database - 如何让每个列表视图项显示不同的数据？

Question

我正在创建一个应用程序来组织学校课程并为每个班级输入作业。单击列表视图中的课程时，应显示该特定课程分配的另一个布局。我将如何保存每门课程的作业，以便在选择另一门课程时，使用如下数据库显示特定课程作业？

提前致谢。

public class CourseTable {

    // Database table
    public static final String TABLE_COURSE = "course";
    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_NAMECOURSE = "namecourse";
    public static final String COLUMN_DAYOFCOURSE = "dayofcourse";
    public static final String COLUMN_TIMEOFCOURSE = "timeofcourse";


    // Database creation SQL statement
    private static final String DATABASE_CREATE = "create table " 
                + TABLE_COURSE
                + "(" 
                + COLUMN_ID + " integer primary key autoincrement, " 
                + COLUMN_NAMECOURSE + " text not null, " 
                + COLUMN_DAYOFCOURSE + " text not null," 
                + COLUMN_TIMEOFCOURSE + " text not null,"
                + ");";

    public static void onCreate(SQLiteDatabase database) {
        database.execSQL(DATABASE_CREATE);
    }

    public static void onUpgrade(SQLiteDatabase database, int oldVersion,
            int newVersion) {
        Log.w(CourseTable.class.getName(), "Upgrading database from version "
                + oldVersion + " to " + newVersion
                + ", which will destroy all old data");
        database.execSQL("DROP TABLE IF EXISTS " + TABLE_COURSE);
        onCreate(database);
    }

内容提供商：

public class CourseContentProvider extends ContentProvider {

    // database
    private CourseDBHelper database;

    // Used for the UriMacher
    private static final int COURSES = 10;
    private static final int COURSE_ID = 20;

    private static final String AUTHORITY = "entcproject.organizer.tamu.main.contentprovider";

    private static final String BASE_PATH = "courses";
    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY
            + "/" + BASE_PATH);

    public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE
            + "/courses";
    public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE
            + "/course";

    private static final UriMatcher sURIMatcher = new UriMatcher(
            UriMatcher.NO_MATCH);
    static {
        sURIMatcher.addURI(AUTHORITY, BASE_PATH, COURSES);
        sURIMatcher.addURI(AUTHORITY, BASE_PATH + "/#", COURSE_ID);
    }

    @Override
    public boolean onCreate() {
        database = new CourseDBHelper(getContext());
        return false;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {

        SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();

        checkColumns(projection);

        queryBuilder.setTables(CourseTable.TABLE_COURSE);

        int uriType = sURIMatcher.match(uri);
        switch (uriType) {
        case COURSES:
            break;
        case COURSE_ID:
            queryBuilder.appendWhere(CourseTable.COLUMN_ID + "="
                    + uri.getLastPathSegment());
            break;
        default:
            throw new IllegalArgumentException("Unknown URI: " + uri);
        }

        SQLiteDatabase db2 = database.getWritableDatabase();
        Cursor cursor = queryBuilder.query(db2, projection, selection,
                selectionArgs, null, null, sortOrder);
        cursor.setNotificationUri(getContext().getContentResolver(), uri);

        return cursor;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        int uriType = sURIMatcher.match(uri);
        SQLiteDatabase sqlDB = database.getWritableDatabase();
        int rowsDeleted = 0;
        long id = 0;
        switch (uriType) {
        case COURSES:
            id = sqlDB.insert(CourseTable.TABLE_COURSE, null, values);
            break;
        default:
            throw new IllegalArgumentException("Unknown URI: " + uri);
        }
        getContext().getContentResolver().notifyChange(uri, null);
        return Uri.parse(BASE_PATH + "/" + id);
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
            String[] selectionArgs) {

        int uriType = sURIMatcher.match(uri);
        SQLiteDatabase sqlDB = database.getWritableDatabase();
        int rowsUpdated = 0;
        switch (uriType) {
        case COURSES:
            rowsUpdated = sqlDB.update(CourseTable.TABLE_COURSE, 
                    values, 
                    selection,
                    selectionArgs);
            break;
        case COURSE_ID:
            String id = uri.getLastPathSegment();
            if (TextUtils.isEmpty(selection)) {
                rowsUpdated = sqlDB.update(CourseTable.TABLE_COURSE, 
                        values,
                        CourseTable.COLUMN_ID + "=" + id, 
                        null);
            } else {
                rowsUpdated = sqlDB.update(CourseTable.TABLE_COURSE, 
                        values,
                        CourseTable.COLUMN_ID + "=" + id 
                        + " and " 
                        + selection,
                        selectionArgs);
            }
            break;
        default:
            throw new IllegalArgumentException("Unknown URI: " + uri);
        }
        getContext().getContentResolver().notifyChange(uri, null);
        return rowsUpdated;
    }

    private void checkColumns(String[] projection) {
        String[] available = { CourseTable.COLUMN_NAMECOURSE,
                CourseTable.COLUMN_DAYOFCOURSE, CourseTable.COLUMN_TIMEOFCOURSE,
                CourseTable.COLUMN_ID };
        if (projection != null) {
            HashSet<String> requestedColumns = new HashSet<String>(
                    Arrays.asList(projection));
            HashSet<String> availableColumns = new HashSet<String>(
                    Arrays.asList(available));
            // Check if all columns which are requested are available
            if (!availableColumns.containsAll(requestedColumns)) {
                throw new IllegalArgumentException(
                        "Unknown columns in projection");
            }
        }
    }

}