RecyclerCardview没有显示任何内容

Question

我正在尝试从天气api传递数据并使其成为recyclerView和cardView，但我不知道为什么我的活动没有显示任何内容，我不知道为什么不工作。任何人都可以帮助我，谢谢先进

********这是我的代码***********

  

DailyWeatherInfo.java

private Daily mDaily;
    private RecyclerView recyclerView;
    private LinearLayoutManager layoutManager;
    private CustomAdapter adapter;
    private List<Daily> data_list;
    private double latitude;
    private double longitude;


    public DailyWeatherInfo() {
    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_daily_weather_info);

        recyclerView = findViewById(R.id.recyclerView);
        data_list = new ArrayList<>();
        load_weather_info(37.8267,-122.4233);
        layoutManager = new LinearLayoutManager(this);
        adapter = new CustomAdapter(this,data_list);
        adapter.notifyDataSetChanged();
        recyclerView.setAdapter(adapter);

        //getForcus(37.8267,-122.4233);





    }

    private void load_weather_info(final double latitude, final double longitude) {

        //this.latitude = latitude;
        //this.longitude = longitude;
        AsyncTask<Integer, Void, Void> task = new AsyncTask<Integer, Void, Void>() {
            @Override
            protected Void doInBackground(Integer... integers) {

                String apiKey = "--------------------------------";
                String forecastUrl = "https://api.darksky.net/forecast/" + apiKey +
                        "/" + latitude + "," + longitude;
                OkHttpClient client = new OkHttpClient();
                Request request = new Request.Builder()
                        .url(forecastUrl)
                        .build();
                try {
                    Response response = client.newCall(request).execute();
                    JSONArray array = new JSONArray(response.body().string());

                    for (int i = 0; i<array.length(); i++){
                        JSONObject jsonObject = array.getJSONObject(i);
                        JSONObject daily = jsonObject.getJSONObject("daily");
                        JSONObject mDaily = daily.getJSONObject("data");
                        Daily daily1 = new Daily(mDaily.getString("summary"), mDaily.getString("icon"),
                                mDaily.getDouble("precipProbability"), mDaily.getLong("time"));

                        data_list.add(daily1);

                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (JSONException e) {
                    e.printStackTrace();
                }

                return null;
            }


            @Override
            protected void onPostExecute(Void aVoid) {
                super.onPostExecute(aVoid);
            }
        };

        task.execute((int) latitude, (int) longitude);
    }

  

Daily.java

public class Daily {

    private String nIcon;
    private String nSummary;
    private String nTimeZone;
    private Long nTimeStamp;
    private Double nPrecipPro;

    public Daily(String nSummary, String nIcon, double nPrecipPro, long nTimeStamp ){
        this.nSummary = nSummary;
        this.nIcon = nIcon;
        this.nPrecipPro = nPrecipPro;
        this.nTimeStamp = nTimeStamp;
    }


    public String getnTimeZone() {
        return nTimeZone;
    }

    public void setnTimeZone(String nTimeZone) {
        this.nTimeZone = nTimeZone;
    }


    public String getnIcon() {
        return nIcon;
    }

    public int getIconId(){
        //clear-day, clear-night, rain, snow, sleet, wind, fog, cloudy, partly-cloudy-day, or partly-cloudy-night
        int iconId = R.drawable.clear_day;

        if (nIcon.equals("clear-day")){
            iconId = R.drawable.clear_day;
        }else if (nIcon.equals("clear-night")) {
            iconId = R.drawable.clear_night;
        }
        else if (nIcon.equals("rain")) {
            iconId = R.drawable.rain;
        }
        else if (nIcon.equals("snow")) {
            iconId = R.drawable.snow;
        }
        else if (nIcon.equals("sleet")) {
            iconId = R.drawable.sleet;
        }
        else if (nIcon.equals("wind")) {
            iconId = R.drawable.wind;
        }
        else if (nIcon.equals("fog")) {
            iconId = R.drawable.fog;
        }
        else if (nIcon.equals("cloudy")) {
            iconId = R.drawable.cloudy;
        }
        else if (nIcon.equals("partly-cloudy-day")) {
            iconId = R.drawable.partly_cloudy;
        }
        else if (nIcon.equals("partly-cloudy-night")) {
            iconId = R.drawable.cloudy_night;
        }
        return iconId;
    }

