Java 如何修复Android中片段中未找到的视图
在我的应用程序中，我想从服务器获取一些数据，并将其显示到Java 如何修复Android中片段中未找到的视图,java,android,android-fragments,Java,Android,Android Fragments,在我的应用程序中，我想从服务器获取一些数据，并将其显示到RecyclerView中，为此，我应该使用Fragment 我希望当用户看到片段时调用我的API调用方法。但当使用下面的代码时，显示强制关闭错误 代码： @Override public void setUserVisibleHint(boolean isVisibleToUser) { super.setUserVisibleHint(isVisibleToUser); if (isVisibleToUser){
RecyclerViewFragment我希望当用户看到
片段时@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser){
getData(getActivity());
}
}
public class NotificationAllFrag extends Fragment {
@BindView(R.id.mainNotification_recyclerView)
RecyclerView mainNotification_recyclerView;
@BindView(R.id.mainNotification_noNotificationTxt)
TextView mainNotification_noNotificationTxt;
@BindView(R.id.mainNotification_progressBar)
ProgressBar mainNotification_progressBar;
@BindView(R.id.newsPageLoadLay)
RelativeLayout newsPageLoadLay;
private Context context;
private List<Datum> model = new ArrayList<>();
public static NotificationListAdapter notificationListAdapter;
private SharedPrefrencesHandler prefrencesHandler;
private String token = "";
private LinearLayoutManager layoutManager;
public NotificationAllFrag() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_notification_all, container, false);
//Initialize
ButterKnife.bind(this, view);
context = getActivity();
notificationListAdapter = new NotificationListAdapter(context, model);
prefrencesHandler = new SharedPrefrencesHandler(context);
layoutManager = new LinearLayoutManager(context);
//RecyclerView
mainNotification_recyclerView.setLayoutManager(layoutManager);
mainNotification_recyclerView.setHasFixedSize(true);
//Get token
token = prefrencesHandler.getFromShared(SharedPrefrencesKeys.TOKEN.name());
// Lazy loader
newsPageLoadLay.setVisibility(View.GONE);
mainNotification_recyclerView.setOnScrollListener(new EndlessRecyclerLinearPage1(layoutManager) {
@Override
public void onLoadMore(int current_page) {
ExploreSendData sendData = new ExploreSendData();
sendData.setPageIndex(current_page);
sendData.setPageSize(10);
sendData.setShowFollows(true);
sendData.setShowMovies(false);
sendData.setShowNews(false);
sendData.setShowReplies(true);
sendData.setShowSeries(false);
sendData.setShowSuggestions(true);
newsPageLoadLay.setVisibility(View.VISIBLE);
InterfaceApi api = ApiClient.getClient().create(InterfaceApi.class);
Call<ExploreResponse> call = api.getExplore(token, sendData);
call.enqueue(new Callback<ExploreResponse>() {
@Override
public void onResponse(Call<ExploreResponse> call, Response<ExploreResponse> response) {
if (response.body().getData() != null && response.body().getStatusCode() != 401
&& response.body().getStatusCode() != 402) {
if (response.body().getData().size() > 0) {
notificationListAdapter.addNewItem(response.body().getData());
//Gone no explore
newsPageLoadLay.setVisibility(View.GONE);
}
} else {
prefrencesHandler.remove(SharedPrefrencesKeys.TOKEN.name());
startActivity(new Intent(context, LoginActivity.class));
}
newsPageLoadLay.setVisibility(View.GONE);
}
@Override
public void onFailure(Call<ExploreResponse> call, Throwable t) {
newsPageLoadLay.setVisibility(View.GONE);
}
});
}
});
getData(getActivity());
return view;
}
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser){
getData(getActivity());
}
}
public void getData(final Context context) {
ExploreSendData sendData = new ExploreSendData();
sendData.setPageIndex(1);
sendData.setPageSize(10);
sendData.setShowFollows(true);
sendData.setShowMovies(false);
sendData.setShowNews(false);
sendData.setShowReplies(true);
sendData.setShowSeries(false);
sendData.setShowSuggestions(true);
mainNotification_progressBar.setVisibility(View.VISIBLE);
InterfaceApi api = ApiClient.getClient().create(InterfaceApi.class);
Call<ExploreResponse> call = api.getExplore(
new SharedPrefrencesHandler(context).getFromShared(SharedPrefrencesKeys.TOKEN.name()), sendData);
