如何从 viewpager 刷新或更新所有片段 android
How to refresh or update all fragment from the viewpager android
我有带 tablayout 的 viewpager,里面有 3 个片段。在我的片段 2 和 3 中,我滑动刷新以更新来自 firebase 数据库的数据。
我希望使用工具栏中的 1 个按钮刷新它,并刷新其中的所有片段。
1 还有一个问题是,我必须刷新 2 次片段才能更新 recyclerview.....
不知道怎么办,求助
TwoFragment
public static final String TAG = "TWO_FRAGMENT";
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser) {
} else {
mAuth = FirebaseAuth.getInstance();
userRef = FirebaseDatabase.getInstance().getReference("user_course");
users = FirebaseAuth.getInstance().getCurrentUser();
daftarTugasRef = FirebaseDatabase.getInstance().getReference("tugas");
mTugasRef = FirebaseDatabase.getInstance().getReference("tugas_course");
mFlagTugas = FirebaseDatabase.getInstance().getReference("flag_tugas");
LoadData();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
v = inflater.inflate(R.layout.fragment_two, container, false);
swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
new Handler().postDelayed(new Runnable() {
@Override public void run() {
LoadData();
swipeLayout.setRefreshing(false);
listTugas.clear();
}
private void onLoaded() {
swipeLayout.setEnabled(true);
swipeLayout.setRefreshing(false);
}
}, 500);
}
});
MainActivity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
viewPager = (ViewPager) findViewById(R.id.viewpager);
viewPager.setOffscreenPageLimit(3);
setupViewPager(viewPager);
viewPager.setCurrentItem(position);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
reloadFragment("TWO_FRAGMENT");
setupTabIcons();
}
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new OneFragment(), "ONE");
adapter.addFrag(new TwoFragment(), "TWO");
adapter.addFrag(new ThreeFragment(), "THREE");
viewPager.setAdapter(adapter);
viewPager.getAdapter().notifyDataSetChanged();
}
class ViewPagerAdapter extends FragmentStatePagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public int getItemPosition(@NonNull Object object) {
return POSITION_NONE;
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
// viewPager.getAdapter().notifyDataSetChanged();
// adapter.notifyDataSetChanged();
}
@Override
public void onPageScrollStateChanged(int state) {
}
protected void reloadFragment(String TAG){
// Reload current fragment
Fragment frg = null;
frg = this.getSupportFragmentManager().findFragmentByTag(TAG);
FragmentTransaction ft =this.getSupportFragmentManager().beginTransaction();
ft.detach(frg);
ft.attach(frg);
ft.commit();
}
只需在单击按钮时调用以下方法即可刷新片段 -
protected void reloadFragment(String TAG){
// Reload current fragment
Fragment frg = null;
frg = getActivity().getSupportFragmentManager().findFragmentByTag(TAG);
FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
ft.detach(frg);
ft.attach(frg);
ft.commit();
}
通过以下代码行在 Fragment 中声明您的 TAG 变量 -
public static final String TAG = "HOME_FRAGMENT";
并且每当您在 activity 中推送片段时,请像这样使用相同的标签 -
getSupportFragmentManager().beginTransaction().setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out, android.R.anim.fade_in, android.R.anim.fade_out).replace(container, fragment, tag).commit();
您只需要为每个片段设置一个 TAG。希望您能使用它获得解决方案。
您可以使用 EventBus,将其放入所有片段中:
@Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
@Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this);
}
@Subscribe(threadMode = ThreadMode.MAIN)
public void onEvent(ViewEvent viewEvent) {
if (viewEvent.getMessage().equals("updateViews")) {
updateView();
}
}
当你想更新时,你可以发送这样的事件:
EventBus.getDefault().post(new ViewEvent("updateViews"));
PS: ViewEvent 是一个对象,您必须创建该对象并发送给所有订阅的片段。
public class ViewEvent {
private String message;
public ViewEvent( String message) {
