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How do I create a new object on every button click?

I am creating a notes app, and I've all but finished it. My app starts on the main activity, which shows a recylcerView displaying all of the saved notes. To create a new note, you press a button, which sends you to another activity where you write your note. You then press a button that saves the note as an instance of the Note class and sends that object instance back to the main activity where it updates the recyclerView.
My problem is, every time I press the save button for my note, it just updates the Note instance instead of creating an entirely new one. How do I get it to create a new instance of the Note class so that I can have more than one saved note?
Here is my code for the save button:
Intent intent = new Intent(AddNoteActivity.this, MainActivity.class);
String mTitle = title.getText().toString();
String mContent = content.getText().toString();
intent.putExtra("notePar", new Note(mTitle, mContent));
startActivity(intent);
Here is my code for the mainactivity:
Intent intent = getIntent();
Note sentParcNote = intent.getParcelableExtra("notePar");
if(sentParcNote != null) {
notes.add(sentParcNote);
}

You are using startActivity(intent) to navigate from AddNoteActivity to MainActivity, this method is used to start a new activity, which means, the system will create a new instance of MainActivity class and put it at the top of the activity stack. This way you will always have 0 or 1 note (when sentParcNote != null)
I would suggest to use startActivityForResult when you navigate from MainActivity to AddNoteActivity and call setResult in your AddNoteActivity
Example:
MainActivity:
Declare this static int at the top of your class (e.g: just before onCreate method)
private static final int ADD_NOTE_ACTIVITY_REQUEST_CODE = 2;
Then add this piece of code on your button action to start AddNoteActivity:
Intent addNoteIntent = new Intent(this, AddNoteActivity.class);
startActivityForResult(addNoteIntent, ADD_NOTE_ACTIVITY_REQUEST_CODE);
Then to catch the new note from AddNoteActivity
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == ADD_NOTE_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
Note sentParcNote = data.getParcelableExtra("notePar");
if(sentParcNote != null) {
notes.add(sentParcNote);
}
}
}
}
AddNoteActivity:
add this piece of code to your save button action
String mTitle = title.getText().toString();
String mContent = content.getText().toString();
Intent intent = new Intent();
intent.putExtra("notePar", new Note(mTitle, mContent));
setResult(RESULT_OK, intent);
// finish closes the current activity which means in this case it goes back to the MainActivity
finish();
I would suggest using local storage to save your notes otherwise if you restart the app you will always have 0 notes.

Android: pass data from initial activity (launching Zxing scanner) to onActivityResult callback

I use the library zxing-android-embedded in my Android App. Before calling initiateScan() method to start the scanner from my activity, I set a class variable scanedItemId to know on which item I clicked to scan:
[...]
scanedItemId = currentItem.id // The current item where we clicked on.
IntentIntegrator qrCodeScanner = new IntentIntegrator(MyActivity.this);
qrCodeScanner.setOrientationLocked(false);
qrCodeScanner.initiateScan();
[...]
Then I get the result via onActivityResult method. It works well but my class variable scanedItemId is null because the activity is relaunched. Is it possible to keep my initial instance of MyActivity (with the scanedItemId well set) or to pass the value I need thru the IntentIntegrator to get it back on the new instance of MyActivity?
[...]
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case IntentIntegrator.REQUEST_CODE:
// Here the scanedItemId is always null.
[...]
If possible I wouldn't like to use a hard persistence (like db or file) to get my scanedItemId value.
Hope it's clear enough

You can add more custom data like this :
scanedItemId = currentItem.id // The current item where we clicked on.
IntentIntegrator qrCodeScanner = new IntentIntegrator(MyActivity.this);
quCodeScanner.addExtra("ITEM_ID", scanedItemId);//add your data
qrCodeScanner.setOrientationLocked(false);
qrCodeScanner.initiateScan();
Because library which you used didn't return your data. You can fork that library and add some code like below:
In CaptureManager class
edit initializeFromIntent method
if (intent != null) {
data = intent.getIntExtra("ITEM_ID", 0);//save your data
}
and resultIntent method
intent.putExtra("ITEM_ID", data);//return your data
Now in onActivityResult you can get your data
IntentResult result = IntentIntegrator.parseActivityResult(resultCode, data);
if (result.getOriginalIntent().hasExtra("ITEM_ID")) {
Toast.makeText(this,"Item Id : " + String.valueOf(result.getOriginalIntent().getIntExtra("ITEM_ID",0)), Toast.LENGTH_LONG).show();
}

Starting react-native activity from java module (android)

I see that you can bring your activity form the background to the foreground in android using the following lines
Intent intent = new Intent(this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
Now the problem is I don't know how to get the name of the react activity to work - When I try to compile I get
error: cannot find symbol Intent i = new Intent(mReactContext,
MainActivity.class);
symbol: class MainActivity
I'm not very experienced with java - so this is part of my problem, I tried using getCurrentActivity() - but this doesn't seem to work either.
Anyone has an idea?
Thanks!

