Question

我已经用RecyclerView实现了SearchView，但出现错误。我正在开发android weather app，我想实现功能，当用户启动应用程序时，用户可以在用户点击名称时搜索cityName，它应该显示cityName和天气信息，用户也可以添加城市添加和删除它，但是我已按照SearchView的本教程进行操作searchviewtutorial

但我收到此错误

 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)
                   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.SearchView.setOnQueryTextListener(android.support.v7.widget.SearchView$OnQueryTextListener)' on a null object reference
                      at yodgobekkomilov.edgar.com.weather.MainActivity.onCreate(MainActivity.java:47)

我已关注this link，但没有解决问题。

在我的MainActivity.java文件下面，该文件已使用Recyclerview实现了SearchView

    public class MainActivity extends AppCompatActivity {
        private List<Weather> weatherArrayList;
        private List<ForecastEndingPoint> conditionList;
        private ProgressDialog pDialog;
        private RecyclerView recyclerView;
        private SearchView mSearchView;
        private WeatherAdapter adapter;
        private ConditionAdapter conditionAdapter;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            mSearchView = (SearchView) findViewById(R.id.searchView);
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Loading Data.. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();

            //Creating an object of our api interface

            mSearchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
                @Override
                public boolean onQueryTextSubmit(String query) {
                    ApiService api = WeatherClient.getApiService();

                    /**
                     * Calling JSON
                     */
                    Call<List<Weather>> call = api.getWeather("6bed69052a864d44a8e165653183008", "Andijan");


                    /**
                     * Enqueue Callback will be call when get response...
                     */
                    call.enqueue(new Callback<List<Weather>>() {

                        @Override
                        public void onResponse(Call<List<Weather>> call, Response<List<Weather>> response) {
                            //Dismiss Dialog
                            //    Log.d("url", call.request().url().toString());
                            pDialog.dismiss();

                            if (response.isSuccessful()) {
                                /**
                                 * Got Successfully
                                 */
                                weatherArrayList = response.body();

                                recyclerView = (RecyclerView) findViewById(R.id.recycler_view);

                                LinearLayoutManager eLayoutManager = null;

                                adapter = new WeatherAdapter((List<Weather>) weatherArrayList);
                                eLayoutManager = new LinearLayoutManager(getApplicationContext());
                                recyclerView.setLayoutManager(eLayoutManager);
                                recyclerView.setItemAnimator(new DefaultItemAnimator());
                                recyclerView.setAdapter(adapter);
                            }
                        }


                        @Override
                        public void onFailure(Call<List<Weather>> call, Throwable t) {
                            pDialog.dismiss();
                        }
                    });
                   getApi();

                    return false;
                }

                @Override
                public boolean onQueryTextChange(String newText) {
                    return false;
                }
            });

        }


        public void getApi(){
            ApiService apiService = WeatherClient.getApiService();
            Call<ForecastEndingPoint> conditionCall = apiService.forecast("6bed69052a864d44a8e165653183008", "Andijan", 5);
            conditionCall.enqueue(new Callback<ForecastEndingPoint>() {

                @Override
                public void onResponse(Call<ForecastEndingPoint> conditionCall, Response<ForecastEndingPoint> response) {
                    //Dismiss Dialog
                    //    Log.d("url", call.request().url().toString());
                    if (pDialog != null && pDialog.isShowing()) {
                        pDialog.dismiss();
                    }

                    if (response.isSuccessful()) {
                        /**
                         * Got Successfully
                         */
                        conditionList = Collections.singletonList(response.body());

                        recyclerView = findViewById(R.id.recycler_view);

                        LinearLayoutManager eLayoutManager = null;
                        Context context = getApplicationContext();
                        Context picassoContext = getApplicationContext();
                        conditionAdapter = new ConditionAdapter(conditionList, context, picassoContext);
                        eLayoutManager = new LinearLayoutManager(getApplicationContext());
                        recyclerView.setLayoutManager(eLayoutManager);
                        recyclerView.setItemAnimator(new DefaultItemAnimator());
                        recyclerView.setAdapter(conditionAdapter);

                    }
                }

                @Override
                public void onFailure(Call<ForecastEndingPoint> conditionCall, Throwable t) {
                    pDialog.dismiss();
                }
            });
        }
        }

在我托管了recyclerview的activity_main.xml文件下面。

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/activity_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/recycler_view"
        android:fadeScrollbars="true"
        android:scrollbars="vertical"/>

    </RelativeLayout>

在我已实现Searchview的search.xml下方

<android.support.design.widget.AppBarLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.Toolbar
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.SearchView
            android:id="@+id/searchView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:iconifiedByDefault="false"
            android:queryHint="Search Here"
            android:layout_centerHorizontal="true" />

    </android.support.v7.widget.Toolbar>

</android.support.design.widget.AppBarLayout>

Answer 1

如果在本教程中看到的是“ SearchView”，而不是“ android.support.v7.widget.SearchView”。将其更改为“ SearchView”。

Answer 2

这是一个简单的空指针异常。您没有共享全部错误，但是在错误结束时，您获得了错误来源所在的行号。只需单击该行，编译器就会自动定向到该行。确保没有初始化就没有使用任何变量。写list<Weather> = new ArrayList()，而不仅仅是写list<Weather>。

我已经实现了与recyclerview一起使用的searchview，但是出现错误？

2 个答案: