在软键盘打开/关闭之前，RecyclerView 不会更新并显示在屏幕上
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【中文标题】在软键盘打开/关闭之前，RecyclerView 不会更新并显示在屏幕上【英文标题】：RecyclerView doesn't Update and shows on screen until Soft Keyboard is Open/Close 【发布时间】：2022-01-04 01:58:10 【问题描述】：我的 RecyclerView 有一个问题 - 按下按钮后它不会在主屏幕上更新。它只能在关闭/打开软踢板后出现。我在这里看了很多解决方案，但没有任何帮助。我只有一个简单的应用程序，它向服务器发送请求“字符串”并获取一个 JSON 对象，然后将其插入 RecyclerView。但是 RecyclerView 中的数据不会立即出现。我陷入僵局。帮帮我。
activity_main.xml 中的代码：
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
android:background="@drawable/sky"
tools:context=".MainActivity">
<EditText
android:id="@+id/editTextRequestCity"
android:layout_
android:layout_
android:hint="@string/write_name_of_city_or_index"
android:inputType="textPersonName"
android:maxLength="30"
android:minHeight="48dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toTopOf="@+id/recyclerViewListForecast"
app:layout_constraintEnd_toStartOf="@+id/buttonShowWeather"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/buttonShowWeather"
android:layout_
android:layout_
android:background="@drawable/search_city"
android:onClick="onClickShowWeather"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toTopOf="@+id/recyclerViewListForecast"
app:layout_constraintStart_toEndOf="@+id/editTextRequestCity"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerViewListForecast"
app:layoutManager="LinearLayoutManager"
android:layout_
android:layout_
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/editTextRequestCity"/>
</androidx.constraintlayout.widget.ConstraintLayout>
weather_item.xml 中的代码：
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/cardViewItem"
android:layout_
android:layout_
android:layout_margin="1dp"
app:cardCornerRadius="1dp">
<LinearLayout
android:layout_
android:layout_
android:orientation="vertical">
<TextView
android:id="@+id/textViewDate"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:background="#00FFFFFF"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewTime"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewFallout"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewDegree"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewPressure"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewHumidity"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewSpeedWind"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewGustWind"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textColor="@color/black"
android:textSize="15sp" />
<TextView
android:id="@+id/textViewDirectionWind"
android:layout_
android:layout_
android:layout_marginTop="2dp"
android:gravity="center"
android:textSize="15sp" />
</LinearLayout>
</androidx.cardview.widget.CardView>
WeatherItem 中的代码：
package com.example.forecast;
public class WeatherItem
private String date;
private String time;
private String fallout;
private String degree;
private String pressure;
private String humidity;
private String speedWind;
private String gustWind;
private String directionWind;
public WeatherItem(String date, String time, String fallout, String degree, String pressure, String humidity, String speedWind, String gustWind, String directionWind)
this.date = date;
this.time = time;
this.fallout = fallout;
this.degree = degree;
this.pressure = pressure;
this.humidity = humidity;
this.speedWind = speedWind;
this.gustWind = gustWind;
this.directionWind = directionWind;
public String getDate()
return date;
public String getTime()
return time;
public String getFallout()
return fallout;
public String getDegree()
return degree;
public String getPressure()
return pressure;
public String getHumidity()
return humidity;
public String getSpeedWind()
return speedWind;
public String getGustWind()
return gustWind;
public String getDirectionWind()
return directionWind;
WeatherAdapter 中的代码：
package com.example.forecast;
public class WeatherAdapter extends RecyclerView.Adapter<WeatherAdapter.WeatherViewHolder>
public ArrayList<WeatherItem> weatherItems;
Context context;
public WeatherAdapter(Context context, ArrayList <WeatherItem> weatherItems)
this.context = context;
this.weatherItems = weatherItems;
@NonNull
@Override
public WeatherViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType)
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.weather_item, parent, false);
return new WeatherViewHolder(view);
@Override
public void onBindViewHolder(final WeatherViewHolder holder, int position)
WeatherItem weatherItem = weatherItems.get(position);
holder.textViewDate.setText(weatherItem.getDate());
holder.textViewTime.setText(weatherItem.getTime());
holder.textView.setText(weatherItem.getFallout());
holder.textViewDegree.setText(weatherItem.getDegree());
holder.textViewPressure.setText(weatherItem.getPressure());
holder.textViewHumidity.setText(weatherItem.getHumidity());
holder.textViewSpeedWind.setText(weatherItem.getSpeedWind());
