我有一个标签式活动，允许用户为recyclerview中的条目选择复选框 . 当用户在不同选项卡之间滑动时，如果已选中复选框，则复选框不会保留其已检查状态 . 任何帮助将不胜感激 . 这是代码：
public class MyDirectory extends AppCompatActivity {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_directory);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "New Message", Snackbar.LENGTH_LONG)
.setAction("Go", new View.OnClickListener(){
@Override
public void onClick(View view)
{
Intent message = new Intent(MyDirectory.this, newScheduledNotification.class);
startActivity(message);
}
}).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_my_directory, menu);
//SearchView searchView = (SearchView) MenuItemCompat.getActionView(R.id.action_search);
//searchView.setOnQueryTextListener(MyDirectory.this);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
else if (id == R.id.go_home)
{
Intent goHome = new Intent(MyDirectory.this, menuHomepage.class);
startActivity(goHome);
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment
{
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment()
{
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber)
{
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
TextView textView;
RecyclerView recyclerView;
public List<directoryEntry> directoryEntryList = new ArrayList<>();
directoryEntryAdapter dAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
Toast.makeText(getActivity(), "On Create View", Toast.LENGTH_SHORT).show();
String type = "";
Bundle extras = getActivity().getIntent().getExtras();
// Get Bundle Extras
if (extras != null) {
type = extras.getString("directoryAction");
//Toast.makeText(getActivity(), type, Toast.LENGTH_SHORT).show();
}
View rootView = inflater.inflate(R.layout.fragment_my_directory, container, false);
textView = (TextView) rootView.findViewById(R.id.section_label);
recyclerView = (RecyclerView) rootView.findViewById(R.id.directory_recycler_view);
dAdapter = new directoryEntryAdapter(directoryEntryList);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), LinearLayoutManager.VERTICAL));
recyclerView.setAdapter(dAdapter);
if (type.equals("Send Instruction"))
{
//Toast.makeText(getActivity(), "IN IF STATEMENT", Toast.LENGTH_SHORT).show();
TextView instructionText = (TextView) rootView.findViewById(R.id.InstructionField);
instructionText.setText("Choose All Recipients");
}
if (getArguments().getInt(ARG_SECTION_NUMBER) == 1)
{
prepareParentData(rootView);
textView.setText(getString(R.string.section_format) + " Parent Directory");
return rootView;
}
else if (getArguments().getInt(ARG_SECTION_NUMBER) == 2)
{
prepareTeacherData(rootView);
textView.setText(getString(R.string.section_format) + " Staff Directory");
return rootView;
}
else if (getArguments().getInt(ARG_SECTION_NUMBER) == 3)
{
prepareStudentData(rootView);
textView.setText(getString(R.string.section_format) + " Student Directory");
return rootView;
}
else
return rootView;
}
public void prepareParentData(View rootview)
{
String method = "parent_directory";
if(getActivity() == null)
{
Toast.makeText(getActivity().getApplicationContext(), "NULL", Toast.LENGTH_LONG).show();
}
else if (getActivity() != null)
{
DirectoryBackgroundTask directoryBackgroundTask = new DirectoryBackgroundTask(getActivity(), rootview);
directoryBackgroundTask.execute(method);
}
}
public void prepareTeacherData(View rootView)
{
String method = "faculty_directory";
DirectoryBackgroundTask directoryBackgroundTask = new DirectoryBackgroundTask(getActivity(), rootView);
directoryBackgroundTask.execute(method);
}
public void prepareStudentData(View rootView)
{
String method = "student_directory";
DirectoryBackgroundTask directoryBackgroundTask = new DirectoryBackgroundTask(getActivity(), rootView);
directoryBackgroundTask.execute(method);
}
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "Parent Directory";
case 1:
return "Staff Directory";
case 2:
return "Student Directory";
}
return null;
}
}
}