Android, Can I use putExtra to pass multiple values

Question

I want to pass two values to another activity can I do this with putExtra or do I have to do it a more complicated way, which it seems from my reading. E.g.. can something l

Answer 1

For a single small amount of value putExtra is perfect but when you pass multiple values and need to pass custom ArrayList or List then I think it's a bad idea. Solution is you can use Parcelable. You and also use Singleton or Serializable also.

Parcelable:

Parcelable class which you need to share.

 public class MyParcelable implements Parcelable {
     private int mData;

     public int describeContents() {
         return 0;
     }

     public void writeToParcel(Parcel out, int flags) {
         out.writeInt(mData);
     }

     public static final Parcelable.Creator<MyParcelable> CREATOR
             = new Parcelable.Creator<MyParcelable>() {
         public MyParcelable createFromParcel(Parcel in) {
             return new MyParcelable(in);
         }

         public MyParcelable[] newArray(int size) {
             return new MyParcelable[size];
         }
     };

     private MyParcelable(Parcel in) {
         mData = in.readInt();
     }
 }

Form your activity where you want to send

MyParcelable example = new MyParcelable();
.....
.....
Bundle bundle = new Bundle();
bundle.putParcelable("example", Parcels.wrap(example));

From another activity where you want to receive

MyParcelable example = Parcels.unwrap(getIntent().getParcelableExtra("example"));

Answer 2

No you can't but you can pass an array using:

public Intent putExtra (String name, String[] value)

like this for example:

i.putExtra(ID_EXTRA, new String[]{"1", "111"});

Answer 3

You could pass a 'bundle' of extras rather than individual extras if you like, for example:-

Intent intent = new Intent(this, MyActivity.class);
Bundle extras = new Bundle();
extras.putString("EXTRA_USERNAME","my_username");
extras.putString("EXTRA_PASSWORD","my_password");
intent.putExtras(extras);
startActivity(intent);

Then in your Activity that your triggering, you can reference these like so:-

Intent intent = getIntent();
Bundle extras = intent.getExtras();
String username_string = extras.getString("EXTRA_USERNAME");
String password_string = extras.getString("EXTRA_PASSWORD");

Or (if you prefer):-

Bundle extras = getIntent().getExtras();
String username_string = extras.getString("EXTRA_USERNAME");
String password_string = extras.getString("EXTRA_PASSWORD");

Hope this helps! :-)

Answer 4

Your example won't work, since the Extras are made out of a Key and a Value. You cant put multiple Keys and Values in one Extra

Also, your keys need to be Strings as far as I know (and noticed) but I might be wrong on that one.

Try this:

public final static String ID_EXTRA="com.fnesse.beachguide._ID";

Intent i = new Intent(this, CoastList.class);
i.putExtra("ID_Extra", ID_EXTRA);
i.putExtra("1", 111);
startActivity(i);

Answer 5

Putting extra values in class

public class MainActivity extends Activity {
        public final static String USERNAME = "com.example.myfirstapp.MESSAGE";
        public final static String EMAIL = "com.example.myfirstapp.EMAIL";

public void registerUser(View view) {
        Intent intent = new Intent(this, DisplayMessageActivity.class);
        EditText userNameTxt = (EditText) findViewById(R.id.editText1);
        EditText emailTxt = (EditText) findViewById(R.id.editText2);
        String userName = userNameTxt.getText().toString();
        String email = emailTxt.getText().toString();
        intent.putExtra(USERNAME, userName);
        intent.putExtra(EMAIL,email);
        startActivity(intent);

    }

Reading extra values from another class

public class DisplayMessageActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent intent = getIntent();
        String user = intent.getStringExtra(MainActivity.USERNAME);
        String email = intent.getStringExtra(MainActivity.EMAIL);   

Answer 6

You can pass multiple values by using multiple keys. Instead of

i.putExtra(ID_EXTRA, "1", "111");

do

i.putExtra(ID_EXTRA1, "1");
i.putExtra(ID_EXTRA2, "111");

Of course you have to define 2 constants for the keys and have to read both seperately in the new activity.

Or you can pass a string array via

i.putExtra(ID_EXTRA, new String[] { "1", "111"});