Android How-To: Create Spinners, ListViews and Context Menues programmatically

An Android user interface is created by specifying a layout XML usually, but sometimes you need to create your interfaces or parts of it "on-the-fly" in your programm code. This is not very easy sometimes because of the lack of documentation. The following code snippets show you how I could create a Spinner and a ListView widget programmatically:

...
public class Sample extends Activity
  ...
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    ...
    
    //Creating a spinner
    Spinner spinner = new Spinner(this);
    ArrayAdapter spinnerArrayAdapter = new ArrayAdapter(this,
        android.R.layout.simple_spinner_dropdown_item,
            new String[] { "Apple", "Peach", "Banana" });
    spinner.setAdapter(spinnerArrayAdapter);

    
    //Add spinner to this activity's view (a LinearLayout)
    mainLayout.addView(spinner, new LinearLayout.LayoutParams(
        LinearLayout.LayoutParams.WRAP_CONTENT,
        LinearLayout.LayoutParams.WRAP_CONTENT));
    ...
  }
}

...
public class Sample extends Activity
  ...
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    ...
    
    //Creating a ListView with Context Menu
    ListView listView = new ListView(this);
    ArrayAdapter listViewArrayAdapter =
        new ArrayAdapter(this,
           android.R.layout.simple_list_item_1, new String[] {
            "Apple", "Peach","Banane" });
    listView.setAdapter(listViewArrayAdapter);
    listView.setFocusableInTouchMode(true);
    listView.setOnFocusChangeListener(
        new View.OnFocusChangeListener() {
      @Override
      public void onFocusChange(View arg0, boolean arg1) {
        Log.i("SampleApp", "onFocusChanged() - view=" + arg0);
      }
    });
    listView.setOnItemClickListener(
        new AdapterView.OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView adapterView, View view,
          int arg2, long arg3) {
        int selectedPosition = adapterView.getSelectedItemPosition();
        Log.i("SampleApp", "Click on position"+selectedPosition);
      }
    });
    listView
        .setOnCreateContextMenuListener(
            new View.OnCreateContextMenuListener() {

          public void onCreateContextMenu(ContextMenu menu, View view,
              ContextMenu.ContextMenuInfo menuInfo) {
            AdapterContextMenuInfo mi =
                (AdapterContextMenuInfo) menuInfo;
            menu.add(0, 0, 0, "Context-Menu-Entry");
          }

    });
    ...
  }
}