在service中使用ContentResolver报错

Question

问题描述 在service中使用ContentResolver报错，报错如下，请问如何解决？ 报错 FATAL EXCEPTION: main Process: com.mp.mmedicaplayer, PID: 16990 java.lang.RuntimeException: Unable to instantiate service com.mp.mmedicaplayer.service.MusicService: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.ContentResolver android.content.Context.getContentResolver()' on a null object reference at android.app.ActivityThread.handleCreateService(ActivityThread.java:3390) at android.app.ActivityThread.-wrap5(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1753) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:159) at android.app.ActivityThread.main(ActivityThread.java:6385) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1096) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:883) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.ContentResolver android.content.Context.getContentResolver()' on a null object reference at com.mp.mmedicaplayer.service.MusicService.getMusicToArray(MusicService.java:211) at com.mp.mmedicaplayer.service.MusicService.<init>(MusicService.java:48) at java.lang.Class.newInstance(Native Method) at android.app.ActivityThread.handleCreateService(ActivityThread.java:3387) at android.app.ActivityThread.-wrap5(ActivityThread.java)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1753)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:159)  at android.app.ActivityThread.main(ActivityThread.java:6385)  at java.lang.reflect.Method.invoke(Native Method)  代码 public void getMusicToArray(){ /** * 此处目前存在报错 * */ ContentResolver contentResolver = getContentResolver(); Cursor cursor = contentResolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,null,null,null,MediaStore.Audio.Media.DEFAULT_SORT_ORDER); List<MusicListData> mListData = new ArrayList<>(); //Cursor是每行的集合 if(cursor.moveToFirst()){ for(int i = 0; i <cursor.getCount();i++) { MusicListData data = new MusicListData(); long id = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media._ID)); String title = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE)); String artist = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST)); long duration = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.DURATION)); long size = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.SIZE)); String url = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA)); String abum = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM)); long albulm_id = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID)); int ismusic = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.IS_MUSIC)); Log.d("MMMM",url); if (ismusic != 0 && duration / (500 * 60) >= 1) { Log.d("M","循环2"); musicPath[i] = url; data.setTitle(title); data.setUrl(url); data.setSonger(artist); mListData.add(data); } //往下移动一行 cursor.moveToNext(); } } //释放集合 cursor.close(); }

Answer 1

getContentResolver()需要context，试试getApplicationContext().getContentResolver()