call.enqueue(new Callback<ExploreResponse>() {
@Override
public void onResponse(Call<ExploreResponse> call, Response<ExploreResponse> response) {
if (response.body().getData() != null && response.body().getStatusCode() != 401
&& response.body().getStatusCode() != 402) {
if (response.body().getData().size() > 0) {
model.clear();
model.addAll(response.body().getData());
notificationListAdapter.notifyDataSetChanged();
mainNotification_recyclerView.setAdapter(notificationListAdapter);
//Gone no explore
mainNotification_noNotificationTxt.setVisibility(View.GONE);
} else {
mainNotification_noNotificationTxt.setVisibility(View.VISIBLE);
mainNotification_recyclerView.setVisibility(View.GONE);
}
} else {
prefrencesHandler.remove(SharedPrefrencesKeys.TOKEN.name());
startActivity(new Intent(context, LoginActivity.class));
}
mainNotification_progressBar.setVisibility(View.GONE);
}
@Override
public void onFailure(Call<ExploreResponse> call, Throwable t) {
mainNotification_progressBar.setVisibility(View.GONE);
}
});
}
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ProgressBar.setVisibility(int)' on a null object reference
at com.app.test.Fragments.MainNotificationFrags.NotificationAllFrag.getData(NotificationAllFrag.java:157)
at com.app.test.Fragments.MainNotificationFrags.NotificationAllFrag.setUserVisibleHint(NotificationAllFrag.java:142)
at android.support.v4.app.FragmentStatePagerAdapter.setPrimaryItem(FragmentStatePagerAdapter.java:157)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1266)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1116)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1642)
at android.view.View.measure(View.java:17496)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
at android.view.View.measure(View.java:17496)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1658)
at android.view.View.measure(View.java:17496)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
at android.view.View.measure(View.java:17496)
at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1081)
at android.view.View.measure(View.java:17496)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5466)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:17496)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5466)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1438)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:724)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:615)
at android.view.View.measure(View.java:17496)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5466)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at android.view.View.measure(View.java:17496)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5466)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1438)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:724)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:615)
at android.view.View.measure(View.java:17496)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5466)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2636)
at android.view.View.measure(View.java:17496)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2031)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1193)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1400)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1078)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5875)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5349)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser){
getData(getActivity());
}
}
public class NotificationAllFrag extends Fragment {
@BindView(R.id.mainNotification_recyclerView)
RecyclerView mainNotification_recyclerView;
@BindView(R.id.mainNotification_noNotificationTxt)
TextView mainNotification_noNotificationTxt;
@BindView(R.id.mainNotification_progressBar)
ProgressBar mainNotification_progressBar;
@BindView(R.id.newsPageLoadLay)
RelativeLayout newsPageLoadLay;
private Context context;
