(android.R.style.Theme_DeviceDefault_Light_Dialog);
The problem is the first activity appears in black screen how to show first activity and I want to show the other parts of first activity under the dialog box
this is the whole on create method code for the first activity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
surfaceView = (SurfaceView) findViewById(R.id.cameraPreview);
txtShow = (TextView) findViewById(R.id.txtShow);
startBarcode();
}
public void startBarcode() {
barcodeDetector = new BarcodeDetector.Builder(this)
.setBarcodeFormats(Barcode.ALL_FORMATS)
.build();
cameraSource = new CameraSource.Builder(this, barcodeDetector)
.setRequestedPreviewSize(800, 600)
.setAutoFocusEnabled(true)
.build();
//Events
surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
#Override
public void surfaceCreated(SurfaceHolder holder) {
if (ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
//Make Request Runtime Permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA}, RequestCameraPermissionId);
return;
}
try {
cameraSource.start(surfaceView.getHolder());
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
//Make Request Runtime Permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA}, RequestCameraPermissionId);
return;
}
try {
cameraSource.start();
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
cameraSource.stop();
}
});
barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
#Override
public void release() {
}
#Override
public void receiveDetections(Detector.Detections<Barcode> detections) {
final SparseArray<Barcode> qrCodes = detections.getDetectedItems();
if (qrCodes.size() != 0) {
txtShow.post(new Runnable() {
#Override
public void run() {
//stop camera
cameraSource.stop();
//create vibrate
Vibrator vibrator = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
vibrator.vibrate(500);
//set result for Text View
txtShow.setText(qrCodes.valueAt(0).displayValue);
final String code = txtShow.getText().toString();
// surfaceView.setTop(200);
Intent intent = new Intent(MainActivity.this,InfoActivity.class);
//intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("code",code);
startActivity(intent);
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.barcode);
mp.start();

I want to restart camera source after it is stopped in the same Activity

I made an application for barcode detector so I used SurfaceView to handle camerasource. After camera detects barcode and returns its value I make it to stop. There is no function to restart the camera source and surface view on any event just one fuction which is camersource.start();
It starts but the problem it works in the background and I can't see anything how to fix this problem? and display surfaceview and camera source again.
here is the whole code of the activity onCreate Method
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
surfaceView = (SurfaceView) findViewById(R.id.cameraPreview);
txtShow = (TextView) findViewById(R.id.txtShow);
startBarcode();
}
public void startBarcode() {
barcodeDetector = new BarcodeDetector.Builder(this)
.setBarcodeFormats(Barcode.ALL_FORMATS)
.build();
cameraSource = new CameraSource.Builder(this, barcodeDetector)
.setRequestedPreviewSize(800, 600)
.setAutoFocusEnabled(true)
.build();
//Events
surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
#Override
public void surfaceCreated(SurfaceHolder holder) {
if (ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
//Make Request Runtime Permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA}, RequestCameraPermissionId);
return;
}
try {
cameraSource.start(surfaceView.getHolder());
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
//Make Request Runtime Permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.CAMERA}, RequestCameraPermissionId);
return;
}
try {
cameraSource.start();
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
cameraSource.stop();
}
});
barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
#Override
public void release() {
}
#Override
public void receiveDetections(Detector.Detections<Barcode> detections) {
final SparseArray<Barcode> qrCodes = detections.getDetectedItems();
if (qrCodes.size() != 0) {
txtShow.post(new Runnable() {
#Override
public void run() {
//create vibrate
Vibrator vibrator = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
vibrator.vibrate(500);
//set result for Text View
txtShow.setText(qrCodes.valueAt(0).displayValue);
// surfaceView.setTop(200);
cameraSource.stop();
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.barcode);
mp.start();

to restart after cameraSource.stop() you need:
cameraSource.start(surfaceView.getHolder());

After code captured you may stop camera source and restart OnCreate methode again. or you can call the activity again by using Intent like:
Intent intent= new Intent (getBaseContext,MainActivity.class); // your activity
startActivity(intent);