    public void setnIcon(String nIcon) {
        this.nIcon = nIcon;
    }




    public String getnSummary() {
        return nSummary;
    }

    public void setnSummary(String nSummary) {
        this.nSummary = nSummary;
    }

    public Long getnTimeStamp() {
        return nTimeStamp;
    }

    public String getFormattedTime(){
        SimpleDateFormat formatter = new SimpleDateFormat("h:mm a");
        formatter.setTimeZone(TimeZone.getTimeZone(getnTimeZone()));
        Date dateTime = new Date(getnTimeStamp()*1000);
        String timeString = formatter.format(dateTime);
        return timeString;
    }

    public void setnTimeStamp(Long nTimeStamp) {
        this.nTimeStamp = nTimeStamp;
    }

    public Double getnPrecipPro() {
        return nPrecipPro;
    }

    public void setnPrecipPro(Double nPrecipPro) {
        this.nPrecipPro = nPrecipPro;
    }


}

  

CustomAdapter.java

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {

    private Context context;
    private List<Daily> myDaily;



    public CustomAdapter(Context context, List<Daily> myDaily){

        this.context = context;
        this.myDaily = myDaily;
        notifyDataSetChanged();

    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_view,parent,false);

        return new ViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

        holder.cSummary.setText(myDaily.get(position).getnSummary());
        holder.cPrecipProability.setText(myDaily.get(position).getnPrecipPro() + "");
        holder.cDate.setText(myDaily.get(position).getFormattedTime());
        holder.cImage.setImageResource(myDaily.get(position).getIconId());

    }

    @Override
    public int getItemCount() {
        return myDaily.size();
    }


    public class ViewHolder extends RecyclerView.ViewHolder {

        public TextView cDate;
        public ImageView cImage;
        public TextView cSummary;
        public TextView cPrecipProability;


        public ViewHolder(View itemView) {
            super(itemView);
            cDate = itemView.findViewById(R.id.txtDate);
            cSummary = itemView.findViewById(R.id.txtSummary);
            cPrecipProability = itemView.findViewById(R.id.txtRainChance);
            cImage = itemView.findViewById(R.id.weather_icon);
        }
    }
}

  

card_view xml

我的xml文件有什么问题吗？

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
     android:layout_height="wrap_content">

<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="100dp">


    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="100dp">

        <ImageView
            android:id="@+id/weather_icon"
            android:layout_width="70dp"
            android:layout_height="70dp"
            android:layout_marginLeft="12dp"
            android:layout_marginTop="15dp" />

        <TextView
            android:id="@+id/txtDate"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/weather_icon"
            android:layout_marginLeft="18dp"
            android:layout_marginStart="18dp"
            android:layout_toEndOf="@+id/weather_icon"
            android:layout_toRightOf="@+id/weather_icon"
            android:text="2018/04/06,  Friday"
            android:textSize="15dp" />

        <TextView
            android:id="@+id/txtSummary"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/txtDate"
            android:layout_alignStart="@+id/txtDate"
            android:layout_centerVertical="true"
            android:text="Mostly cloudy throughout the day."
            android:textSize="20dp" />

        <TextView
            android:id="@+id/txtRainChance"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/weather_icon"
            android:layout_alignLeft="@+id/txtSummary"
            android:layout_alignStart="@+id/txtSummary"
            android:text="Rain of Chance : 65%" />


    </RelativeLayout>

</android.support.v7.widget.CardView>
</LinearLayout>

Answer 1

您忘了 setLayoutManager(); 到recyclerView检查

recyclerView.setLayoutManager(layoutManager);

修改

网络操作需要一些时间来执行操作，以便在从API

获取数据后设置适配器

试试这个

    data_list = new ArrayList<>();
    recyclerView = findViewById(R.id.recyclerView);
    layoutManager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(layoutManager);
    adapter = new CustomAdapter(this,data_list);
    recyclerView.setAdapter(adapter);
    load_weather_info(37.8267,-122.4233);

