我试图在 ViewPager 中包含的片段中调用 getActivity() 的活动，并且该 ViewPager 包含在 Fragment 中。我需要在这些片段中调用此活动的一些方法，但 getActivity 始终为此片段返回 NULL。
我不知道这是否是一个好方法，但我需要视图寻呼机包含的片段根据操作栏操作更新其内容并显示已完成或有错误的消息。
对此提供帮助将不胜感激。
这是代码：
内部片段：
public class ReportSessionsFragment extends ReportPageFragment implements IUpdateView {
private static final String TAG = ReportSessionsFragment.class.getSimpleName();
private Sessions fSessions;
private List<Report> reportList = null;
private ReportsAdapter adapter = null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return super.onCreateView(inflater, container, savedInstanceState);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
settings = ((BaseActivity)getActivity()).settings;
}
@Override
public void onStart() {
super.onStart();
setCounter(db.getSessionsCount());
if(settings.getSelectedRoom() != null){
reportList = db.getSessionsByRoom(settings.getSelectedRoom().getName(),
settings.getStatusSelectedList());
adapter = new ReportsAdapter(getActivity(), reportList, EReport.Sessions);
mRecyclerView.setAdapter(adapter);
}
}
@Override
public void onStop() {
super.onStop();
}
@Override
public void reload() {
HashMap<String, Object> parameters = new HashMap<>();
parameters.put(Fetcher.REQUEST_PARAMETERS, getEventInformation());
showProgress(getString(R.string.txt_requesting_sessions));
fSessions = new Sessions(getActivity(), this);
fSessions.handleSession(parameters, false);
}
@Override
public void delta() {
}
@Override
public void updateProcess(String message) {
}
@Override
public void onProcessEnded(RequestType type, boolean isProvisioningCompleted, String message) {
reportList = db.getSessionsByRoom(settings.getSelectedRoom().getName(),
settings.getStatusSelectedList());
adapter.notifyDataSetChanged();
hideProgress();
}
@Override
public void onError(Exception e, boolean isProvisioningCompleted) {
hideProgress();
showError(getString(R.string.txt_error_title),
e.getMessage());
}
}
包含 ViewPager 的片段：
public class ReportSessionsFragment extends ReportPageFragment implements IUpdateView {
private static final String TAG = ReportSessionsFragment.class.getSimpleName();
private Sessions fSessions;
private List<Report> reportList = null;
private ReportsAdapter adapter = null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return super.onCreateView(inflater, container, savedInstanceState);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
settings = ((BaseActivity)getActivity()).settings;
}
@Override
public void onStart() {
super.onStart();
setCounter(db.getSessionsCount());
if(settings.getSelectedRoom() != null){
reportList = db.getSessionsByRoom(settings.getSelectedRoom().getName(),
settings.getStatusSelectedList());
adapter = new ReportsAdapter(getActivity(), reportList, EReport.Sessions);
mRecyclerView.setAdapter(adapter);
}
}
@Override
public void onStop() {
super.onStop();
}
@Override
public void reload() {
HashMap<String, Object> parameters = new HashMap<>();
parameters.put(Fetcher.REQUEST_PARAMETERS, getEventInformation());
showProgress(getString(R.string.txt_requesting_sessions));
fSessions = new Sessions(getActivity(), this);
fSessions.handleSession(parameters, false);
}
@Override
public void delta() {
}
@Override
public void updateProcess(String message) {
}
@Override
public void onProcessEnded(RequestType type, boolean isProvisioningCompleted, String message) {
reportList = db.getSessionsByRoom(settings.getSelectedRoom().getName(),
settings.getStatusSelectedList());
adapter.notifyDataSetChanged();
hideProgress();
}
@Override
public void onError(Exception e, boolean isProvisioningCompleted) {
hideProgress();
showError(getString(R.string.txt_error_title),
e.getMessage());
}
}
活动：
public class ReportsActivity extends BaseActivity implements IReports {
private static final String TAG = ReportsActivity.class.getSimpleName();
private ReportsFragment reportFragment;
private HashMap<Integer, MenuItem> menuReports;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
reportFragment = new ReportsFragment();
addFragment(reportFragment);
}
@Override
protected void onStart() {
super.onStart();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_reports, menu);
menuReports = new HashMap<>();
for(int index = 0; index < menu.size(); index++ ){
MenuItem mi = menu.getItem(index);
menuReports.put(mi.getItemId(), mi);
}
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
ReportPageFragment reportPage = (ReportPageFragment)reportFragment.getCurrentReportPage();
switch (item.getItemId()){
case R.id.action_reload:
reportPage.reload();
break;
case R.id.action_delta:
reportPage.delta();
break;
}
return true;
}
@Override
public void displayOptionsByReport(int position) {
MenuItem miReload = null;
if(menuReports != null){
miReload = (MenuItem) menuReports.get(R.id.action_reload);
}
switch (position){
case REPORT_SESSION:
miReload.setVisible(true);
break;
case REPORT_ENROLLMENT:
miReload.setVisible(true);
break;
case REPORT_REGISTRANTS:
miReload.setVisible(false);
break;
case REPORT_ASSOCIATIONS:
miReload.setVisible(false);
break;
}
}
}
FragmentPagerAdapter：
public class ReportsPagerAdapter extends FragmentStatePagerAdapter {
private Context ctx;
public ReportsPagerAdapter(Context ctx, FragmentManager fm) {
super(fm);
this.ctx = ctx;
}
@Override
public Fragment getItem(int position) {
Fragment fragment = null;
switch (position){
case 0:
fragment = Fragment.instantiate(ctx, ReportSessionsFragment.class.getName());
break;
case 1:
fragment = Fragment.instantiate(ctx, ReportEnrollmentFragment.class.getName());
break;
case 2:
fragment = Fragment.instantiate(ctx, ReportRegistrantsFragment.class.getName());
break;
case 3:
fragment = Fragment.instantiate(ctx, ReportAssociationsFragment.class.getName());
break;
}
return fragment;
}
@Override
public int getCount() {
String[] reportListNames = ctx.getResources().getStringArray(R.array.reports);
return reportListNames.length;
}
@Override
public CharSequence getPageTitle(int position) {
String[] reportListNames = ctx.getResources().getStringArray(R.array.reports);
return reportListNames[position];
}
}
