application全局变量

注意添加application android:name="YourAppName"
 public class YourAppName extends Application {
  private List<Item> mItems;

  @Override
  public void onCreate() {
    super.onCreate();
    mItems = getYourItemList();
  }

  public List<Item> getItems() {
    return mItems;
  }
}

 

public class DetailActivity extends Activity {
  private YourAppName mApp;
  private ImageButton mNextButton;
  private ImageButton mBackButton;
  private TextView mTitle;
  private int mIndex;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_layout);
    mApp = (YourAppName) getApplication();

    /*This index should come from the intent */
    mIndex = 2; 
    getWidgets();
    populateWidgets();
  }

  private void getWidgets() {
    mNextButton = (ImageButton)findViewById(R.id.next);
    mTitle = (TextView)findViewById(R.id.title);
    /* other findViewById */

    mNextButton.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
           mIndex++; /*Notice that this will get a NPE.
                     You need to place a better logic here */
           populateWidgets();
        }
    });
  }

  private void populateWidgets() {
    Item item = mApp.getItemList().get(mItem);
    mTitle.setText(item.getName());
  }
}