如何更新ViewPager使用的片段的数据？查看未显示更新后的数据数据、片段、ViewPager
我知道，同样的问题已经被问了很多次，但我没有能够解决我的问题。
I know the same question has been asked so many times but I am not able to solve my issue.
我已经创建了一个活动具有 ViewPager 里面应该有4 页面。
I have created an Activity which has a ViewPager which should have 4 Pages.
我使用的是相同的片段的所有网页。该片段有一个的GridView 每当我刷到其他网页应更新。
I am using the same Fragment for all pages. The Fragment has a GridView which should be updated whenever I swipe to the other page.
以下是类和放大器; XML布局我已经使用来创建它。
Following are the classes & XML layouts I have used to create it.
活动的布局 activity_discover.xml
<android.support.v4.view.ViewPager
android:id="@+id/activity_discover_view_pager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip" >
<android.support.v4.view.PagerTabStrip
android:id="@+id/activity_discover_pager_tab_strip"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/white"
android:textColor="@color/black"
android:textSize="@dimen/header_text" />
</android.support.v4.view.ViewPager>
</RelativeLayout>
活动 DiscoverActivity.java
public class DiscoverActivity extends FragmentActivity implements OnClickListener, OnPageChangeListener
{
private final static String TAG = "DiscoverActivity";
private UtilDialog utilDialog;
MPagerAdapter adapterViewPager;
PagerTabStrip pagerTabStrip;
ViewPager viewPager;
public ArrayList<String> listCategory;
LMProgressDialog progressDialog;
private RelativeLayout relativeCountry;
private RelativeLayout relativeCity;
private TextView tvCountry;
private TextView tvCity;
private String selectedCategory;
private int selectedCityID = 0;
private int selectedCategoryID = 0;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_discover);
initParameters();
initView();
}
void initParameters()
{
progressDialog = new LMProgressDialog(this);
utilDialog = new UtilDialog(this);
preferences = PreferenceManager.getDefaultSharedPreferences(this);
editor = preferences.edit();
editor.commit();
selectedCategory = getResources().getString(R.string.adventure);
listCategory = new ArrayList<String>();
listCategory.add(getResources().getString(R.string.adventure));
listCategory.add(getResources().getString(R.string.night_life));
listCategory.add(getResources().getString(R.string.life_styles));
listCategory.add(getResources().getString(R.string.events));
}
void initView()
{
viewPager = (ViewPager) findViewById(R.id.activity_discover_view_pager);
viewPager.setOnPageChangeListener(this);
adapterViewPager = new MPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(adapterViewPager);
pagerTabStrip = (PagerTabStrip) findViewById(R.id.activity_discover_pager_tab_strip);
pagerTabStrip.setTabIndicatorColor(getResources().getColor(R.color.white));
}
@Override
protected void onDestroy()
{
super.onDestroy();
}
public class MPagerAdapter extends FragmentPagerAdapter
{
private Map<Integer, String> mFragmentTags;
private FragmentManager mFragmentManager;
public MPagerAdapter(FragmentManager fm)
{
super(fm);
mFragmentManager = fm;
mFragmentTags = new HashMap<Integer, String>();
}
@Override
public int getCount()
{
return 4;
}
@Override
public Fragment getItem(int position)
{
Fragment fragment = Fragment.instantiate(DiscoverActivity.this,
FragmentMediaContent.class.getName(), null);
return fragment;
}
@Override
public Object instantiateItem(ViewGroup container, int position)
{
Object obj = super.instantiateItem(container, position);
if (obj instanceof Fragment)
{
// record the fragment tag here.