更改 load_weather_info 方法，如下面的代码

private void load_weather_info(final double latitude, final double longitude) {

        //this.latitude = latitude;
        //this.longitude = longitude;
        AsyncTask<Integer, Void, Void> task = new AsyncTask<Integer, Void, Void>() {
            @Override
            protected Void doInBackground(Integer... integers) {

                String apiKey = "--------------------------------";
                String forecastUrl = "https://api.darksky.net/forecast/" + apiKey +
                        "/" + latitude + "," + longitude;
                OkHttpClient client = new OkHttpClient();
                Request request = new Request.Builder()
                        .url(forecastUrl)
                        .build();
                try {
                    Response response = client.newCall(request).execute();
                    JSONArray array = new JSONArray(response.body().string());

                    for (int i = 0; i<array.length(); i++){
                        JSONObject jsonObject = array.getJSONObject(i);
                        JSONObject daily = jsonObject.getJSONObject("daily");
                        JSONObject mDaily = daily.getJSONObject("data");
                        Daily daily1 = new Daily(mDaily.getString("summary"), mDaily.getString("icon"),
                                mDaily.getDouble("precipProbability"), mDaily.getLong("time"));

                        data_list.add(daily1);

                    }
                 adapter.notifyDataSetChanged();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (JSONException e) {
                    e.printStackTrace();
                }

                return null;
            }


            @Override
            protected void onPostExecute(Void aVoid) {
                super.onPostExecute(aVoid);
            }
        };

        task.execute((int) latitude, (int) longitude);
    }

Answer 2

您尚未通知adapter有关数据更改的信息。

 for (int i = 0; i<array.length(); i++){
                        JSONObject jsonObject = array.getJSONObject(i);
                        JSONObject daily = jsonObject.getJSONObject("daily");
                        JSONObject mDaily = daily.getJSONObject("data");
                        Daily daily1 = new Daily(mDaily.getString("summary"), mDaily.getString("icon"),
                                mDaily.getDouble("precipProbability"), mDaily.getLong("time"));

                        data_list.add(daily1);

                    }
   adapter.notifyDataSetChanged(); //notify here

Answer 3

大部分错误已经指出。只是纠正它们。

UPPER(FORMAT(yourDate, 'MMM-yyyy'))

按如下方式通知适配器。

data_list = new ArrayList<>();
recyclerView = findViewById(R.id.recyclerView);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
adapter = new CustomAdapter(this,data_list);
recyclerView.setAdapter(adapter);
load_weather_info(37.8267,-122.4233);

PS：在这里，您应该使用private void load_weather_info(final double latitude, final double longitude) { AsyncTask<Integer, Void, Void> task = new AsyncTask<Integer, Void, Void>() { @Override protected Void doInBackground(Integer... integers) { String apiKey = "--------------------------------"; String forecastUrl = "https://api.darksky.net/forecast/" + apiKey + "/" + latitude + "," + longitude; OkHttpClient client = new OkHttpClient(); Request request = new Request.Builder() .url(forecastUrl) .build(); try { Response response = client.newCall(request).execute(); JSONArray array = new JSONArray(response.body().string()); for (int i = 0; i<array.length(); i++){ JSONObject jsonObject = array.getJSONObject(i); JSONObject daily = jsonObject.getJSONObject("daily"); JSONObject mDaily = daily.getJSONObject("data"); Daily daily1 = new Daily(mDaily.getString("summary"), mDaily.getString("icon"), mDaily.getDouble("precipProbability"), mDaily.getLong("time")); data_list.add(daily1); } recyclerView.post(new Runnable() { @Override public void run() { adapter.notifyDataSetChanged(); } }); } catch (IOException e) { e.printStackTrace(); } catch (JSONException e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(Void aVoid) { super.onPostExecute(aVoid); } }; task.execute((int) latitude, (int) longitude); } 来获取返回的数据集并处理onPostExecute()。