首先很抱歉我的英語不好。我的問題是，我正在嘗試使用 Wea??ther API 制作一個 Weather 應用程式。我想使用 recyclerview 配接器顯示 5 天的預測。我將資料添加到 arraylist，這是我從 API 獲取的，它應該轉到我的配接器類。它需要在那里顯示添加到 arraylist 的資料，但它沒有，并且 arraylist 大小始終為零。
我的 recyclerview 類是預測的
oncreate
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_forecast);
Intent intent = getIntent();
Latitude = intent.getDoubleExtra("lat",0);
Longitude = intent.getDoubleExtra("long",0);
System.out.println("LAT?TUDE " Latitude " Longitude " Longitude);//i just experimented to
check if latitude and
longitude come
init();
}
在里面（）
public void init(){
arrayList = new ArrayList<>();
forecast_back_icon = findViewById(R.id.forecast_back_icon);
recyclerviewforecast = findViewById(R.id.RecyclerviewForecast);
get_forecast_data(Latitude,Longitude);
forecastAdapter = new ForecastAdapter(arrayList);
recyclerviewforecast.setAdapter(forecastAdapter);
recyclerviewforecast.setLayoutManager(new LinearLayoutManager(forecast.this));
forecast_back_icon();
}
get_forecast_data() 函式
public void get_forecast_data(Double Lat, Double Long){
//EXAMPLE URL
//https://api.openweathermap.org/data/2.5/weather?lat={lat}&lon={lon}&appid={API key}
API_KEY_FORECAST = "c29ecfafd4a70caad8fee38d6054bfc7";
URL_FORECAST = "https://api.openweathermap.org/data/2.5/onecall?lat=" Lat "&lon=" Long "&exclude=current,minutely,hourly,alerts&appid=" API_KEY_FORECAST;
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, URL_FORECAST, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray daily = response.getJSONArray("daily");
for(int i=0;i<daily.length();i ){
String temp = daily.getJSONObject(i).getJSONObject("temp").getString("day");
String feels_like = daily.getJSONObject(i).getJSONObject("feels_like").getString("day");
String pressure = daily.getJSONObject(i).getString("pressure");
String humidity = daily.getJSONObject(i).getString("humidity");
String wind_speed = daily.getJSONObject(i).getString("wind_speed");
String icon = daily.getJSONObject(i).getJSONArray("weather").getJSONObject(0).getString("icon");
String description = daily.getJSONObject(i).getJSONArray("weather").getJSONObject(0).getString("description");
arrayList.add(new RecyclerviewModel(temp,humidity,feels_like,pressure,description,wind_speed,icon));
}
}
catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
queue.add(request);
System.out.println("forecast class arraylist size : --> " arrayList.size());
}
當我在底部檢查時，arraylist 的大小為零
我的預測配接器類
public class ForecastAdapter extends RecyclerView.Adapter<ForecastAdapter.MyForecastViewHolder> {
ArrayList<RecyclerviewModel> ForecastArraylist;
public ForecastAdapter(ArrayList<RecyclerviewModel> ForecastArraylist){
this.ForecastArraylist = ForecastArraylist;
System.out.println("ForecastAdapter arraylist size : --- > " ForecastArraylist.size());
}
@NonNull
@Override
public MyForecastViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
RecyclerviewForecastRowBinding recyclerviewForecastRowBinding = RecyclerviewForecastRowBinding.inflate(LayoutInflater.from(parent.getContext()),parent,false);
return new MyForecastViewHolder(recyclerviewForecastRowBinding);
}
@Override
public void onBindViewHolder(@NonNull MyForecastViewHolder holder, int position) {
System.out.println("we are in onbindviewholder.... ");
Double temperature = Double.parseDouble(ForecastArraylist.get(position).getTemperature()) - 273.15;
System.out.println(temperature);
Double feels_like = Double.parseDouble(ForecastArraylist.get(position).getFeels_like()) - 273.15;
holder.binding.txtRecyclerviewTemp.setText(temperature.toString().substring(0,4) "°");
holder.binding.txtRecyclerviewFeelslike.setText(feels_like.toString().substring(0,4) "°");
holder.binding.txtRecyclerviewHumidity.setText("%" ForecastArraylist.get(position).getHumadity());
holder.binding.txtRecyclerviewPressure.setText(ForecastArraylist.get(position).getPressure() "hPa");
holder.binding.txtRecyclerviewWindSpeed.setText(ForecastArraylist.get(position).getWind_speed() "km/h");
holder.binding.txtRecyclerviewCloud.setText(ForecastArraylist.get(position).getDescription());
String icon_id = ForecastArraylist.get(position).getId();
load_weather_icon(icon_id,holder);
}
@Override
public int getItemCount() {
return ForecastArraylist.size();
}
public class MyForecastViewHolder extends RecyclerView.ViewHolder{
private RecyclerviewForecastRowBinding binding;
public MyForecastViewHolder(@NonNull RecyclerviewForecastRowBinding binding) {
super(binding.getRoot());
this.binding = binding;
}
}
public void load_weather_icon(String id,MyForecastViewHolder holder ){
int id1 = Integer.valueOf(id);
if(id1>=200 && id1 <= 232){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.thunderstorm);
}
else if(id1>=300 && id1<= 321){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.showerrain);
}
else if(id1>=500 && id1<= 504){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.rain);
}
else if(id1 == 511){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.snow);
}
else if(id1>=520 && id1<= 531){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.showerrain);
}
else if(id1>=600 && id1<= 622){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.snow);
}
else if(id1>=701 && id1<= 781){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.mist);
}
else if(id1 == 800 ){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.clearsky);
}
else if(id1 == 801){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.fewclouds);
}
else if(id1 == 802){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.scatteredclouds);
}
else if(id1 == 803){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.brokenclouds);
}
else if(id1 == 804){
holder.binding.recyclerviewCloudImg.setBackgroundResource(R.drawable.brokenclouds);
}
}
}
我在我的預測配接器中看不到“我們在 onbindviewholder”
預測xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".forecast"
android:orientation="vertical"
android:id="@ id/forecastLayout">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:id="@ id/Toolbarcities">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@ id/toolbarconstraintforecast"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.appcompat.widget.Toolbar
android:id="@ id/MyToolbarforecast"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="?attr/actionBarTheme"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:titleTextColor="@color/white"
>
<ImageView
android:id="@ id/forecast_back_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/cities_back_icon"
></ImageView>
</androidx.appcompat.widget.Toolbar>
</androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.appbar.AppBarLayout>
<androidx.recyclerview.widget.RecyclerView
android:id="@ id/RecyclerviewForecast"
android:layout_width="match_parent"
android:layout_height="match_parent" />
uj5u.com熱心網友回復：
這里的問題是，在處理 Volley 請求并填充陣列串列之前，您已經使用空陣列串列創建了配接器并將其分配給 Recyclerview。有 2 種方法可以解決此問題。首先是創建配接器并在 Volley 請求的 OnResponse 方法中設定配接器。或者，您可以在配接器中創建一個方法來更新陣列串列并通知配接器資料集已更改。我希望你能理解這一點。
第一個是最簡單的
轉載請註明出處，本文鏈接：https://www.uj5u.com/ruanti/334808.html