holder.textViewGustWind.setText(weatherItem.getGustWind());
holder.textViewDirectionWind.setText(weatherItem.getDirectionWind());
@Override
public int getItemCount()
return weatherItems.size();
static class WeatherViewHolder extends RecyclerView.ViewHolder
private TextView textViewDate;
private TextView textViewTime;
private TextView textView;
private TextView textViewDegree;
private TextView textViewPressure;
private TextView textViewHumidity;
private TextView textViewSpeedWind;
private TextView textViewGustWind;
private TextView textViewDirectionWind;
public WeatherViewHolder(@NonNull View itemView)
super(itemView);
textViewDate = itemView.findViewById(R.id.textViewDate);
textViewTime = itemView.findViewById(R.id.textViewTime);
textView = itemView.findViewById(R.id.textViewFallout);
textViewDegree = itemView.findViewById(R.id.textViewDegree);
textViewPressure = itemView.findViewById(R.id.textViewPressure);
textViewHumidity = itemView.findViewById(R.id.textViewHumidity);
textViewSpeedWind = itemView.findViewById(R.id.textViewSpeedWind);
textViewGustWind = itemView.findViewById(R.id.textViewGustWind);
textViewDirectionWind = itemView.findViewById(R.id.textViewDirectionWind);
最后是我在 MainActivity 中的代码：
public class MainActivity extends AppCompatActivity
EditText editTextRequestCity;
private RecyclerView recyclerViewListForecast;
WeatherAdapter adapter;
private ArrayList<WeatherItem> weatherItems = new ArrayList<>();
private final String WEATHER_URL = "https://api.openweathermap.org/data/2.5/forecast?q=%s&lang=ru&units=metric&appid=ce288368c68807e060c17369bfbef3b3";
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextRequestCity = findViewById(R.id.editTextRequestCity);
recyclerViewListForecast = findViewById(R.id.recyclerViewListForecast);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerViewListForecast.setLayoutManager(linearLayoutManager);
adapter = new WeatherAdapter(getApplicationContext(), weatherItems = new ArrayList<>());
recyclerViewListForecast.setAdapter(adapter);
public void onClickShowWeather(View view)
InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
weatherItems.clear();
adapter.notifyDataSetChanged();
String city = editTextRequestCity.getText().toString().trim();
String request = String.format(WEATHER_URL,city);
DownLoadWeatherTask task = new DownLoadWeatherTask();
task.execute(request);
private class DownLoadWeatherTask extends AsyncTask<String, Void, String>
@Override
protected String doInBackground(String... strings)
URL url = null;
HttpURLConnection urlConnection = null;
StringBuilder result = new StringBuilder();
try
url = new URL(strings[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader reader = new BufferedReader(inputStreamReader);
String line = reader.readLine();
while (line != null)
result.append(line);
line = reader.readLine();
return result.toString();
catch (MalformedURLException e)
e.printStackTrace();
catch (IOException e)
e.printStackTrace();
finally
if (urlConnection != null)
urlConnection.disconnect();
return null;
@Override
protected void onPostExecute(String s)
super.onPostExecute(s);
if (s != null)
try
JSONObject jsonObjectMain = new JSONObject(s);
JSONArray jsonArray = jsonObjectMain.getJSONArray("list");
for (int i = 0; i < jsonArray.length(); i++)
ArrayList<WeatherItem> weatherItemDay = new ArrayList<>();
JSONObject jsonObjectDay = jsonArray.getJSONObject(i);
String dateTime = jsonObjectDay.getString("dt_txt");
String date = dateTime.substring(0, 10).trim();
String time = dateTime.substring(11, 16).trim();
String fallout = jsonObjectDay.getJSONArray("weather").getJSONObject(0).getString("description").trim();
String degree = String.format("" + jsonObjectDay.getJSONObject("main").getInt("temp")).trim();
String pressure = String.format("" + jsonObjectDay.getJSONObject("main").getInt("pressure")).trim();
String humidity = String.format("" + jsonObjectDay.getJSONObject("main").getInt("humidity")).trim();
String speedWind = String.format("" + jsonObjectDay.getJSONObject("wind").getInt("speed")).trim();
String gustWind = String.format("" + jsonObjectDay.getJSONObject("wind").getInt("gust")).trim();
String directionWind = String.format("" + jsonObjectDay.getJSONObject("wind").getInt("deg")).trim();
weatherItems.add(new WeatherItem(date, time, fallout, degree, pressure, humidity, speedWind, gustWind, directionWind));
catch (JSONException e)
e.printStackTrace();
【问题讨论】：
【参考方案1】：当您向列表中添加新项目时，请致电 notifyDataSetChanged()。根据您的代码，这需要在 onPostExecute 中为您完成。
您已经在 onClick 中调用了notifyDataSetChanged()，但这是在任务完成之前，因此该项目不会显示，因为它尚未添加到列表中。
【讨论】：
是的，谢谢@Naveed！我在 onPostExecute 方法的末尾添加了几行：adapter = new WeatherAdapter(getApplicationContext(), weatherItems); recyclerViewListForecast.setAdapter(adapter); adapter.notifyDataSetChanged();，它对我有帮助！以上是关于在软键盘打开/关闭之前，RecyclerView 不会更新并显示在屏幕上的主要内容，如果未能解决你的问题，请参考以下文章
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