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How to receive data from one activity to another - android

I'm trying to send an integer from one activity to another in Android studio. In my source class I have sent the data using putExtra() and in the recipient class, I am trying to receive it using getIntent(). However, I get the error 'Could not resolve method 'getIntent()' in the recipient class. Here is my code:
I'm a total newbie to Android studio as well as Java so if I'm missing something really obvious, please be considerate.
Source Activity:
public class AugmentedImageActivity extends AppCompatActivity {
private ArFragment arFragment;
private ImageView fitToScanView;
// Augmented image and its associated center pose anchor, keyed by the augmented image in
// the database.
private final Map<AugmentedImage, AugmentedImageNode> augmentedImageMap = new HashMap<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
arFragment = (ArFragment) getSupportFragmentManager().findFragmentById(R.id.ux_fragment);
fitToScanView = findViewById(R.id.image_view_fit_to_scan);
arFragment.getArSceneView().getScene().addOnUpdateListener(this::onUpdateFrame);
}
#Override
protected void onResume() {
super.onResume();
if (augmentedImageMap.isEmpty()) {
fitToScanView.setVisibility(View.VISIBLE);
}
}
/**
* Registered with the Sceneform Scene object, this method is called at the start of each frame.
*
* #param frameTime - time since last frame.
*/
private void onUpdateFrame(FrameTime frameTime) {
Frame frame = arFragment.getArSceneView().getArFrame();
// If there is no frame or ARCore is not tracking yet, just return.
if (frame == null || frame.getCamera().getTrackingState() != TrackingState.TRACKING) {
return;
}
Collection<AugmentedImage> updatedAugmentedImages =
frame.getUpdatedTrackables(AugmentedImage.class);
for (AugmentedImage augmentedImage : updatedAugmentedImages) {
switch (augmentedImage.getTrackingState()) {
case PAUSED:
// When an image is in PAUSED state, but the camera is not PAUSED, it has been detected,
// but not yet tracked.
int value=augmentedImage.getIndex();
Intent i = new Intent(AugmentedImageActivity.this, AugmentedImageNode.class);
i.putExtra("key",value);
startActivity(i);
String text = "Detected Image " + augmentedImage.getIndex();
SnackbarHelper.getInstance().showMessage(this, text);
break;
case TRACKING:
// Have to switch to UI Thread to update View.
fitToScanView.setVisibility(View.GONE);
// Create a new anchor for newly found images.
if (!augmentedImageMap.containsKey(augmentedImage)) {
AugmentedImageNode node = new AugmentedImageNode(this);
node.setImage(augmentedImage);
augmentedImageMap.put(augmentedImage, node);
arFragment.getArSceneView().getScene().addChild(node);
}
break;
case STOPPED:
augmentedImageMap.remove(augmentedImage);
break;
}
}
}
}
Recipient activity:
public class AugmentedImageNode extends AnchorNode {
private static final String TAG = "AugmentedImageNode";
// The augmented image represented by this node.
private AugmentedImage image;
private static CompletableFuture<ModelRenderable> ulCorner;
public AugmentedImageNode(Context context) {
Intent intent = getIntent();
Bundle extras = intent.getExtras();
int value = extras.getInt("key");
if (value == 0) {
// Upon construction, start loading the models for the corners of the frame.
if (ulCorner == null) {
ulCorner =
ModelRenderable.builder()
.setSource(context, Uri.parse("models/tinker.sfb"))
//.setSource(context, Uri.parse("models/borderfence-small2.sfb"))
.build();
}
}
}
#SuppressWarnings({"AndroidApiChecker", "FutureReturnValueIgnored"})
public void setImage(AugmentedImage image) {
this.image = image;
// If any of the models are not loaded, then recurse when all are loaded.
if (!ulCorner.isDone())// || !urCorner.isDone() || !llCorner.isDone() || !lrCorner.isDone())
{
CompletableFuture.allOf(ulCorner)//, urCorner, llCorner, lrCorner)
.thenAccept((Void aVoid) -> setImage(image))
.exceptionally(
throwable -> {
Log.e(TAG, "Exception loading", throwable);
return null;
});
}
// Set the anchor based on the center of the image.
setAnchor(image.createAnchor(image.getCenterPose()));
// Make the 4 corner nodes.
Vector3 localPosition = new Vector3();
Node cornerNode;
localPosition.set(-0.0f * image.getExtentX(), 0.1f, +0.5f * image.getExtentZ());
cornerNode = new Node();
cornerNode.setParent(this);
cornerNode.setLocalPosition(localPosition);
cornerNode.setLocalRotation(Quaternion.axisAngle(new Vector3(-1f, 0, 0), 90f));
cornerNode.setRenderable(ulCorner.getNow(null));
}
private void setLocalRotation() {
}
public AugmentedImage getImage() {
return image;
}
}