Fragment f = (Fragment) obj;
String tag = f.getTag();
mFragmentTags.put(position, tag);
}
return obj;
}
public Fragment getFragment(int position)
{
String tag = mFragmentTags.get(position);
if (tag == null)
return null;
return mFragmentManager.findFragmentByTag(tag);
}
@Override
public CharSequence getPageTitle(int position)
{
return listCategory.get(position).toString().toUpperCase();
}
}
@Override
public void onPageScrollStateChanged(int arg0)
{
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2)
{
}
@Override
public void onPageSelected(int position)
{
selectedCategoryID = position;
selectedCategory = listCategory.get(position);
try
{
JSONObject jsonObject = new JSONObject();
jsonObject.put(Constants.CITY_ID, selectedCityID);
jsonObject.put(Constants.CATEGORY, selectedCategory);
makeJsonObjectRequest(Request.Method.POST, jsonObject, API.URL_LOAD_MEDIA);
} catch (JSONException e)
{
e.printStackTrace();
}
}
void prepareMediaList(JSONArray arrayMedia)
{
int noOfMedia = arrayMedia.length();
ArrayList<MediaType> listMedia = new ArrayList<MediaType>();
for (int i = 0; i < noOfMedia; i++)
{
try
{
JSONObject objectMedia = arrayMedia.getJSONObject(i);
int id = objectMedia.getInt(Constants.ID);
String category = objectMedia.getString(Constants.CATEGORY);
String mediaType = objectMedia.getString(Constants.MEDIA_TYPE);
int cityID = objectMedia.getInt(Constants.CITIES_ID);
String path = objectMedia.getString(Constants.PATH);
String thumbnailPath = objectMedia.getString(Constants.THUMBNAIL_PATH);
String description = objectMedia.getString(Constants.DESCRIPTION);
int userID = objectMedia.getInt(Constants.USERS_ID);
listMedia.add(new MediaType(id, mediaType, path, category, userID, cityID, 0, description, thumbnailPath));
} catch (JSONException e)
{
e.printStackTrace();
}
}
FragmentMediaContent fragment = (FragmentMediaContent) adapterViewPager.getFragment(selectedCategoryID);
Log.i(TAG, "fragment: " + fragment);
fragment.updateData(listMedia, selectedCategory);
}
}
片段类 FragmentMediaContent.java ：
public class FragmentMediaContent extends Fragment
{
private final static String TAG = "FragmentMediaContent";
public static final String FRAGMENT_POSITION = null;
private GridView gridView;
private UtilDialog utilDialog;
private SharedPreferences preferences;
private Editor editor;
private ArrayList<MediaType> listMedia;
MediaAdapter mediaAdapter;
private int cityID;
private String category;
LMProgressDialog progressDialog;
TextView tvTest;
public static FragmentMediaContent newInstance(int num)
{
FragmentMediaContent f = new FragmentMediaContent();
return f;
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)
{
return inflater.inflate(R.layout.fragment_media_content, container, false);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState)
{
super.onViewCreated(view, savedInstanceState);
initParameters();
initViews();
}
void initParameters()
{
getSize();
listMedia = new ArrayList<MediaType>();
utilDialog = new UtilDialog(getActivity());
progressDialog = new LMProgressDialog(getActivity());
preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
editor = preferences.edit();
mediaAdapter = new MediaAdapter(getActivity(), listMedia);
}
void initViews()
{
tvTest = (TextView) getActivity().findViewById(R.id.fragment_media_content_tv_test);
tvTest.setText(category+" no of media");
tvTest.setVisibility(View.GONE);
gridView = (GridView) getActivity().findViewById(R.id.fragment_media_content_grid_view);
gridView.setAdapter(mediaAdapter);
}
/**
* MediaAdapter : ArrayAdapter class which prepares view for list of
* MediaType.
