在Android中讀取.txt文件

Question

我有我的txt文件與JSON內容和這個文件的大小是88KB，現在我正在嘗試讀取此文件內容，但我得到了Nullpointerexception錯誤 這裏是我的代碼和logcat。請幫忙。

我後我解析JSONcode

InputStream stream = getResources().openRawResource(R.raw.topiclist); 
readTextFile(stream);//While debugging i got sourcenotfound on this line 


public static void readTextFile(InputStream is) 
{ 
    BufferedReader reader = new BufferedReader(new InputStreamReader(is)); 
    StringBuilder sb = new StringBuilder(); 

    String line = null; 
    try { 
     while ((line = reader.readLine()) != null) { 
      sb.append((line + "\n")); 
     } 
    } catch (IOException e) { 
     Log.w("LOG", e.getMessage()); 
    } finally { 
     try { 
      is.close(); 
     } catch (IOException e) { 
      Log.w("LOG", e.getMessage()); 
     } 
    } 
    topic=new GetTopicList(); 
    topic.parseJson(sb.toString());  

} 

logcat的

02-27 22:29:45.170: E/AndroidRuntime(2099): FATAL EXCEPTION: main 
    02-27 22:29:45.170: E/AndroidRuntime(2099): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.postreply/com.example.postreply.PostReply}: java.lang.NullPointerException 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.ActivityThread.access$600(ActivityThread.java:130) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.os.Handler.dispatchMessage(Handler.java:99) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.os.Looper.loop(Looper.java:137) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.ActivityThread.main(ActivityThread.java:4745) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at java.lang.reflect.Method.invokeNative(Native Method) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at java.lang.reflect.Method.invoke(Method.java:511) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at dalvik.system.NativeStart.main(Native Method) 
    02-27 22:29:45.170: E/AndroidRuntime(2099): Caused by: java.lang.NullPointerException 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at com.tomovwgti.socketio.SQLiteAdapter.openToWrite(SQLiteAdapter.java:56) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at com.tomovwgti.socketio.GetTopicList.parseJson(GetTopicList.java:126) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at com.example.postreply.PostReply.readTextFile(PostReply.java:200) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at com.example.postreply.PostReply.onCreate(PostReply.java:86) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.Activity.performCreate(Activity.java:5008) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 
    02-27 22:29:45.170: E/AndroidRuntime(2099):  ... 11 more 

parseJson（）：

public void parseJson(String response) 
    { 

     sqlAdapter=new SQLiteAdapter(context); 

     sqlAdapter.openToWrite(); 

     //long s=sqlAdapter.countjournals(); 


     JSONArray ja = null; 
     JSONObject json=null; 
     String status = null; 

      try { 
       json=new JSONObject(response); 
       status=json.getString("Status"); 

      } catch (JSONException e1) { 
       // TODO Auto-generated catch block 
       e1.printStackTrace(); 
      } 

      if(status.equals("0")) 
      { 
       String addtopics; 
       try { 
        addtopics = json.getString("AddTopics"); 
        ja = new JSONArray(addtopics); 
       } catch (JSONException e1) { 
        // TODO Auto-generated catch block 
        e1.printStackTrace(); 
       } 


       int len=ja.length(); 

       topicid = new String[len]; 
       topic = new String[len]; 
       field = new String[len]; 
       subject = new String[len]; 
       topiccode = new String[len]; 
       topicStatus = new String[len]; 


       JSONObject jo; 

       for(int j=0;j<len;j++) 
       { 

        try 
        { 
         jo = ja.getJSONObject(j); 
         topicid[j] = jo.getString("TopicID"); 
         field[j] = jo.getString("Field"); 
         subject[j] = jo.getString("Subject"); 
         topic[j] = jo.getString("Subcategory"); 
         topiccode[j] = jo.getString("TopicCode"); 
         topicStatus[j] = jo.getString("TopicStatus"); 


         sqlAdapter.insert(topicid[j], field[j], subject[j], topic[j], topiccode[j], topicStatus[j]); 

        } catch (JSONException e) { 
         // TODO Auto-generated catch block 
         e.printStackTrace(); 
        } 

       } 
       sqlAdapter.close(); 
      } 

    } 

Answer 1

被這條線所產生的錯誤：

sqlAdapter.openToWrite(); 

這意味着sqlAdapter是null。這可能是因爲它的初始化在

sqlAdapter=new SQLiteAdapter(context); 

返回一個null值。你需要找出爲什麼會發生並修復它。