有没有办法将返回的行数限制为游标? 我有一个有大约4000个联系人的电话,我只需要其中一些。
这是我正在使用的代码
db = new dBHelper(this);
ContentResolver cr = getContentResolver();
Cursor cursor;
cursor = cr.query(ContactsContract.Contacts.CONTENT_URI,null, null, null, ContactName + " ASC");
Log.i(TAG, CLASSNAME + " got contacts entries");
for (int it = 0; it <100 ; it++){//cursor.getCount()
Log.i(TAG, CLASSNAME + " getting string");
String mytimes_contacted = cursor.getString(cursor.getColumnIndex(dBHelper.times_contacted));
Log.i(TAG, CLASSNAME + " done from the string");
}
我得到的日志是
I/Check(11506): [ContactsPicker] got contacts entries
I/Check(11506): [ContactsPicker] getting first string
D/AndroidRuntime(11506): Shutting down VM
W/dalvikvm(11506): threadid=1: thread exiting with uncaught exception (group=0x2aac8578)
D/dalvikvm(11541): GC_CONCURRENT freed 923K, 46% free 4000K/7303K, external 1685K/2133K, paused 1ms+8ms
E/AndroidRuntime(11506): FATAL EXCEPTION: main
E/AndroidRuntime(11506): java.lang.RuntimeException: Unable to start activity ComponentInfo{~~my package name~~}: android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 3537
答案 0 :(得分:36)
要限制光标中的结果数量,请尝试:
cursor = cr.query(ContactsContract.Contacts.CONTENT_URI,null, null, null, ContactName + " LIMIT 100");
while(cursor.moveToNext()) {
// something clever
}
答案 1 :(得分:5)
已接受的答案对于android 11不再有效。在android 11中,添加了一个约束以不允许在排序值中使用LIMIT。您需要将查询与包参数一起使用。例如:
val bundle = Bundle().apply {
putInt(ContentResolver.QUERY_ARG_LIMIT, 100)
}
resolver.query(
ContactsContract.Contacts.CONTENT_URI,
projection,
bundle,
null
)
答案 2 :(得分:3)
从Android 11开始,上述解决方案将无法正常工作,您可以尝试使用此方法来获取数据。
/**
* Call to fetch all media on device, it but be called synchronously since function is called on a background thread
*/
private fun fetchGalleryImages(
context: Context,
offset: Int,
limit: Int
): List<MediaItem> {
val galleryImageUrls = mutableListOf<MediaItem>()
try {
if (EasyPermissions.hasPermissions(
context,
Manifest.permission.WRITE_EXTERNAL_STORAGE
)
) {
// Define the columns that will be fetched
val projection = arrayOf(
MediaStore.Files.FileColumns._ID,
MediaStore.Files.FileColumns.DATA,
MediaStore.Files.FileColumns.DATE_ADDED,
MediaStore.Files.FileColumns.MEDIA_TYPE,
MediaStore.Files.FileColumns.MIME_TYPE,
MediaStore.Files.FileColumns.TITLE,
MediaStore.Video.Media.DURATION
)
val selection =
"${MediaStore.Files.FileColumns.MEDIA_TYPE} = ? OR ${MediaStore.Files.FileColumns.MEDIA_TYPE} = ?"
val selectionArgs = arrayOf(
MediaStore.Files.FileColumns.MEDIA_TYPE_IMAGE.toString(),
MediaStore.Files.FileColumns.MEDIA_TYPE_VIDEO.toString()
)
/**
* Change the way to fetch Media Store
*/
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
// Get All data in Cursor by sorting in DESC order
context.contentResolver.query(
contentUri(),
projection,
Bundle().apply {
// Limit & Offset
putInt(ContentResolver.QUERY_ARG_LIMIT, limit)
putInt(ContentResolver.QUERY_ARG_OFFSET, offset)
// Sort function
putString(
ContentResolver.QUERY_ARG_SORT_COLUMNS,
MediaStore.Files.FileColumns.DATE_MODIFIED
)
putInt(
ContentResolver.QUERY_ARG_SORT_DIRECTION,
ContentResolver.QUERY_SORT_DIRECTION_DESCENDING
)
// Selection
putString(ContentResolver.QUERY_ARG_SQL_SELECTION, selection)
putStringArray(
ContentResolver.QUERY_ARG_SQL_SELECTION_ARGS,
selectionArgs
)
}, null
)
} else {
val sortOrder =
"${MediaStore.Files.FileColumns.DATE_MODIFIED} DESC LIMIT $limit OFFSET $offset"
// Get All data in Cursor by sorting in DESC order
context.contentResolver.query(
contentUri(),
projection,
selection,
selectionArgs,
sortOrder
)
}?.use { cursor ->
while (cursor.moveToNext()) {
galleryImageUrls.add(
MediaItem(
cursor.getLong(cursor.getColumnIndex(MediaStore.Files.FileColumns._ID)),
ContentUris.withAppendedId(
contentUri(),
cursor.getLong(cursor.getColumnIndex(MediaStore.Files.FileColumns._ID))
),
cursor.getString(cursor.getColumnIndex(MediaStore.Files.FileColumns.DATA)),
cursor.getStringOrNull(cursor.getColumnIndex(MediaStore.Files.FileColumns.MIME_TYPE)),
cursor.getLongOrNull(cursor.getColumnIndex(MediaStore.Video.Media.DURATION))
)
)
}
}
}
} catch (ex: Exception) {
ex.printStackTrace()
}
return galleryImageUrls
}
答案 3 :(得分:2)
在 android 26 查询方法升级。此函数正在使用这些参数。 uri uri, String[] 投影, Bundle queryArgs, CancellationSignal 取消信号
下面的例子我得到了最近的 5 张照片。
id13
答案 4 :(得分:1)
如果有人正在寻找上述 Ignacio Tomas Crespo 答案的 Java 版本,
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
cursor = context.getContentResolver().query(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI
.buildUpon()
.encodedQuery("limit=" + offSet + "," + "100")
.build(),
columns,
null,
null,
null);
} else {
Bundle bundle = new Bundle();
bundle.putInt(ContentResolver.QUERY_ARG_LIMIT, 100);
cursor = context.getContentResolver()
.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
columns,
bundle,
null);
}