java - Android致命异常错误

Question

我正在尝试从 API 获取数据。执行代码时出现以下错误:

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.smitsanghvi.moviedb, PID: 9844
                  java.lang.IndexOutOfBoundsException: Invalid index 7, size is 0
                      at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
                      at java.util.ArrayList.get(ArrayList.java:308)
                      at com.example.smitsanghvi.moviedb.MainActivity$CheckConnectionStatus.onPostExecute(MainActivity.java:104)
                      at com.example.smitsanghvi.moviedb.MainActivity$CheckConnectionStatus.onPostExecute(MainActivity.java:44)
                      at android.os.AsyncTask.finish(AsyncTask.java:651)
                      at android.os.AsyncTask.-wrap1(AsyncTask.java)
                      at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:148)
                      at android.app.ActivityThread.main(ActivityThread.java:5417)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Application terminated.

MainActivity.java

• 它连接到 API 并尝试获取数据。

• 下面的代码 fragment 。

  public class MainActivity extends AppCompatActivity {  
  
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);    
      new CheckConnectionStatus().execute("https://api.themoviedb.org/3/tv/popular?api_key=(IamNotProvidingInQuestion)&language=en-US&page=1");
  }
  
      //created an asynchronous task
  class CheckConnectionStatus extends AsyncTask<String, Void, String> {
  
  protected void onPreExecute(){
      super.onPreExecute();
  
  }
      @Override
      protected String doInBackground(String... params) {
          URL url = null;
          try {
              url = new URL(params[0]);
          } catch (MalformedURLException e) {
              e.printStackTrace();
          }
          try {
              HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
  
  
              InputStream inputStream=urlConnection.getInputStream();
              BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(inputStream));
  
              String s=bufferedReader.readLine();
              bufferedReader.close();
              return s;
  
          } catch (IOException e) {
              Log.e("Error:", e.getMessage(), e);
          }
          return null;
  
      }
  
      protected void onPostExecute(String s) {
          super.onPostExecute(s);
          //created json object to read and parse json
  
          JSONObject jsonObject=null;
          try {
              jsonObject=new JSONObject(s);
              //creating an arraylist for the tv season info
              ArrayList<SeasonInfo>newlist=new ArrayList<>();
  
  
              //reading objects from production companies as its an array
              JSONArray jsonArray=jsonObject.getJSONArray("results");
              //iterating to get the id from the company name
              for(int i=0;i<jsonArray.length();i++)
              {
  
                  JSONObject object=jsonArray.getJSONObject(i);
                  SeasonInfo seasonInfo=new SeasonInfo();
                  seasonInfo.setOriginal_name(object.getString("original_name"));
                  seasonInfo.setOverview(object.getString("overview"));
                  seasonInfo.setPoster_path(object.getString("poster_path"));
                  seasonInfo.setOriginal_language(object.getString("original_language"));
                  seasonInfo.setFirst_air_date(object.getString("first_air_date"));
  
  
              }
              Log.i("List:",newlist.get(0).getOverview());
  
          } catch (JSONException e) {
              e.printStackTrace();
          }
      }
  
  }
  

  }

SeasonInfo.java

• 保存 JSON 数据。

• 下面的代码 fragment 。

  public class SeasonInfo {
  
  public  String original_name;
  public String overview;
  public  String poster_path;
  public String original_language;
  public String first_air_date;
  
  public String getPoster_path() {
      return poster_path;
  }
  
  public void setPoster_path(String poster_path) {
      this.poster_path = poster_path;
  }
  
  
  
  public String getOriginal_name() {
      return original_name;
  }
  
  public void setOriginal_name(String original_name) {
      this.original_name = original_name;
  }
  
  public String getOverview() {
      return overview;
  }
  
  public void setOverview(String overview) {
      this.overview = overview;
  }
  
  public String getOriginal_language() {
      return original_language;
  }
  
  public void setOriginal_language(String original_language) {
      this.original_language = original_language;
  }
  
  public String getFirst_air_date() {
      return first_air_date;
  }
  
  public void setFirst_air_date(String first_air_date) {
      this.first_air_date = first_air_date;
  }
  

  }

这是我在我的应用程序中使用的网站上的 JSON 数据。我在此处附加的 JSON 数据并不完整，只是第一部分，以便您可以更好地理解。

 [{
"page": 1,
"total_results": 20024,
"total_pages": 1002,
"results": [
{
"original_name": "The Big Bang Theory",
"genre_ids": [],
"name": "The Big Bang Theory",
"popularity": 294.657,
"origin_country": [],
"vote_count": 3133,
"first_air_date": "2007-09-24",
"backdrop_path": "/nGsNruW3W27V6r4gkyc3iiEGsKR.jpg",
"original_language": "en",
"id": 1418,
"vote_average": 6.8,
"overview": "The Big Bang Theory is centered on five characters living in Pasadena, California: roommates Leonard Hofstadter and Sheldon Cooper; Penny, a waitress and aspiring actress who lives across the hall; and Leonard and Sheldon's equally geeky and socially awkward friends and co-workers, mechanical engineer Howard Wolowitz and astrophysicist Raj Koothrappali. The geekiness and intellect of the four guys is contrasted for comic effect with Penny's social skills and common sense.",
"poster_path": "/ooBGRQBdbGzBxAVfExiO8r7kloA.jpg"
}]

Answer 1

尝试注释这一行:

Log.i("List:",newlist.get(0).getOverview());

因为您从未向 newlist 数组添加任何值，而您却试图获取一些值。