如何从应用程序小部件访问 sqlite 数据库？

Question

DBHelper 是创建数据库的数据库助手class。它有一个方法 getTimetable，returns 一个 Timetable 对象。当我在主要 activity 中使用它时它工作正常并且 returns 正确的时间表对象。我在创建 DBhelper 时将 (this) 作为上下文参数传入。但是，当我尝试在小部件 updateAppWidget 方法中运行它时，它使系统崩溃，我认为碰巧我没有传递与主 activity.

相同的上下文

static void updateAppWidget(Context context, AppWidgetManager appWidgetManager, int appWidgetId) {

    String daysFull[] = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};

    DBHelper myDB = new DBHelper(context);
    Timetable t = myDB.getTimetable();
    //t.getTimeSlot(daysFull[Calendar.DAY_OF_WEEK],(new Date()).getHours()+":00")
    TimeSlot ts = null;
    String text = "";
    System.out.print(t.toString());
    if (t != null) {

        int hourCount = (new Date()).getHours();
        while (hourCount < 22) {

            if (t.getTimeSlot(daysFull[Calendar.DAY_OF_WEEK], hourCount + ":00") != null) {

                ts = t.getTimeSlot(daysFull[Calendar.DAY_OF_WEEK], (new Date()).getHours() + ":00");
                break;
            }
        hourCount++;
    }
    System.out.println("hello hello hello");
    if (ts != null) {

        text = ts.getStartTime() + "\n" + ts.getModule() + "\n" + ts.getRoomNumber();
    } else {

        text = "No More Classes\nFor Today";
    }
}

Answer 1

今天是星期天，所以我从 Calendar.DAY_OF_WEEK 中得到 7，所以当调用 daysFull[Calendar.DAY_OF_WEEK] 时，它指向不存在的变量并崩溃...

所以我改用了 daysFull[Calendar.DAY_OF_WEEK]-1...

Answer 2

AppWidget和你的应用有不同的context，你可以使用ContentProvider

http://developer.android.com/reference/android/content/ContentProvider.html

A content provider is only required if you need to share data between multiple applications

如何从应用程序小部件访问 sqlite 数据库？

How to access sqlite database from app widget?

sqlite

android

widget