Question

我的txt文件包含JSON内容，此文件的大小为88KB，现在我正在尝试读取此文件内容，但我收到Nullpointerexception错误这是我的代码和logcat。请帮忙。

我发布了我的解析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

 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

此行正在生成错误：

sqlAdapter.openToWrite();

表示sqlAdapter为null。这可能是因为它在

中初始化

sqlAdapter=new SQLiteAdapter(context);

返回null值。你需要找出发生这种情况的原因并加以解决。

在Android中读取.txt文件

1 个答案: