当应用程序同步时，我试图更新数据库中每一行中的“html”列。我在此处使用本教程将应用程序添加到“配置文件”列表中。这是我在 SyncAdapter 中使用的代码：
private static void performSync(Context context, Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult) throws OperationCanceledException {
MySQLiteHelper openHelperClass;
SQLiteDatabase sqliteDatabase;
String str;
mContentResolver = context.getContentResolver();
Log.i(TAG, "performSync: " + account.toString());
Log.v(TAG, "CDS Opened!");
openHelperClass = new MySQLiteHelper(context);
sqliteDatabase = openHelperClass.getWritableDatabase();
Log.v(TAG, "CDS loaded db!");
Cursor cursor = sqliteDatabase.query("offline", null, null, null, null, null, null);
Log.v(TAG, "CDS queried!");
if(cursor != null) {
Log.v(TAG, "Cursor not null!");
Log.v(TAG,cursor.toString());
if(cursor.moveToFirst()) {
Log.v(TAG, "first pos");
while(cursor.moveToNext()) {
Log.v(TAG, "1");
Log.v(TAG, "Cursor moving!");
String skolelogg = cursor.getString(cursor.getColumnIndexOrThrow(MySQLiteHelper.COLUMN_SKOLE_LOGGING_OFFLINE));
int skplid = cursor.getInt(cursor.getColumnIndexOrThrow(MySQLiteHelper.COLUMN_PLAN_ID));
String skplant = cursor.getString(cursor.getColumnIndexOrThrow(MySQLiteHelper.COLUMN_PLAN_TYPE));
int offid = cursor.getInt(cursor.getColumnIndexOrThrow(MySQLiteHelper.COLUMN_ID_OFFLINE));
try {
HttpClient hc = new DefaultHttpClient();
HttpPost post = new HttpPost("https://romres.ist-asp.com/WebUntis/Timetable.do?simple=1&type=" + skplant + "&" + skolelogg + "&id="+ Integer.toString(skplid));
HttpResponse rp = hc.execute(post);
if(rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
str = EntityUtils.toString(rp.getEntity());
Log.v(TAG, "Syncing....");
Log.v(TAG, "Syncing ID: " + Integer.toString(offid));
String csstext = "<link rel='stylesheet' type='text/css' href='Styles/webuntis.css'>";
csstext += "<style type='text/css'>";
csstext += "*.A_0_1 {background:#f49f25;font-size:12px;}";
csstext += "*.I_100_28 {background:#ffff80;}";
csstext += "*.I_100_29 {background:#ffff80;}";
csstext += "*.I_100_30 {background:#ffff80;}";
csstext += "*.I_100_31 {background:#ffff80;}";
csstext += "*.I_100_368 {background:#ffff80;}";
csstext += "*.I_100_710 {background:#ff00ff;}";
csstext += "*.A_0_9 td,*.A_0_11 td,*.A_0_12 td,*.A_11_9 td,*.A_11_11 td,*.A_11_12 td,*.A_40_9 td,*.A_40_11 td,*.A_40_12 td,*.A_41_9 td,*.A_41_11 td,*.A_41_12 td,*.A_5_9 td,*.A_5_11 td,*.A_5_12 td,*.A_10_9 td,*.A_10_11 td,*.A_10_12 td,*.A_50_9 td,*.A_50_11 td,*.A_50_12 td,*.A_51_9 td,*.A_51_11 td,*.A_51_12 td,*.A_15_9 td,*.A_15_11 td,*.A_15_12 td,*.A_20_9 td,*.A_20_11 td,*.A_20_12 td {text-decoration: line-through;}";
csstext += "</style>";
Document doc = Jsoup.parse(str);
Element title = doc.select("div.def").first();
String s = title.toString();
Element offlinetext = doc.append("<div class='offlinetext'>Offline-Timeplan</div>");
String offltt = "<div class='offlinetext'>Offline-Timeplan</div>";
String extraCSS = "<style>";
extraCSS += ".offlinetext {font-family: Arial; font-size: 20px; font-style: normal; font-weight: 500; color: #FF9900; line-height: 19px; height: 30px;}';";
extraCSS += "</style>";
Element title2 = doc.select("div.pagetitle").first();
String s2 = title2.toString();
str = csstext + extraCSS + offltt + s2 + s;
ContentValues cv = new ContentValues();
cv.put(MySQLiteHelper.COLUMN_SKOLE_HTML_CODE, str);
sqliteDatabase.update(MySQLiteHelper.TABLE_OFFLINE, cv, "_id = ?", new String [] { Integer.toString(offid) });
}
}
catch(IOException e){
Log.v(TAG, e.toString());
}
}
}
else {
Log.v(TAG, "moveToNext() is false");
}
}
else{
Log.v(TAG, "It's null");
}
}
这是我在 Android 的设置菜单中按“同步”时的 LogCat 输出：
12-04 21:17:30.066: D/webviewglue(20944): nativeDestroy view: 0x51028af0 12-04 21:17:39.241: I/ContactsSyncAdapterService(21115): performSync: Account {name=*, type=*.account} 12-04 21:17:39.246: V/ContactsSyncAdapterService(21115): CDS Opened! 12-04 21:17:39.251: V/ContactsSyncAdapterService(21115): CDS loaded db! 12-04 21:17:39.251: V/ContactsSyncAdapterService(21115): CDS queried! 12-04 21:17:39.251: V/ContactsSyncAdapterService(21115): Cursor not null! 12-04 21:17:39.256: V/ContactsSyncAdapterService(21115): android.database.sqlite.SQLiteCursor@411c4de0 12-04 21:17:39.256: V/ContactsSyncAdapterService(21115): moveToNext() is false
问题是在到达 cursor.moveToFirst() 之前一切正常。如您所见，游标同时为 null 且不为 null(?)，因为它通过了“cursor != null”检查但返回 null 的“cursor.moveToFirst”。我真的需要帮助。我不知道出了什么问题。我仍然是编写 SyncAdapter 甚至是 ContentProvider 的菜鸟。
编辑：我很愚蠢。正如贾斯汀指出的那样，游标确实是空的，因为表中没有行。在我在表格中添加一个条目后它起作用了！