getIntent() method are only available in class which extends the activity[directly or indirectly]

Here is code how to use share preference in your scenario.I hope it will help you.
Instead of below code
Intent i = new Intent(AugmentedImageActivity.this, AugmentedImageNode.class);
i.putExtra("key",value);
startActivity(i);
Use this one
SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
Editor editor = pref.edit();
editor.putInt("Key", "int value");
editor.commit();
And retrieve preference value on your AugmentedImageNode screen using below code
SharedPreferences settings = getSharedPreferences("MyPref", MODE_PRIVATE);
int snowDensity = settings.getInt("Key", 0); //0 is the default value

remove the first three lines of your AugmentedImageNode(Context context) in recipient activity and replace it with following
int value = getIntent().getIntExtra("key",0);
where 0 is just default value.

getintent is working if you are extent Activity and AppCompatActivity
for example:
MainActivity.java
choice_a.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent=new Intent(MainActivity.this,SecondActivity.class);
//putExtra(key name,default value);
intent.putExtra("int_key",22);
startActivity(intent);
}
});
SecondActivity.java
public class SecondActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
//get intent values
Intent intent = getIntent();
Bundle extras = intent.getExtras();
int value = extras.getInt("int_key");
Log.e("Int_Value", "" + value);
// another way
int i = getIntent().getIntExtra("int_key", 0);
Log.e("Int_Value", "" + i);
}
}
In your code you have extend AnchorNode

How can I send an event from MainActivity.java to Javascript in React Native?

Currently the following code does successfully get the text that is being shared to the app, but I am having trouble finding out how to send this event to the Javascript side. I tried creating a new NavigationReactGateway but my app just crashes. I'm new to Java so I don't even know if I did it properly.
public class MainActivity extends SplashActivity {
/**
* Returns the name of the main component registered from JavaScript.
* This is used to schedule rendering of the component.
*/
protected String getMainComponentName() {
return "MyApplication";
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
String action = intent.getAction();
String type = intent.getType();
if (Intent.ACTION_SEND.equals(action) && type != null) {
if ("text/plain".equals(type)) {
handleSendText(intent);
}
}
}
void handleSendText(Intent intent) {
String sharedText = intent.getStringExtra(Intent.EXTRA_TEXT);
if (sharedText != null) {
// Send event to Javascript as "share" event
}
}
}
What is the correct way to send this event to Javascript?
The app has react-native-navigation and there are a lot of references to an event emitter, I'm just unsure how to get the react context to emit the event. If that makes any sense.

I was able to modify the handleSendText method to the following to send an event.
private void handleSendText(Intent intent) {
String sharedText = intent.getStringExtra(Intent.EXTRA_TEXT);
if (sharedText != null) {
ReactContext context = NavigationApplication.instance.getReactGateway().getReactContext();
if (context != null) {
WritableMap params = Arguments.createMap();
params.putString("event", sharedText);
context.getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
.emit("share", params);
}
}
}
I also had to change from using the onCreate method to using onStop, then the react context has been initialized and my event launches whether the app was already open or not.