If you have access to reactContext (I see you have) you can try this:
Context context = getReactApplicationContext();
String pn = context.getApplicationContext().getPackageName();
Intent li = context.getPackageManager().getLaunchIntentForPackage(pn);
context.startActivity(li);
String pn is just a package name (e.g. "com.yourapp"), so you can skip getPackageName() and just pass your package name to getLaunchIntentForPackager(). You can check this solution on react-native-system-notification

You should get reference of your first activity. Then Create your intent and start activity. Run the code below somewhere in your code(for example in a react method which triggers an activity)
Activity currentActivity = getCurrentActivity();
Intent intent = new Intent(name of your activity);
currentActivity.startActivityForResult(intent,FLAG_ACTIVITY_NEW_TASK
);
// create onActivityResult method to process your task according to result
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == FLAG_ACTIVITY_NEW_TASK ) {
// do your job
}
}
It seems you use MainActivity.class as parameter in intent. I'm not an expert but it seems wrong. In a react-native project mainactivity will be triggered automatically and index.android.js will be called. You can use an activity you create as well you don't have to use native android activities like Intent.ACTION_GET_CONTENT which can be used to get information of an image from gallery.

How to pass String from 2 activities to one?

I have two activitys with lists.
One for tablet's and one for regular density phones.
When an item in the list is clicked it launches the same activity for either activity with list's.
The problem is when an item is clicked i have getter and setter class that gets the URL for a particular item and passes it to the launching activity like this...
private String URL = null;
try{
URL = com.fttech.AbstractFeedsActivity.feed_url;
}
catch(IllegalArgumentException e){
e.printStackTrace();
URL = com.fttech.ItemsActivity.url;
}
As you see what i tried to do is try and catch.
So if the first one isnt found then the second one will be retrieved.
But it doesnt seem to work.
It returns null each time.
For what i have describe what is the best way to implement this?
Is my way logic? Or is there a better way.
Thanks

Try this,
private String URL = null;
try{
URL = com.fttech.AbstractFeedsActivity.feed_url;
if(TextUtils.isEmpty(URL)){
URL = com.fttech.ItemsActivity.url;
// Pass this URL
}
else{
// If its not empty then it will pass the first URL
}
}
catch(IllegalArgumentException e){
e.printStackTrace();
}

No need to pass String to 2 activities, if you want to just pass strings to one or as many activities as you want, just put them in SharedPreferences or declare a variable in static class and then set/get it whenever you want.

Passing values from one Activity to another:
Intent intent = new Intent(context, CalledActivity.class);
intent.putExtra(key, value);
startActivity(intent);
If you want some data back from called Activity then you can use startActivityForResult() as:
Intent intent = new Intent(context, CalledActivity.class);
intent.putExtra(key, value);
startActivityForResult(intent, requestCode);
In called activity you can set data as:
setResult(RESULT_OK, intent);
Note: Here you set the value in intent and pass it to setResult().
On returning back to calling Activity you can get data by overriding:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == RESULT_OK){
//Get data from Intent "data" and do your task here....
}
}
Note: You can pass primitive data type values thru Intent and if you want to pass other types then you have to use Bundle like this.
Bundle data = new Bundle();
data.putIntArray(key, value);
//same way you can set other values.......
//Now set this Bundle value to Intent as you do for primitive type....
Intent intent = new Intent(context, CalledActivity.class);
intent.putExtra(data);
startActivity(intent);
Receiving data in Activity:
//For primitive values:
DataType var_name = getIntent().getExtras().get(key);
//For Bundle values:
Bundle var_name = getIntent().getExtras().getBundle(key);

Android: Passing data between activities - multiple intent.putExtra not working?

Having a very annoying problem with passing data between activities.
This is the code I use to successfully pass the value of a progress bar to a different activity:
public void WhenClicked(View view)
{
view.clearAnimation();
Intent intent = new Intent("com.android.Test.QUESTION");
if (progressBar != null)
{
if (progressBar.getProgress() != 0)
{
intent.putExtra("ProgressBarValue", progressBar.getProgress());
}
}
startActivity(intent);
}
Okay, so that worked. Now, when I change it to this, it blows up:
public void WhenClicked(View view, String category)
{
view.clearAnimation();
Intent intent = new Intent("com.android.Test.QUESTION");
intent.putExtra("Category", category);
if (progressBar != null)
{
if (progressBar.getProgress() != 0)
{
intent.putExtra("ProgressBarValue", progressBar.getProgress());
}
}
startActivity(intent);
}
I don't understand what the problem is. I've even tried sticking it all into a bundle and adding the bundle as an extra - that just made it crash as well. Maybe I'm being stupid and I've just been staring at my code too long, but any help would be great!
This is my first time with Android and it's killing me!
Thanks in advance guys!

first you need to create bundle object(Bundle bnd=new Bundle();) and next bnd.putString("param1", "test");
next create intent:
Intent myIntent = new Intent(current classname.this,nextactivity.class);
myIntent.putExtras(bnd);
startActivityForResult(myIntent, 0);
In 2nd activity u need to get bundel value like :
Bundle bundle = this.getIntent().getExtras();
String _getData=bundle.getString("param1");

Assuming that you have an activity called QUESTION, you might try to put .class on the end as well as "this" for first param:
Intent intent = new Intent(this, QUESTION.class);
if you don't have a QUESTION activity then that is another problem. I'm assuming your activities are in the same app?

I believe, the activity which should handle this intent action com.android.Test.QUESTION does not understand your category i.e intent.putExtra("Category", category);.
You can try fixing it in 2 ways:
If the receiving activity is from your own application, then try using explicit intent i.e Intent intent = new Intent("youCurrentClass","theClassYouWantToCall"); without feeding additional category, this will launch the specified activity. In case of explicit Intent Android system does not do a comparison with the intent-filters to match Intent Object.
Change the category section in relation to intent receiving Activity.
Hope this helps,
sku