this.message = message;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
我有带 tablayout 的 viewpager,里面有 3 个片段。在我的片段 2 和 3 中,我滑动刷新以更新来自 firebase 数据库的数据。
我希望使用工具栏中的 1 个按钮刷新它,并刷新其中的所有片段。
1 还有一个问题是,我必须刷新 2 次片段才能更新 recyclerview..... 不知道怎么办,求助
TwoFragment
public static final String TAG = "TWO_FRAGMENT";
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser) {
} else {
mAuth = FirebaseAuth.getInstance();
userRef = FirebaseDatabase.getInstance().getReference("user_course");
users = FirebaseAuth.getInstance().getCurrentUser();
daftarTugasRef = FirebaseDatabase.getInstance().getReference("tugas");
mTugasRef = FirebaseDatabase.getInstance().getReference("tugas_course");
mFlagTugas = FirebaseDatabase.getInstance().getReference("flag_tugas");
LoadData();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
v = inflater.inflate(R.layout.fragment_two, container, false);
swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
new Handler().postDelayed(new Runnable() {
@Override public void run() {
LoadData();
swipeLayout.setRefreshing(false);
listTugas.clear();
}
private void onLoaded() {
swipeLayout.setEnabled(true);
swipeLayout.setRefreshing(false);
}
}, 500);
}
});
MainActivity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
viewPager = (ViewPager) findViewById(R.id.viewpager);
viewPager.setOffscreenPageLimit(3);
setupViewPager(viewPager);
viewPager.setCurrentItem(position);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
reloadFragment("TWO_FRAGMENT");
setupTabIcons();
}
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new OneFragment(), "ONE");
adapter.addFrag(new TwoFragment(), "TWO");
adapter.addFrag(new ThreeFragment(), "THREE");
viewPager.setAdapter(adapter);
viewPager.getAdapter().notifyDataSetChanged();
}
class ViewPagerAdapter extends FragmentStatePagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public int getItemPosition(@NonNull Object object) {
return POSITION_NONE;
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
// viewPager.getAdapter().notifyDataSetChanged();
// adapter.notifyDataSetChanged();
}
@Override
public void onPageScrollStateChanged(int state) {
}
protected void reloadFragment(String TAG){
// Reload current fragment
Fragment frg = null;
frg = this.getSupportFragmentManager().findFragmentByTag(TAG);
FragmentTransaction ft =this.getSupportFragmentManager().beginTransaction();
ft.detach(frg);
ft.attach(frg);
ft.commit();
}
只需在单击按钮时调用以下方法即可刷新片段 -
protected void reloadFragment(String TAG){
// Reload current fragment
Fragment frg = null;
frg = getActivity().getSupportFragmentManager().findFragmentByTag(TAG);
FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
ft.detach(frg);
ft.attach(frg);
ft.commit();
}
通过以下代码行在 Fragment 中声明您的 TAG 变量 -
public static final String TAG = "HOME_FRAGMENT";
并且每当您在 activity 中推送片段时,请像这样使用相同的标签 -
getSupportFragmentManager().beginTransaction().setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out, android.R.anim.fade_in, android.R.anim.fade_out).replace(container, fragment, tag).commit();
您只需要为每个片段设置一个 TAG。希望您能使用它获得解决方案。
您可以使用 EventBus,将其放入所有片段中:
@Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
@Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this);
}
@Subscribe(threadMode = ThreadMode.MAIN)
public void onEvent(ViewEvent viewEvent) {
if (viewEvent.getMessage().equals("updateViews")) {
updateView();
}
}
当你想更新时,你可以发送这样的事件:
EventBus.getDefault().post(new ViewEvent("updateViews"));
PS: ViewEvent 是一个对象,您必须创建该对象并发送给所有订阅的片段。
public class ViewEvent {
private String message;
public ViewEvent( String message) {
this.message = message;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}