How do I pass data between Activities in Android a

Question

I have a scenario where, after logging in through a login page, there will be a sign-out button on each activity.

On clicking sign-out, I will be passing the session id of the signed in user to sign-out. Can anyone guide me on how to keep session id available to all activities?

Any alternative to this case

Answer 1

Intent intent = new Intent(YourCurrentActivity.this, YourActivityName.class);
intent.putExtra("NAme","John");
intent.putExtra("Id",1);
startActivity(intent);

You can retrieve it in another activity. Two ways:

int id = getIntent.getIntExtra("id", /* defaltvalue */ 2);

The second way is:

Intent i = getIntent();
String name = i.getStringExtra("name");

Answer 2

Kotlin

Pass from First Activity

val intent = Intent(this, SecondActivity::class.java)
intent.putExtra("key", "value")
startActivity(intent)

Get in Second Activity

val value = getIntent().getStringExtra("key")

Suggestion

Always put keys in constant file for more managed way.

companion object {
    val KEY = "key"
}

Answer 3

It helps me to see things in context. Here are two examples.

Passing Data Forward

Main Activity

• Put the data you want to send in an Intent with a key-value pair. See this answer for naming conventions for the key.
• Start the Second Activity with startActivity.

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    // "Go to Second Activity" button click
    public void onButtonClick(View view) {

        // get the text to pass
        EditText editText = (EditText) findViewById(R.id.editText);
        String textToPass = editText.getText().toString();

        // start the SecondActivity
        Intent intent = new Intent(this, SecondActivity.class);
        intent.putExtra(Intent.EXTRA_TEXT, textToPass);
        startActivity(intent);
    }
}

Second Activity

• You use getIntent() to get the Intent that started the second activity. Then you can extract the data with getExtras() and the key you defined in the first activity. Since our data is a String we will just use getStringExtra here.

SecondActivity.java

public class SecondActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);

        // get the text from MainActivity
        Intent intent = getIntent();
        String text = intent.getStringExtra(Intent.EXTRA_TEXT);

        // use the text in a TextView
        TextView textView = (TextView) findViewById(R.id.textView);
        textView.setText(text);
    }
}

Passing Data Back

Main Activity

• Start the Second Activity with startActivityForResult, providing it an arbitrary result code.
• Override onActivityResult. This is called when the Second Activity finishes. You can make sure that it is actually the Second Activity by checking the result code. (This is useful when you are starting multiple different activities from the same main activity.)
• Extract the data you got from the return Intent. The data is extracted using a key-value pair. I could use any string for the key but I'll use the predefined Intent.EXTRA_TEXT since I'm sending text.

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private static final int SECOND_ACTIVITY_REQUEST_CODE = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    // "Go to Second Activity" button click
    public void onButtonClick(View view) {

        // Start the SecondActivity
        Intent intent = new Intent(this, SecondActivity.class);
        startActivityForResult(intent, SECOND_ACTIVITY_REQUEST_CODE);
    }

    // This method is called when the second activity finishes
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        // check that it is the SecondActivity with an OK result
        if (requestCode == SECOND_ACTIVITY_REQUEST_CODE) {
            if (resultCode == RESULT_OK) {

                // get String data from Intent
                String returnString = data.getStringExtra(Intent.EXTRA_TEXT);

                // set text view with string
                TextView textView = (TextView) findViewById(R.id.textView);
                textView.setText(returnString);
            }
        }
    }
}

Second Activity

• Put the data that you want to send back to the previous activity into an Intent. The data is stored in the Intent using a key-value pair. I chose to use Intent.EXTRA_TEXT for my key.
• Set the result to RESULT_OK and add the intent holding your data.
• Call finish() to close the Second Activity.

SecondActivity.java

public class SecondActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
    }

    // "Send text back" button click
    public void onButtonClick(View view) {

        // get the text from the EditText
        EditText editText = (EditText) findViewById(R.id.editText);
        String stringToPassBack = editText.getText().toString();

        // put the String to pass back into an Intent and close this activity
        Intent intent = new Intent();
        intent.putExtra(Intent.EXTRA_TEXT, stringToPassBack);
        setResult(RESULT_OK, intent);
        finish();
    }
}

Answer 4

The easiest way to do this would be to pass the session id to the signout activity in the Intent you're using to start the activity:

Intent intent = new Intent(getBaseContext(), SignoutActivity.class);
intent.putExtra("EXTRA_SESSION_ID", sessionId);
startActivity(intent);

Access that intent on next activity:

String sessionId = getIntent().getStringExtra("EXTRA_SESSION_ID");

The docs for Intents has more information (look at the section titled "Extras").

Answer 5

Source class:

Intent myIntent = new Intent(this, NewActivity.class);
myIntent.putExtra("firstName", "Your First Name Here");
myIntent.putExtra("lastName", "Your Last Name Here");
startActivity(myIntent)

Destination Class (NewActivity class):

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view);

    Intent intent = getIntent();

    String fName = intent.getStringExtra("firstName");
    String lName = intent.getStringExtra("lastName");
}

Answer 6

You can also pass custom class objects by making a parcelable class. Best way to make it parcelable is to write your class and then simply paste it to a site like http://www.parcelabler.com/. Click on build and you will get new code. Copy all of this and replace the original class contents. Then-

Intent intent = new Intent(getBaseContext(), NextActivity.class);
Foo foo = new Foo();
intent.putExtra("foo", foo);
startActivity(intent);

and get the result in NextActivity like-

Foo foo = getIntent().getExtras().getParcelable("foo");

Now you can simply use the foo object like you would have used.