Problems sending data from one activity to another with application

Question

As the title says I want to transfer data, in this case the information introduced by the user on an EditText and a Spinner, from one activity to another.

I am following a tutorial from a book but it doesn't work (I think its not complete). Here the code of the program:

    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setContentView(R.layout.main);
    this.location=(EditText)findViewById(R.id.location);
    this.cuisine=(Spinner)findViewById(R.id.cuisine);
    this.grabReviews=(Button)findViewById(R.id.get_reviews_button);

    ArrayAdapter adapter = ArrayAdapter.createFromResource(this, R.array.cuisine, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    this.cuisine.setAdapter(adapter);
    this.grabReviews.setOnClickListener(new OnClickListener()
        {
            public void onClick(View v)
            {
                handleGetReviews();
            }
        }
    );
}

private void handleGetReviews() {

    RestaurantsActivity application= (RestaurantsActivity) getApplication();
    application.setReviewCriteriaCuisine(this.cuisine.getSelectedItem().toString());
    application.setReviewCriteriaLocation(this.location.getText().toString());
    Intent intent=new Intent(Constants.INTENT_ACTION_VIEW_LIST);
    startActivity(intent);

}

This code above doesn't work. I dont understand four things:

-RestaurantsActivity must be the actual activity right?

-In all the examples I have seen over the internet there is an application extends class, in this example there isnt.

-setReviewCriteria function is missing

-Where does Constants.INTENT_ACTION_VIEW_LIST come from ?

Answer 1

So your target is to get the data to Restaurantsactivity? Normally data in android are handed over from one activtiy to another by using Intents.

So first you create an intent. Then you put the data you want to transfer into the intent by using the intent.putExtra() method. In the activity that gets the intent you can get the data by using getIntent().getExtra() method (getExtra can be something like getStringExtra()).

Here is a small example for a edit box called "name":

public void onCreate(Bundle iBundle){
  //do some stuff here
  //perhaps define some Buttos and so on

  //now lets start the activity
  Intent intent = new Intent(currentActivityname.this, ActivityYouWantToStart.class);
  intent.putExtra("name", name.getText().toString())
  startActivity(intent); // you can also start an startActivityForResult() here :)
}

In our receiving activity you can now handle the intent (e.g. in the onCreate() method

public void onCreate(Bundle iBundle){
String name = this.getIntent().getStringExtra("name",some default value);
}