我有TabActivity
个标签。有一个异步任务,当通过单击菜单项进行刷新运行时,从服务器检索更新的数据。此数据存储在控制器中,并由所有视图访问,因此模型只需加载一次。
我的问题是,在运行异步活动并更新模型后,如何通知所有三个标签以更新其内容?
我的活动
public class DashboardActivity extends TabActivity {
private ProfileModel profile;
private TabHost tabHost;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
profile = Controller.getProfile();
this.setContentView(R.layout.dashboard);
tabHost = getTabHost();
setupTab(new TextView(this), "Home", new Intent().setClass(DashboardActivity.this, HomeActivity.class));
setupTab(new TextView(this), "History", new Intent().setClass(DashboardActivity.this, PaymentsActivity.class));
setupTab(new TextView(this), "My Wallet", new Intent().setClass(DashboardActivity.this, MyWalletActivity.class));
tabHost.setCurrentTab(0);
ActionBar actionBar = (ActionBar)findViewById(R.id.actionbar);
actionBar.setTitle(profile.Name);
}
private void setupTab(final View view, final String tag, Intent content) {
View tabview = createTabView(tabHost.getContext(), tag);
TabSpec setContent = tabHost.newTabSpec(tag)
.setIndicator(tabview)
.setContent(content);
tabHost.addTab(setContent);
}
private static View createTabView(final Context context, final String text) {
View view = LayoutInflater.from(context).inflate(R.layout.tabs_bg, null);
TextView tv = (TextView) view.findViewById(R.id.tabsText);
tv.setText(text);
return view;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.mainmenu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.menu_settings:
return true;
case R.id.menu_refresh:
new RefreshDashboardTask().execute();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private class RefreshDashboardTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute()
{
ActionBar actionBar = (ActionBar)findViewById(R.id.actionbar);
if(actionBar != null)
actionBar.setProgressBarVisibility(View.VISIBLE);
}
@Override
protected Void doInBackground(Void... params)
{
try {
profile = DataHelper.getProfile();
Controller.setProfile(profile);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (HttpException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ServerException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result)
{
ActionBar actionBar = (ActionBar)findViewById(R.id.actionbar);
if(actionBar != null)
actionBar.setProgressBarVisibility(View.GONE);
}
}
}
编辑为了进一步详细说明,这里还有一些代码。
我的控制器
public class Controller extends Application {
private static Controller instance;
private static DefaultHttpClient client;
private static ProfileModel profile;
public Controller() {
instance = this;
client = new DefaultHttpClient();
profile = null;
}
public static Context getContext() {
return instance;
}
public static DefaultHttpClient getHttpContext() {
return client;
}
public static ProfileModel getProfile() {
return profile;
}
public static void setProfile(ProfileModel profile) {
Controller.profile = profile;
}
@Override
public void onCreate()
{
super.onCreate();
}
}
我在标签视图中的一项活动。这个是最简单的一个,因为它只是一个列表。主视图是2个列表,由标题分隔,钱包视图是动态生成的列表,带有标题,从集合中的集合创建。
public class PaymentsActivity extends Activity {
ProfileModel profile;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.payment_history);
profile = Controller.getProfile();
ListView itemList = (ListView)this.findViewById(R.id.payment_history_list);
itemList.setTextFilterEnabled(true);
itemList.clearChoices();
itemList.setAdapter(new ItemSummaryAdapter(PaymentsActivity.this, R.layout.list_item_payment, profile.Items));
//statementList.setOnItemClickListener(clickListener);
}
}
此处的目标是刷新按钮更新控制器中的数据。选项卡内的所有视图都会更新。
答案 0 :(得分:3)
更新:
如果我是你,我会Observer pattern。首先,向Controller类添加一组侦听器:
public class Controller extends Application {
private static Controller instance;
private static DefaultHttpClient client;
private static ProfileModel profile;
private static Set<ControllerUpdateListener> updateListeners = new HashSet<ControllerUpdateListener>();
//...
public static void addListener(ControllerUpdateListener listener)
{
updateListeners.add(listener);
}
public static interface ControllerUpdateListener {
void onControllerUpdate(ProfileModel model);
}
}
然后让您的各个标签活动实施ControllerUpdateListener
。最后,将触发器添加到Controller
类:
public static void setProfile(ProfileModel profile) {
Controller.profile = profile;
for(ControllerUpdateListener l : updateListeners) {
l.onControllerUpdate(profile);
}
}
不要忘记将每个活动注册为Controller
public class PaymentsActivity extends Activity implements Controller.ControllerUpdateListener {
ProfileModel profile;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.payment_history);
Controller.addListener(this); // <-- Don't forget this...
profile = Controller.getProfile();
ListView itemList = (ListView)this.findViewById(R.id.payment_history_list);
itemList.setTextFilterEnabled(true);
itemList.clearChoices();
itemList.setAdapter(new ItemSummaryAdapter(PaymentsActivity.this, R.layout.list_item_payment, profile.Items));
//statementList.setOnItemClickListener(clickListener);
}
public void onControllerUpdate(ProfileModel model) {
//update these views...
}
}
现在,您的每个标签活动都应在notifyDataSetChanged()
方法中触发onControllerUpdate(ProfileModel)
(或其他任何触发更新的方法)。
答案 1 :(得分:2)
在刷新视图中的内容后,是否在适配器上调用notifyDataSetChanged()?如果它是一个ListView,那么只是通知适配器应该触发刷新。这实际上是你应该处理ListView中的行的唯一方法。