How to pass values from one activity to another in android studio - android-studio

Question

I'm new to android studio, I came across this multiple contact picker and I want to get phone numbers in 1st activity and in the 2nd activity send messages to those selected numbers.
In my first activity I have -
new MultiContactPicker.Builder(MainActivity.this) //Activity/fragment context
.theme(R.style.MyCustomPickerTheme) //Optional - default: MultiContactPicker.Azure
.hideScrollbar(false) //Optional - default: false
.showTrack(true) //Optional - default: true
.searchIconColor(Color.WHITE) //Option - default: White
.setChoiceMode(MultiContactPicker.CHOICE_MODE_MULTIPLE) //Optional - default: CHOICE_MODE_MULTIPLE
.handleColor(ContextCompat.getColor(MainActivity.this, R.color.colorPrimary)) //Optional - default: Azure Blue
.bubbleColor(ContextCompat.getColor(MainActivity.this, R.color.colorPrimary)) //Optional - default: Azure Blue
.bubbleTextColor(Color.WHITE) //Optional - default: White
.setTitleText("Select Contacts") //Optional - default: Select Contacts
.setSelectedContacts("10", "5" / myList) //Optional - will pre-select contacts of your choice. String... or List<ContactResult>
.setLoadingType(MultiContactPicker.LOAD_ASYNC) //Optional - default LOAD_ASYNC (wait till all loaded vs stream results)
.limitToColumn(LimitColumn.NONE) //Optional - default NONE (Include phone + email, limiting to one can improve loading time)
.setActivityAnimations(android.R.anim.fade_in, android.R.anim.fade_out,
android.R.anim.fade_in,
android.R.anim.fade_out) //Optional - default: No animation overrides
.showPickerForResult(CONTACT_PICKER_REQUEST);
The numbers get stored in results which is also in 1st activity -
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == CONTACT_PICKER_REQUEST){
if(resultCode == RESULT_OK) {
List<ContactResult> results = MultiContactPicker.obtainResult(data);
Log.d("MyTag", results.get(0).getDisplayName());
} else if(resultCode == RESULT_CANCELED){
System.out.println("User closed the picker without selecting items.");
}
}
}
I called the results in 2nd activity -
List<ContactResult> results = new ArrayList<>();
But when I print the output, it doesn't give any. How can I get it right. Thanks in advance.

Answer 1

You can set up intents when you are starting a new activity. Intents are a way to pass values from your current activity to the next and I'd suggest you learn the basics uses for them. Here's official documentation you can check out: https://developer.android.com/guide/components/intents-filters
When you start the other activity you can code the Intent like this:
//Code to start an activity
Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
intent.putExtra("id", "YOUR_VALUE1");
intent.putExtra("title", "YOUR_VALUE2");
startActivity(intent);
On the SecondActivity.class you will get can then assign your value to a variable:
//Code on your second activity
public class FollowersActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Intent intent = getIntent();
String id = intent.getStringExtra("id");
String title = intent.getStringExtra("title");
//id will equal "YOUR_VALUE1"
//title will equal "YOUR_VALUE2"

Answer 2

First activity sent your data:-
// if you want to send on selected position data than pass position in place of zero (0).
Inent intent = new Intent(this, SecondActivity.class)
intent.putExtra("name", results.get(0).getName());
intent.putExtra("number", results.get(0).getNumber());
startActivity(intent)
// if you want to send the all the list in second activity using intent than
Intent intent = new Intent(this,SecondActivity.class);
Bundle bundle = new Bundle();
bundle.putParcelable("data", results);
intent.putExtras(bundle);
startActivity(intent);
Second activity get your data:-
// retrive selected position data
Intent intent = new Intent();
String name = intent.getStringExtra("name").toString();
String number = intent.getStringExtra("number").toString();
tv_name2.setText(name);
tv_number.setText(number);
// retrive result list from intent
Bundle bundle = getIntent().getExtras();
sharedBookingObject = bundle.getParcelable("data");
hope this answer will helpful for you...