You can use webView.addJavascriptInterface()
You can find documentation here.

Where to put in Android code to communicate with server over http

The question is how to communicate with an Android phone to a server, so that if the Activity is left and the call in the Activity was not successful to repeat the transaction once again automatically. Just now I use the AsyncTask of Android to communicate with the server:
new AsyncTask<String, Void, List<String>>() {
#Override
protected void onPreExecute(
showWaitDialog();
}
#Override
protected void onPostExecute(List<String> msgList) {
//here I put the handling after the POST ie. error and success handling
hideWaitDialog();
if (msgList.isEmpty() {
//success handling --> starting an new Activity
} else {
errorView.setText (...);
errorLayout.setVisibility (View.VISIBLE);
}
}
#Override
protected List<String> doInBackground(String... params) {
List<String> msgs = new ArrayList<String>();
try{
//for example submitting an JSONObject
JSONObject result = HttpUtils.sendHttpPost(
AppConstants.WEB_URL, jsonObject);
//error handling on the result
boolean hasErrors = JsonResult.isOk(result);
if (hasErrors) {
// adding errors to msgs list
String[] errorMessages = JsonResult.getErrorMessages (result,...);
fillList (msgs, errorMessages);
return msgs;
}
} catch (CommunicationError er) {
msgs.add (er...);
}
return msgs;
}
}
The problem with this approach is, that if I don't have a successful transmission of the data I must stay in the same Activity. Until now I show an error message to the user and he is in charge to submit by a button again the results to the server.
What I'm looking for is some Activity that remains persistent in the memory which runs later in the case that the transmission wasn't made.
As an application case I use this to dynamically upload pictures for a Waypoint in a map if I pressed that waypoint. In some case it can happens that the connection to the mobile service provider isn't available (mountains, forest, far apart from antenna). Then I want to leave the map Activity and switch to the detail view of this waypoint. In the success case I put the picture into my model classes and make an serialization. If the user clicks again on the same waypoint the picture is not loaded again. In the non success case I don't want to wait that the user clicks against on the waypoint to retrieve the image. In fact I need a background task, some sort of a queue that pictures of waypoints that are already visited on couldn't be retrieved are loaded until the communication part gives back a positive result and the image can be written into the model. The next time the user is pressing the Waypoint the picture will be then present.
Are there any best practices for making such a code implementation?
Is there any example around?
Is there a better way of doing this?

Yes, you need to Implement Intent Service for this requirement
According to the developers website
The IntentService class provides a straightforward structure for running an operation on a single background thread.
For complete details and working source code, Go through the Android Docs

