问题描述
所以我在一个带有tablayout和viewpager的活动中放置了一个searchview。在viewpager中,每个选项卡都有一个带有textview的片段。我试图做的是从searchview获取输入并设置文本带有输入的textview,我似乎无法做到这一点。我试图将来自searchview的输入放在一个包中(这在活动中完成),然后在onCreateView()中获取片段中的参数但是问题在于活动和片段是同时创建的,这意味着搜索视图的输入将为空。
这是活动:
public class SearchActivity extends AppCompatActivity {
TabLayout tabLayout;
ViewPager viewPager;
ViewPagerAdapter viewPagerAdapter;
SearchView searchView;
Toolbar toolbar;
ImageButton imageButtonBack;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search);
bindUI();
viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
viewPagerAdapter.AddFragment(new NewestFragment(),"Newest");
viewPagerAdapter.AddFragment(new OldestFragment(),"Oldest");
viewPager.setAdapter(viewPagerAdapter);
tabLayout.setupWithViewPager(viewPager);
setSearchView();
setimageButtonBack();
}
private void setSearchView() {
searchView.requestFocus();
View v = searchView.findViewById(R.id.search_plate);
v.setBackgroundColor(Color.parseColor("#ffffff"));
searchView.setonQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
Bundle bundle = new Bundle();
bundle.putString("searchViewText",searchView.getQuery().toString());
NewestFragment newestFragment = new NewestFragment();
OldestFragment oldestFragment = new OldestFragment();
newestFragment.setArguments(bundle);
oldestFragment.setArguments(bundle);
searchView.clearFocus();
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
Bundle bundle = new Bundle();
bundle.putString("searchViewText",searchView.getQuery().toString());
NewestFragment newestFragment = new NewestFragment();
OldestFragment oldestFragment = new OldestFragment();
newestFragment.setArguments(bundle);
oldestFragment.setArguments(bundle);
return false;
}
});
}
private void bindUI() {
imageButtonBack = findViewById(R.id.back);
tabLayout = findViewById(R.id.tabs);
viewPager = findViewById(R.id.view_pager);
searchView = findViewById(R.id.search_view_searchactivity);
toolbar = findViewById(R.id.toolbar_selected_category);
}
private void setimageButtonBack() {
imageButtonBack.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
finish();
}
});
}
}
ViewPager的适配器:
public class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> titlesList = new ArrayList<>();
public ViewPagerAdapter(@NonNull FragmentManager fragmentManager) {
super(fragmentManager);
}
@NonNull
@Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
@Override
public int getCount() {
return titlesList.size();
}
@Nullable
@Override
public CharSequence getPageTitle(int position) {
return titlesList.get(position);
}
public void AddFragment(Fragment fragment,String title) {
fragmentList.add(fragment);
titlesList.add(title);
}
@Override
public void notifyDataSetChanged() {
super.notifyDataSetChanged();
}
}
这是片段:
public class NewestFragment extends Fragment {
View view;
TextView textView;
public NewestFragment(){
}
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater,@Nullable ViewGroup container,@Nullable Bundle savedInstanceState) {
view=inflater.inflate(R.layout.fragment_search_newest,container,false);
textView=view.findViewById(R.id.tttttttttttttttttttt);
try {
String searchViewText=getArguments().getString("searchViewText");
textView.setText(searchViewText);
}
catch (Exception e){
//something
}
return view;
}
}
解决方法
片段附加到活动上,因此创建第一个活动就可以了,但是我认为您应该使用MVVM模式并创建viewmodel,然后您可以观察搜索视图并使用该viewmodel类更新片段textview
https://codelabs.developers.google.com/codelabs/kotlin-android-training-live-data/index.html#0
,要更改由 FragmentPagerAdapter 创建的片段,您应该使用 DynamicFragmentPagerAdapter。参考下面的代码。
public class DynamicFragmentPagerAdapter extends PagerAdapter {
private static final String TAG = "DynamicFragmentPagerAdapter";
private final FragmentManager fragmentManager;
public static abstract class FragmentIdentifier implements Parcelable {
private final String fragmentTag;
private final Bundle args;
public FragmentIdentifier(@NonNull String fragmentTag,@Nullable Bundle args) {
this.fragmentTag = fragmentTag;
this.args = args;
}