private List<Datum> model = new ArrayList<>();
public static NotificationListAdapter notificationListAdapter;
private SharedPrefrencesHandler prefrencesHandler;
private String token = "";
private LinearLayoutManager layoutManager;
public NotificationAllFrag() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_notification_all, container, false);
//Initialize
ButterKnife.bind(this, view);
context = getActivity();
notificationListAdapter = new NotificationListAdapter(context, model);
prefrencesHandler = new SharedPrefrencesHandler(context);
layoutManager = new LinearLayoutManager(context);
//RecyclerView
mainNotification_recyclerView.setLayoutManager(layoutManager);
mainNotification_recyclerView.setHasFixedSize(true);
//Get token
token = prefrencesHandler.getFromShared(SharedPrefrencesKeys.TOKEN.name());
// Lazy loader
newsPageLoadLay.setVisibility(View.GONE);
mainNotification_recyclerView.setOnScrollListener(new EndlessRecyclerLinearPage1(layoutManager) {
@Override
public void onLoadMore(int current_page) {
ExploreSendData sendData = new ExploreSendData();
sendData.setPageIndex(current_page);
sendData.setPageSize(10);
sendData.setShowFollows(true);
sendData.setShowMovies(false);
sendData.setShowNews(false);
sendData.setShowReplies(true);
sendData.setShowSeries(false);
sendData.setShowSuggestions(true);
newsPageLoadLay.setVisibility(View.VISIBLE);
InterfaceApi api = ApiClient.getClient().create(InterfaceApi.class);
Call<ExploreResponse> call = api.getExplore(token, sendData);
call.enqueue(new Callback<ExploreResponse>() {
@Override
public void onResponse(Call<ExploreResponse> call, Response<ExploreResponse> response) {
if (response.body().getData() != null && response.body().getStatusCode() != 401
&& response.body().getStatusCode() != 402) {
if (response.body().getData().size() > 0) {
notificationListAdapter.addNewItem(response.body().getData());
//Gone no explore
newsPageLoadLay.setVisibility(View.GONE);
}
} else {
prefrencesHandler.remove(SharedPrefrencesKeys.TOKEN.name());
startActivity(new Intent(context, LoginActivity.class));
}
newsPageLoadLay.setVisibility(View.GONE);
}
@Override
public void onFailure(Call<ExploreResponse> call, Throwable t) {
newsPageLoadLay.setVisibility(View.GONE);
}
});
}
});
getData(getActivity());
return view;
}
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser){
getData(getActivity());
}
}
public void getData(final Context context) {
ExploreSendData sendData = new ExploreSendData();
sendData.setPageIndex(1);
sendData.setPageSize(10);
sendData.setShowFollows(true);
sendData.setShowMovies(false);
sendData.setShowNews(false);
sendData.setShowReplies(true);
sendData.setShowSeries(false);
sendData.setShowSuggestions(true);
mainNotification_progressBar.setVisibility(View.VISIBLE);
InterfaceApi api = ApiClient.getClient().create(InterfaceApi.class);
Call<ExploreResponse> call = api.getExplore(
new SharedPrefrencesHandler(context).getFromShared(SharedPrefrencesKeys.TOKEN.name()), sendData);
call.enqueue(new Callback<ExploreResponse>() {
@Override
public void onResponse(Call<ExploreResponse> call, Response<ExploreResponse> response) {
if (response.body().getData() != null && response.body().getStatusCode() != 401
&& response.body().getStatusCode() != 402) {
if (response.body().getData().size() > 0) {
model.clear();
model.addAll(response.body().getData());
notificationListAdapter.notifyDataSetChanged();
mainNotification_recyclerView.setAdapter(notificationListAdapter);
//Gone no explore
mainNotification_noNotificationTxt.setVisibility(View.GONE);
} else {
mainNotification_noNotificationTxt.setVisibility(View.VISIBLE);
mainNotification_recyclerView.setVisibility(View.GONE);
}
} else {
prefrencesHandler.remove(SharedPrefrencesKeys.TOKEN.name());
startActivity(new Intent(context, LoginActivity.class));
}
mainNotification_progressBar.setVisibility(View.GONE);
}
@Override
