如果我尝试启动服务，为什么会得到InstantiationException？
可能重复：
Android RuntimeException：无法实例化服务
我一直试图解决以下问题整天，但似乎没有任何工作。
我有一个小部件，通过IntentService获取视图更新。 但是，当我试图启动这个服务时，我不断收到一个InstantiationException。 下面是错误的堆栈跟踪和我用来启动服务的代码。 我不相信我需要发布服务的代码，因为它从来没有开始，但如果有人认为否则我当然会这样做。
堆栈跟踪
05-30 13:58:47.150: ERROR/AndroidRuntime(1163): FATAL EXCEPTION: main 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): java.lang.RuntimeException: Unable to instantiate service syrligt.cashtrack.widgets.StatisticsWidgetUpdateService: java.lang.InstantiationException: syrligt.cashtrack.widgets.StatisticsWidgetUpdateService 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.app.ActivityThread.handleCreateService(ActivityThread.java:1904) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.app.ActivityThread.access$2500(ActivityThread.java:117) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:982) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.os.Handler.dispatchMessage(Handler.java:99) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.os.Looper.loop(Looper.java:123) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.app.ActivityThread.main(ActivityThread.java:3647) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at java.lang.reflect.Method.invokeNative(Native Method) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at java.lang.reflect.Method.invoke(Method.java:507) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at dalvik.system.NativeStart.main(Native Method) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): Caused by: java.lang.InstantiationException: syrligt.cashtrack.widgets.StatisticsWidgetUpdateService 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at java.lang.Class.newInstanceImpl(Native Method) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at java.lang.Class.newInstance(Class.java:1409) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): at android.app.ActivityThread.handleCreateService(ActivityThread.java:1901) 05-30 13:58:47.150: ERROR/AndroidRuntime(1163): ... 10 more 小工具代码
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { for(int i = 0; i<appWidgetIds.length ; i++){ Intent intent = new Intent(context,StatisticsWidgetUpdateService.class); intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]); context.startService(intent); } }
服务代码
public class StatisticsWidgetUpdateService extends IntentService { public StatisticsWidgetUpdateService(String name) { super(name); } @Override protected void onHandleIntent(Intent intent) { AppWidgetManager appWidgetManager=AppWidgetManager.getInstance(this); int appWidgetId = intent.getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID); CashDB cdb = new CashDB(this); cdb.open(); RemoteViews updatedViews = new RemoteViews(getPackageName(), R.layout.statistics_widget); updatedViews.removeAllViews(R.id.list); PendingIntent pendingIntent = null; Cursor c = null; Intent i = null; SharedPreferences sp = getSharedPreferences(Preferences.PREFERENCES, 0); double incomeAmount = cdb.sumTransactions(null, new TimeFrame(sp.getInt(Preferences.DEFAULT_TIME_FRAME, TimeFrame.ALL_TIME)), 1); double expenseAmount = Math.abs(cdb.sumTransactions(null, new TimeFrame(sp.getInt(Preferences.DEFAULT_TIME_FRAME, TimeFrame.ALL_TIME)), -1)); int value = StatisticsWidgetConfig.getConfig(this, appWidgetId); c = cdb.fetchCategoriesWithSums(new TimeFrame(sp.getInt(Preferences.DEFAULT_TIME_FRAME, TimeFrame.ALL_TIME)), value, 3); updatedViews.setTextViewText(R.id.balance, StringConversion.formatAmount(incomeAmount - expenseAmount));//balance text updatedViews.setViewVisibility(R.id.value_bar, incomeAmount - expenseAmount < 0 ? R.drawable.list_item_value_red_medium : R.drawable.list_item_value_green_medium);//value bar updatedViews.setTextViewText(R.id.income, StringConversion.formatAmount(incomeAmount));//income text updatedViews.setTextViewText(R.id.expense, StringConversion.formatAmount(expenseAmount));//expense text updatedViews.setTextViewText(R.id.popularity, Integer.toString(cdb.fetchAllTransactions(new TimeFrame(sp.getInt(Preferences.DEFAULT_TIME_FRAME, TimeFrame.ALL_TIME)), null, null,null).getCount()));//popularity text for(int j = 0; j<c.getCount();j++){ c.moveToPosition(j); RemoteViews statisticsView = new RemoteViews(getPackageName(), R.layout.statistics_widget_list); statisticsView.setTextViewText(R.id.name, c.getString(c.getColumnIndexOrThrow(CashDB.CATEGORY_NAME)));//category name statisticsView.setImageViewResource(R.id.icon, c.getInt(c.getColumnIndexOrThrow(CashDB.CATEGORY_IMAGE)));//category icon statisticsView.setViewVisibility(R.id.starred, c.getInt(c.getColumnIndexOrThrow(CashDB.CATEGORY_STARRED)) == 1 ? View.VISIBLE : View.GONE);//starred icon double procent = c.getLong(c.getColumnIndexOrThrow(CashDB.TRANSACTION_SUM)); procent = procent/(value == -1 ? expenseAmount : incomeAmount); procent = Math.abs(procent * 100); if((procent%1) < 0.1){ statisticsView.setTextViewText( R.id.procent, String.format("%.0f%s",procent," %"));//procentage }else{ statisticsView.setTextViewText( R.id.procent, String.format("%.1f%s",procent," %"));//procentage } Bitmap bmp; if(value == -1){ bmp=BitmapFactory.decodeResource(getResources(), R.drawable.progress_bar_red); }else{ bmp=BitmapFactory.decodeResource(getResources(), R.drawable.progress_bar_green); } int width=(int) (procent*4.056); // kankse fuckar upp på andra display storlekar if(width<2){ width=2; } width = (int) getResources().getDisplayMetrics().density * width; int height=10; Bitmap resizedbitmap=Bitmap.createScaledBitmap(bmp, width, height, true); statisticsView.setImageViewBitmap(R.id.progress_bar, resizedbitmap);//procent bar i = new Intent(this, ViewCategory.class); i.putExtra(CashDB.CATEGORY_ID, c.getLong(c.getColumnIndexOrThrow(CashDB.CATEGORY_ID))); i.setAction("cashtrackViewCategory"+c.getLong(c.getColumnIndexOrThrow(CashDB.CATEGORY_ID))); pendingIntent = PendingIntent.getActivity(this, 0, i, PendingIntent.FLAG_UPDATE_CURRENT); statisticsView.setOnClickPendingIntent(R.id.statistics_widget_list_layout, pendingIntent); updatedViews.addView(R.id.list, statisticsView); } c.close(); cdb.close(); appWidgetManager.updateAppWidget(appWidgetId, updatedViews); }
}
你的服务需要有一个公有的无参数构造函数。 Otherwize，Android将不能实例化它。
所以replace
public StatisticsWidgetUpdateService(String name) { super(name); }
同
public StatisticsWidgetUpdateService() { super("SOME NAME"); }
你有没有在AndroidManifest.xml中声明服务名称？
<service android:name="YOUR_SERVICE_NAME" />