Thanks to the answer of David.
I just read after the suggestion the tutorial at
[1] http://code.tutsplus.com/tutorials/android-fundamentals-intentservice-basics--mobile-6183
After my tests I prefered a Service (not an IntentService)
and created a service: SubmissionService
public class SubmissionIntentService extends Service {
private List<PendingMessage> pMsgList = new CopyOnWriteArrayList<PendingMessage>();
private Handler handler = new Handler();
private boolean hasAppStopped = false;
private Runnable runner;
public SubmissionIntentService() {
super();
Log.d (TAG, "Service created...");
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
PendingMessage pMessage = (PendingMessage) intent.getParcelableExtra(AppConstants.MESSAGE_OBJECT);
synchronized (pMsgList) {
pMsgList.add(pMessage);
}
if (runner == null) {
handler.postDelayed(runner = initializeRunnable(), 500);
}
return Service.START_NOT_STICKY;
}
private void runAsLongAppIsActive (Runnable runner) {
if (!hasAppStopped) {
handler.postDelayed (runner, SOME_INTERVAL_CONSTANT);
}
}
private Runnable initializeRunnable() {
Runnable result;
result = new Runnable() {
#Override
public void run() {
if (pMsgList.isEmpty()) {
runAsLongAppIsActive (this);
return;
}
PendingMessage[] pMArray = null;
synchronized(pMsgList) {
pMArray = pMsgList.toArray (new PendingMessage[pMsgList.size()]);
}
if (pMArray==null || pMArray.length==0) {
runAsLongAppIsActive (this);
return;
}
Log.d (TAG, "Message List size is actually :"+pMArray.length);
for (PendingMessage pM: pMArray) {
try {
JSONObject jsonMess = JSONSendMessage.buildOutput (pM);
JSONObject result = HttupUtils.sendHttpPost (WEB_URL, jsonMess);
boolean hasErrors = JSONResult.isOk (result);
if (hasErrors) {
//TODO: error handling in case of transmission
//don't remove the message from the queue
runAsLongAppIsActive(this);
return;
}
//remove pending transmission of the queue if success
synchronized (pMsgList) {
pMsgList.remove (pM);
}
//inform over receiver if activity is shown
Intent broadcastIntent = new Intent();
//put data in intent
sendBroadcast (intent);
//more important
WayPointModel model = ModelInstance.getWayPointModel();
model.addToModel (pM, result);
model.store();
} catch (Exception e) {
continue; //try to send other messages
}
}
runAsLongAppIsActive (this);
}
};
return result;
}
}
#Override
public void onDestroy() {
hasAppStopped = true;
handler.removeCallbacks (runner);
super.onDestroy();
}
}
Further I added a ResponseReceiver:
public class ResponseReceiver extends BroadcastReceiver {
public static final String ACTION_RESP = "MESSAGE_PROCESSED";
#Override
public void onReceive(Context context, Intent intent) {
//work in progress...
}
}
and in the Activity where I want to be informed about events:
public class SomeActivity extends Activity {
private ResponseReceiver receiver;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
IntentFilter filter = new IntentFilter(ResponseReceiver.ACTION_RESP);
filter.addCategory(Intent.CATEGORY_DEFAULT);
receiver = new ResponseReceiver();
registerReceiver(receiver, filter);
...
}
}
and finally to send messages over Http:
Intent msgIntent = new Intent(this, SubmissionIntentService.class);
msgIntent.putExtra(...);
startService(msgIntent);
don't forget to declare the service in your manifest:
<service android:name="ch.xxx.app.service.SubmissionIntentService" />
Observations:
- I called the method startService(...) from different Activities. The constructor is only called once.
==> I have just on instance of the service for all Activities (exactly what I need).
What I don't get until now:
- Putting back data to the Activity. What is if the Activity is at the moment no shown?

How to use a receiver info at other activity or fragment, in Android?

I'm trying to make a receiver that will notify if and when the phone is connected to the Internet.
Now, the thing is that I have got a main activity that handles two fragments.
In one of the fragments, I have a search method that needs to use the Internet.
So, what I am trying to do is: if there's no Internet, then the user will get a toast, after he/she pressed the search button.
In order to do this - I've written the following class in the main activity -
public class ConnectionChangeReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Boolean netBol;
ConnectivityManager connectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetInfo = connectivityManager
.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
boolean isConnected = activeNetInfo != null
&& activeNetInfo.isConnectedOrConnecting();
if (isConnected){
Boolean netBol = true;
}else{
netBol = false;
Toast.makeText(context, R.string.no_internet, Toast.LENGTH_LONG).show();
}
}
}
As you can see, I'm trying to use the Boolean netBol, to determine if there's a connection or not.
But the point is that i want to pass it to the search fragment, and I don't know how to do that.
I've also added the following line to the manifest:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
and I also put the following code in the main activity;
ConnectionChangeReceiver netReceiver = new ConnectionChangeReceiver();
IntentFilter filterNet = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
registerReceiver(netReceiver, filterNet);
For my understanding this is saying that I've declared on a receiver, but I need one at the fragment.
So what I'm asking is: what should I do in order to pass the info from the receiver to the fragment, so that I could know if there's internet or not?

