8. Context
Interface to global information about an
application environment.
Up-calls for application-level operations such
as launching activities, broadcasting and
receiving intents, etc.
9. Context examples
TextView text = new TextView(context);
new ArrayAdapter(context, R.layout.item, myList)
context.getExternalCacheDir()
context.getResources()
context.startActivity(navigationIntent)
10. R.java
public class TestActivity extends Activity {
@Override
protected void onCreate(Bundle savedState) {
super.onCreate(savedState);
setContentView(R.layout.main);
}
}
28. AdapterView
Gallery gallery = (Gallery) findViewById(R.id.gallery);
ArrayList<String> list = new ArrayList<String>();
gallery.setAdapter(new ArrayAdapter<String>(this, 0, list){
@Override
public View getView(int position, View convertView,
ViewGroup parent) {
// 1. Check if view already exists
// 2. If not - Inflate view
// 3. Populate view
return view;
}
});
29. Intent
Abstract description of an operation to be performed.
External Intents
Open URL
Call a Person
Share an Image
Internal Intents
Start Activity
30. Example
Intent intent = new Intent(context, SecondActivity.class);
startActivity(intent);
Intent intent = new Intent(context, SecondActivity.class);
intent.putExtra("url", url);
intent.putExtra("bean", serializable);
startActivity(intent);
31. Example
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.article_detail);
String s = getIntent().getStringExtra("url");
Bean b = (Bean)getIntent().getSerializableExtra("bean");
}