所以我整天都尝试了这个,但没有成功。
我用ViewPager TabLayout连接了两个片段,
,并且我尝试将ProgressBar放在每个片段上,它不会显示。 我还尝试将其放在MainActivity上,该MainActivity初始化两个片段的ViewPager,也不会显示。
我尝试了一个新项目,它显示了。我在做什么错了?
我在代码中的所有位置都删除了ProgressBar,因为它不起作用。如果您能自己看到它,则这里是代码。
第一个片段
public class FilmShow extends Fragment {
private static RecyclerView recyclerView;
private static final String API_KEY = "2e08750083b7e21e96e915011d3f8e2d";
private static final String TAG = FilmShow.class.getSimpleName();
public FilmShow() {
// Required empty public constructor
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getResponse getResponse = new getResponse();
getResponse.execute();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_film_show, container, false);
recyclerView = view.findViewById(R.id.recycler_tv);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(layoutManager);
recyclerView.setVisibility(View.GONE);
return view;
}
private class getResponse extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
ApiInterface apiInterface = ApiClient.getList().create(ApiInterface.class);
Call<Response> responseCall = apiInterface.getFilmList(API_KEY);
responseCall.enqueue(new Callback<Response>() {
@Override
public void onResponse(Call<Response> call, retrofit2.Response<Response> response) {
List<ResultsItem> resultsItemList = response.body().getResults();
recyclerView.setAdapter(new FilmShowRecyclerAdapter(resultsItemList, getContext()));
}
@Override
public void onFailure(Call<Response> call, Throwable t) {
Log.d(TAG, t.toString());
}
});
return null;
}
@Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
}
}
另一个片段
public class TvShow extends Fragment {
private static RecyclerView recyclerView;
private static final String API_KEY = "2e08750083b7e21e96e915011d3f8e2d";
private static final String TAG = TvShow.class.getSimpleName();
public TvShow() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View view = inflater.inflate(R.layout.fragment_tv_show, container, false);
recyclerView = view.findViewById(R.id.recycler_tv);
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
CallInternet callInternet = new CallInternet();
callInternet.execute();
}
});
thread.run();
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(layoutManager);
return view;
}
private class CallInternet extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... voids) {
ApiInterface apiInterface = ApiClient.getList().create(ApiInterface.class);
Call<Response> responseCall = apiInterface.getTvList(API_KEY);
responseCall.enqueue(new Callback<Response>() {
@Override
public void onResponse(Call<Response> call, retrofit2.Response<Response> response) {
List<ResultsItem> resultsTv = response.body().getResults();
recyclerView.setAdapter(new TvShowRecyclerAdapter(resultsTv, getContext()));
}
@Override
public void onFailure(Call<Response> call, Throwable t) {
Log.d(TAG, t.toString());
}
});
return null;
}
@Override
protected void onProgressUpdate(Void... values) {
}
@Override
protected void onPostExecute(Void aVoid) {
recyclerView.setVisibility(View.VISIBLE);
}
}
MainActivity
public class MainActivity extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
private ViewPagerAdapter adapter;
public MainActivity() {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
// placing toolbar in place of action bar
setSupportActionBar(toolbar);
/*Membuat tabLayout*/
tabLayout = findViewById(R.id.tablayout);
viewPager = findViewById(R.id.viewpager);
adapter = new ViewPagerAdapter(getSupportFragmentManager());
//adding fragment
adapter.AddFragment(new TvShow(), "Tv");
adapter.AddFragment(new FilmShow(), "Film");
// Adapter Setrup
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.action_change_settings) {
Intent intent = new Intent(Settings.ACTION_LOCALE_SETTINGS);
startActivity(intent);
}
return super.onOptionsItemSelected(item);
}
}
编辑:
修改了另一个片段,以在onCreateView上显示ProgressBar,它可以工作,但不会停止加载
...............
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View view = inflater.inflate(R.layout.fragment_tv_show, container, false);
recyclerView = view.findViewById(R.id.recycler_tv);
progressBar = view.findViewById(R.id.progress_bar);
...............
XML文件
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:tools="http://schemas.android.com/tools"
android:padding="16dp"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_tv"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="@layout/item_tv"
android:visibility="gone" />
<Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ProgressBar
android:id="@+id/progress_bar"
style="?android:attr/progressBarStyle"
android:textAlignment="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</RelativeLayout>
编辑II:
public class TvShow extends Fragment {
private static RecyclerView recyclerView;
private static final String API_KEY = "2e08750083b7e21e96e915011d3f8e2d";
private static final String TAG = TvShow.class.getSimpleName();
private static ProgressBar progressBar;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
progressBar.findViewById(R.id.progress_bar);
progressBar.setVisibility(VISIBLE);
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
CallInternet callInternet = new CallInternet();
callInternet.execute();
}
});
thread.run();
}
public TvShow() {
// Required empty public constructor
}
java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“ android.view.View android.widget.ProgressBar.findViewById(int)”
答案 0 :(得分:1)
您尝试过这样吗
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View view = inflater.inflate(R.layout.fragment_tv_show, container, false);
recyclerView = view.findViewById(R.id.recycler_tv);
progressBar = view.findViewById(R.id.progress_bar);
// progress bar Shows first
progressBar.setVisibility(VISIBLE);
ApiInterface apiInterface = ApiClient.getList().create(ApiInterface.class);
Call<Response> responseCall = apiInterface.getFilmList(API_KEY);
responseCall.enqueue(new Callback<Response>() {
@Override
public void onResponse(Call<Response> call, retrofit2.Response<Response> response) {
List<ResultsItem> resultsItemList = response.body().getResults();
recyclerView.setAdapter(new FilmShowRecyclerAdapter(resultsItemList, getContext()));
progressBar.setVisibility(GONE);
}
@Override
public void onFailure(Call<Response> call, Throwable t) {
Log.d(TAG, t.toString());
progressBar.setVisibility(GONE);
}
});
此代码不需要Asyntask,我只是将其隐藏并显示