*
*/
class MediaAdapter extends ArrayAdapter<MediaType>
{
MediaAdapter(Context context, ArrayList<MediaType> list)
{
super(context, R.layout.cell_media_view, R.id.cell_media_view_tv_test, list);
}
public View getView(int position, View convertView, ViewGroup parent)
{
View row = super.getView(position, convertView, parent);
MediaViewHolder holder = (MediaViewHolder) row.getTag();
if (holder == null)
{
holder = new MediaViewHolder(row);
row.setTag(holder);
}
final MediaType mediaType = getMedia(position, this);
String thumbnailPath = mediaType.getThumbnailPath();
String path = mediaType.getPath();
String type = mediaType.getMediaType();
// imageLoader.get(type.equals(Constants.TYPE_IMAGE) ? path :
// thumbnailPath, ImageLoader.getImageListener(holder.ivMedia,
// R.drawable.logo, R.drawable.ic_launcher));
holder.ivType.setVisibility(type.equals(Constants.TYPE_IMAGE) ? View.GONE : View.VISIBLE);
holder.ivMedia.setLayoutParams(new FrameLayout.LayoutParams(THUMBNAIL_SIZE, THUMBNAIL_SIZE));
Picasso.with(getActivity()).load(type.equals(Constants.TYPE_IMAGE) ? path : thumbnailPath).noFade().centerCrop().resize(THUMBNAIL_SIZE, THUMBNAIL_SIZE).placeholder(R.drawable.loading)
.error(R.drawable.no_image).into(holder.ivMedia);
return row;
}
}
public void updateData(ArrayList<MediaType> listMedia, String category)
{
Log.i(TAG, "Updating data for: " + category);
Log.i(TAG, "No of media items: " + listMedia.size());
// this.listMedia.clear();
// this.listMedia.addAll(listMedia);
// mediaAdapter.notifyDataSetChanged();
mediaAdapter = new MediaAdapter(getActivity(), listMedia);
gridView.setAdapter(mediaAdapter);
tvTest.setText(category + ", No of Media : " + listMedia.size());
}
int THUMBNAIL_SIZE = 200;
/**
* @param position
* @return MediaType object from specified position
*/
private MediaType getMedia(int position, MediaAdapter mediaAdapter)
{
return (MediaType) mediaAdapter.getItem(position);
}
}
片段 fragment_media_content.xml ：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/blue"
android:gravity="center"
android:orientation="vertical" >
<TextView
android:id="@+id/fragment_media_content_tv_test"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="@color/white" />
<GridView
android:id="@+id/fragment_media_content_grid_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:horizontalSpacing="5dip"
android:numColumns="3"
android:verticalSpacing="5dip" />
</LinearLayout>
在页面上刷卡（也可以是任何其它事件）我打了一个API，它给了我，我在相应的片段更新一些数据。
On page swipe (or it could be any other event) I hit an API which gives me some data that I have to update in the corresponding Fragment.
每当我从服务器获取数据我称之为 prepareMediaList 方法，该方法调用的了updateData 方法片段。我可以在日志中看到，在列表中的数据，但该数据未在片段显示的的GridView （甚至在的TextView ）。
Whenever I get the data from server I call the prepareMediaList method which calls the updateData method of Fragment. I can see in logs that there is data in list but that data is not shown in the Fragment's GridView (not even in TextView).
我真的没有得到什么是错在于此。
I am really not getting what is wrong in this.
现在已经变得非常沮丧，看起来很简单，但还是没找到任何解决方案。
Now it has become very frustrating, looks so simple but still couldn't find any solution.
修改
我只是想有一个片段只和放大器;它工作正常。因此，有一些东西，是同倍数。
Edit
I just tried with one Fragment only & it is working properly. So there is something which has to do with multiples.
编辑2
我找不到这样做的解决方案，所以我不得不切换到另一种方法。我删除了片段 - 从 ViewPager ，而不是我添加静态的观点吧。在我来说，我添加了四个的GridView s到 ViewPager 。这是简单的＆放大器;有点复杂，但最重要的是，它是工作，我想要的方式。
I couldn't find the solution for this so I had to switch to alternate way. I removed the Fragments from ViewPager instead I added static views to it. In my case I added four GridViews to ViewPager. This was simple & bit complex but most important thing is, it is working the way I wanted.
但我依然在寻找的答案。
But still I am looking for the answer.
推荐答案
检查更多的细节我看你不需要重新initliaze您MediaAdapter内了updateData 方法。
After checking your code more in details i see you do not require to re-initliaze your MediaAdapter inside updateData method.
您只需需要更新您的了updateData 为
listMedia.clear();
this.listMedia.addAll(listMedia);
mediaAdapter.notifyDatasetChanged();
这将重新加载在GridView中的数据。更改我建议将刷新其被用于渲染的GridView在ArrayList中的数据，然后您通知您mediaAdapter重新加载列表。
This will reload your data in gridview. Change i suggested will refresh the data in your arraylist which is being used for rendering gridview and then you notify your mediaAdapter to reload the list.