protected FragmentIdentifier(Parcel in) {
fragmentTag = in.readString();
args = in.readBundle(getClass().getClassLoader());
}
@Override
public void writeToParcel(Parcel dest,int flags) {
dest.writeString(fragmentTag);
dest.writeBundle(args);
}
protected final Fragment newFragment() {
Fragment fragment = createFragment();
Bundle oldArgs = fragment.getArguments();
Bundle newArgs = new Bundle();
if(oldArgs != null) {
newArgs.putAll(oldArgs);
}
if(args != null) {
newArgs.putAll(args);
}
fragment.setArguments(newArgs);
return fragment;
}
protected abstract Fragment createFragment();
}
private ArrayList<FragmentIdentifier> fragmentIdentifiers = new ArrayList<>();
private FragmentTransaction currentTransaction = null;
private Fragment currentPrimaryItem = null;
public DynamicFragmentPagerAdapter(FragmentManager fragmentManager) {
this.fragmentManager = fragmentManager;
}
private int findIndexIfAdded(FragmentIdentifier fragmentIdentifier) {
for (int i = 0,size = fragmentIdentifiers.size(); i < size; i++) {
FragmentIdentifier identifier = fragmentIdentifiers.get(i);
if (identifier.fragmentTag.equals(fragmentIdentifier.fragmentTag)) {
return i;
}
}
return -1;
}
public void addFragment(FragmentIdentifier fragmentIdentifier) {
if (findIndexIfAdded(fragmentIdentifier) < 0) {
fragmentIdentifiers.add(fragmentIdentifier);
notifyDataSetChanged();
}
}
public void removeFragment(FragmentIdentifier fragmentIdentifier) {
int index = findIndexIfAdded(fragmentIdentifier);
if (index >= 0) {
fragmentIdentifiers.remove(index);
notifyDataSetChanged();
}
}
@Override
public int getCount() {
return fragmentIdentifiers.size();
}
@Override
public void startUpdate(@NonNull ViewGroup container) {
if (container.getId() == View.NO_ID) {
throw new IllegalStateException("ViewPager with adapter " + this
+ " requires a view id");
}
}
@SuppressWarnings("ReferenceEquality")
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container,int position) {
if (currentTransaction == null) {
currentTransaction = fragmentManager.beginTransaction();
}
final FragmentIdentifier fragmentIdentifier = fragmentIdentifiers.get(position);
// Do we already have this fragment?
final String name = fragmentIdentifier.fragmentTag;
Fragment fragment = fragmentManager.findFragmentByTag(name);
if (fragment != null) {
currentTransaction.attach(fragment);
} else {
fragment = fragmentIdentifier.newFragment();
currentTransaction.add(container.getId(),fragment,fragmentIdentifier.fragmentTag);
}
if (fragment != currentPrimaryItem) {
fragment.setMenuVisibility(false);
fragment.setUserVisibleHint(false);
}
return fragment;
}
@Override
public void destroyItem(@NonNull ViewGroup container,int position,@NonNull Object object) {
if (currentTransaction == null) {
currentTransaction = fragmentManager.beginTransaction();
}
currentTransaction.detach((Fragment) object);
}
@SuppressWarnings("ReferenceEquality")
@Override
public void setPrimaryItem(@NonNull ViewGroup container,@NonNull Object object) {
Fragment fragment = (Fragment) object;
if (fragment != currentPrimaryItem) {
if (currentPrimaryItem != null) {
currentPrimaryItem.setMenuVisibility(false);
currentPrimaryItem.setUserVisibleHint(false);
}
fragment.setMenuVisibility(true);
fragment.setUserVisibleHint(true);
currentPrimaryItem = fragment;
}
}
@Override
public void finishUpdate(@NonNull ViewGroup container) {
if (currentTransaction != null) {
currentTransaction.commitNowAllowingStateLoss();
currentTransaction = null;
}
}
@Override
public boolean isViewFromObject(@NonNull View view,@NonNull Object object) {
return ((Fragment) object).getView() == view;
}
@Override
public Parcelable saveState() {
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("fragmentIdentifiers",fragmentIdentifiers);
return bundle;
}
@Override
public void restoreState(Parcelable state,ClassLoader loader) {
Bundle bundle = ((Bundle)state);
bundle.setClassLoader(loader);
fragmentIdentifiers = bundle.getParcelableArrayList("fragmentIdentifiers");
}
}