public void onFailure(Call<ExploreResponse> call, Throwable t) {
mainNotification_progressBar.setVisibility(View.GONE);
}
});
}
公共类NotificationAllFrag扩展片段{
@BindView（R.id.mainNotification\U recyclerView）
RecyclerView主通知\u RecyclerView；
@BindView（R.id.mainNotification\u noNotificationTxt）
TextView main notification_notificationtxt；
@BindView（R.id.main通知\u进度条）
ProgressBar主通知_ProgressBar；
@BindView（R.id.newsPageLoadLay）
相对Yout newsPageLoadLay；
私人语境；
私有列表模型=新的ArrayList（）；
公共静态NotificationListAdapter NotificationListAdapter；
私人股优先股；
私有字符串令牌=”；
私人专线经理；布局经理；
公共通知ALLFRAG（）{
//必需的空公共构造函数
}
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
//为该碎片膨胀布局
视图=充气机。充气（R.layout.fragment\u notification\u all，container，false）；
//初始化
ButterKnife.bind（这个，视图）；
context=getActivity（）；
notificationListAdapter=新notificationListAdapter（上下文、模型）；
prefrencesHandler=新共享的prefrencesHandler（上下文）；
layoutManager=新的LinearLayoutManager（上下文）；
//回收视图
main通知\u recyclerView.setLayoutManager（layoutManager）；
main通知_recyclerView.setHasFixedSize（true）；
//领取代币
token=PrefrenceHandler.getFromShared（SharedReferencesKeys.token.name（））；
//惰性装载机
newsPageLoadLay.setVisibility（View.GONE）；
mainNotification_recyclerView.setOnScrollListener（新的EndlesRecyclerLineArpage1（layoutManager）{
@凌驾
public void onLoadMore（int当前页面）{
ExploreSendData sendData=新建ExploreSendData（）；
sendData.setPageIndex（当前页面）；
sendData.setPageSize（10）；
sendData.setShowFollows（真）；
sendData.setShowMovies（假）；
sendData.setShowNews（假）；
sendData.setShowReplies（true）；
sendData.setShowSeries（假）；
sendData.setShowSuggestions（true）；
newsPageLoadLay.setVisibility（View.VISIBLE）；
InterfaceApi api=ApiClient.getClient（）.create（InterfaceApi.class）；
Call Call=api.getExplore（令牌，sendData）；
call.enqueue（新回调（）{
@凌驾
公共void onResponse（调用、响应）{
if（response.body（）.getData（）！=null&&response.body（）.getStatusCode（）！=401
&&response.body（）.getStatusCode（）！=402）{
if（response.body（）.getData（）.size（）>0）{
notificationListAdapter.addNewItem（response.body（）.getData（））；
//不去探索
newsPageLoadLay.setVisibility（View.GONE）；
}
}否则{
删除（sharedpreferenceskeys.TOKEN.name（））；
startActivity（新意图（上下文、LoginActivity.class））；
}
newsPageLoadLay.setVisibility（View.GONE）；
}
@凌驾
失败时公共无效（调用调用，可丢弃的t）{
newsPageLoadLay.setVisibility（View.GONE）；
}
});
}
});
getData（getActivity（））；
返回视图；
}
@凌驾
public void setUserVisibleHint（布尔值isVisibleToUser）{
super.setUserVisibleHint（isVisibleToUser）；
如果（isVisibleToUser）{
getData（getActivity（））；
}
}
公共void getData（最终上下文）{
ExploreSendData sendData=新建ExploreSendData（）；
sendData.setPageIndex（1）；
sendData.setPageSize（10）；
sendData.setShowFollows（真）；
sendData.setShowMovies（假）；
sendData.setShowNews（假）；
sendData.setShowReplies（true）；
sendData.setShowSeries（假）；
sendData.setShowSuggestions（true）；
main通知_progressBar.setVisibility（View.VISIBLE）；
InterfaceApi api=ApiClient.getClient（）.create（InterfaceApi.class）；
Call=api.getExplore(
新的SharedReferencesHandler（context.getFromShared（SharedReferenceskeys.TOKEN.name（）），sendData）；
call.enqueue（新回调（）{
@凌驾
公共void onResponse（调用、响应）{
if（response.body（）.getData（）！=null&&response.body（）.getStatusCode（）！=401
&&response.body（）.getStatusCode（）！=402）{
if（response.body（）.getData（）.size（）>0）{
model.clear（）；
model.addAll（response.body（）.getData（））；
notificationListAdapter.notifyDataSetChanged（）；
mainNotification_recyclerView.setAdapter（notificationListAdapter）；
//不去探索
main notification_nonnotificationtxt.setVisibility（View.GONE）；
}否则{
mainNotification_noNotificationTxt.setVisibility
private boolean isVisible = false;
private View view;
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser) {
isVisible = true;
onVisible();
}
}
// onVisible method
private void onVisible() {
// edited here
if (isVisible && view != null && mainNotification_progressBar != null) {
getData(getActivity());
}
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_notification_all, container, false);
// add ButterKnife here
ButterKnife.bind(this, view);
onVisible();
return view;
}