Simple. Use otto
You will find the sample application here.
Change your code as follows:
You can do something like this in your receiver:
if (isConnected){
BusProvider.getInstance().post(new InternetAvailable(true));
}else{
BusProvider.getInstance().post(new InternetAvailable(false));
Toast.makeText(context, R.string.no_internet, Toast.LENGTH_LONG).show();
}
InternetAvailable class can be like this:
public class InternetAvailable {
private static boolean isInternetAvalable;
public InternetAvailable(boolean isInternetAvailableParam) {
isInternetAvailable = isInternetAvailableParam
}
#Produce public InternetAvailable isInternetAvailable() {
return isInternetAvailable;
}
}
The BusProvider class is like this:
public final class BusProvider {
private static final Bus BUS = new Bus();
public static Bus getInstance() {
return BUS;
}
private BusProvider() {
// No instances.
}
}
Modify your SearchFragment like this:
#Override public void onResume() {
super.onResume();
BusProvider.getInstance().register(this);
}
#Override public void onPause() {
super.onPause();
BusProvider.getInstance().unregister(this);
}

Shared preferences don't take effect until Preferences clicked

I'm writing an app for the Sony Smartwatch, using their SDK. Here's part of the main activity:
class SmartTickerActivity extends ControlExtension {
private Handler mHandler;
SmartTickerActivity(final String hostAppPackageName, final Context context, Handler handler) {
super(context, hostAppPackageName);
if (handler == null) {
throw new IllegalArgumentException("handler == null");
}
}
#Override
public void onStart() {
//do some stuff
PreferenceManager.setDefaultValues(mContext, R.xml.preference, false);
}
The problem is that the saved preferences aren't being applied on the Smartwatch when the application launches. Nor are the default preference values from XML. However, if I click on any of the app's preferences on the phone, the saved preference values are immediately applied to the Smartwatch.
Note that the main class has no onCreate() method, and that's throwing me for a loop.
Here's part of the Preference activity:
public class MyPreferenceActivity extends PreferenceActivity {
private OnSharedPreferenceChangeListener mListener = new OnSharedPreferenceChangeListener() {
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
Preference pref = findPreference(key);
if (pref instanceof ListPreference) {
ListPreference listPref = (ListPreference) pref;
pref.setSummary(listPref.getEntry().toString());
}
if (pref instanceof EditTextPreference) {
EditTextPreference editTextPref = (EditTextPreference) pref;
pref.setSummary(editTextPref.getText().toString());
}
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preference);
setSummaries();
setTypeface(SmartTickerActivity.mainLayout);
if (previewLayout != null) setTypeface(previewLayout);
// Handle read me
Preference readMe = findPreference(getText(R.string.preference_key_read_me));
readMe.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference readMe) {
showDialog(DIALOG_READ_ME);
return true;
}
});
// Handle about
Preference about = findPreference(getText(R.string.preference_key_about));
about.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference about) {
showDialog(DIALOG_ABOUT);
return true;
}
});
// Handle preview
Preference preview = findPreference(getText(R.string.preference_key_preview_dialog));
preview.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference preview) {
showDialog(DIALOG_PREVIEW);
return true;
}
});
}
I'm rather inexperienced at Android development, so the problem might very well have nothing to do whatsoever with the Sony SDK. Can anyone help?

You are correct, the preferences of the official sample extensions are not loaded until the PreferenceActivity is shown for the first time. If you use correct default values when accessing the preferences, this should not be a problem.
If you would like for the preferences to be loaded when the extension is initiated the first time, you could extend the android.app.Application class, and the onCreate method.
For example:
public class MySmartWatchApplication extends Application {
#Override
public void onCreate() {
super.onCreate();
PreferenceManager.setDefaultValues(this, R.xml.app_preferences, false);
}
}