How to start new activity on button click

Question

In an Android application, how do you start a new activity (GUI) when a button in another activity is clicked, and how do you pass data between these two activities?

Answer 1

Easy.

Intent myIntent = new Intent(CurrentActivity.this, NextActivity.class);
myIntent.putExtra("key", value); //Optional parameters
CurrentActivity.this.startActivity(myIntent);

Extras are retrieved on the other side via:

@Override
protected void onCreate(Bundle savedInstanceState) {
    Intent intent = getIntent();
    String value = intent.getStringExtra("key"); //if it's a string you stored.
}

Don't forget to add your new activity in the AndroidManifest.xml: