如果注释掉setCursorToStringConverter()方法,则可以看到基于此视图输入的文本显示一个可用选项列表。但由于未实现convertToString()方法,因此自定义Tokenizer的terminateToken()方法无法接收到我打算传递的字符串,而是代表光标对象的表示字符串,因为光标尚未用于获取结果查询中所需列的当前字符串值。
有人能够实现这三个类(CursorLoader/LoaderManger、MultiAutoCompleteTextView和Tokenizer)的组合吗?
我已经能够实现一个由SimpleCursorAdapter支持的自定义MultiAutoCompleteTextView以及自定义Tokenizer,但严格模式抱怨MultiAutoCompleteTextView中的光标未明确关闭。是否可能使用CursorLoader来实现这一点?任何帮助都将不胜感激。
public class CustomMultiAutoCompleteTextView extends MultiAutoCompleteTextView
implements LoaderManager.LoaderCallbacks<Cursor> {
private final String DEBUG_TAG = getClass().getSimpleName().toString();
private Messenger2 mContext;
private RecipientsCursorAdapter mAdapter;
private ContentResolver mContentResolver;
private final char delimiter = ' ';
private CustomMultiAutoCompleteTextView mView;
// If non-null, this is the current filter the user has provided.
private String mCurFilter;
// These are the Contacts rows that we will retrieve.
final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
ContactsContract.Contacts._ID,
ContactsContract.Contacts.DISPLAY_NAME };
public CustomMultiAutoCompleteTextView(Context c) {
super(c);
init(c);
}
public CustomMultiAutoCompleteTextView(Context c, AttributeSet attrs) {
super(c, attrs);
init(c);
}
private void init(Context context) {
mContext = (Messenger2) context;
mContentResolver = mContext.getContentResolver();
mView = this;
mAdapter = new RecipientsCursorAdapter(mContext, 0, null, new String[0], new int[0], mContext);
mAdapter.setCursorToStringConverter(new CursorToStringConverter() {
@Override
public CharSequence convertToString(Cursor c) {
String contactName = c.getString(c.getColumnIndexOrThrow(ContactsContract.Contacts.DISPLAY_NAME));
return contactName;
}
});
addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
Log.d(DEBUG_TAG, "onTextChanged()");
if (!s.equals(""))
mCurFilter = s.toString();
else
mCurFilter = "";
mContext.getLoaderManager().restartLoader(0, null, mView);
}
@Override
public void afterTextChanged(Editable s) {
}
});
setAdapter(mAdapter);
setTokenizer(new SpaceTokenizer());
mContext.getLoaderManager().initLoader(0, null, this);
}
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
// This is called when a new Loader needs to be created. This
// sample only has one Loader, so we don't care about the ID.
// First, pick the base URI to use depending on whether we are
// currently filtering.
Log.d(DEBUG_TAG, "onCreateLoader()");
Uri baseUri;
if (mCurFilter != null) {
baseUri = Uri.withAppendedPath( ContactsContract.Contacts.CONTENT_FILTER_URI,Uri.encode(mCurFilter));
} else {
baseUri = ContactsContract.Contacts.CONTENT_URI;
}
// Now create and return a CursorLoader that will take care of
// creating a Cursor for the data being displayed.
String selection = "((" + ContactsContract.Contacts.DISPLAY_NAME
+ " NOTNULL) AND ("
+ ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1) AND ("
+ ContactsContract.Contacts.DISPLAY_NAME + " != '' ))";
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME
+ " COLLATE LOCALIZED ASC";
return new CursorLoader(mContext, baseUri, CONTACTS_SUMMARY_PROJECTION,
selection, null, sortOrder);
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
// Swap the new cursor in. (The framework will take care of closing
// the old cursor once we return.)
Log.d(DEBUG_TAG, "onLoadFinished()");
mAdapter.swapCursor(data);
}
public void onLoaderReset(Loader<Cursor> loader) {
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
Log.d(DEBUG_TAG, "onLoaderReset()");
mAdapter.swapCursor(null);
}
private class SpaceTokenizer implements Tokenizer {
public int findTokenStart(CharSequence text, int cursor) {
int i = cursor;
while (i > 0 && text.charAt(i - 1) != delimiter) {
i--;
}
while (i < cursor && text.charAt(i) == delimiter) {
i++;
}
return i;
}
public int findTokenEnd(CharSequence text, int cursor) {
int i = cursor;
int len = text.length();
while (i < len) {
if (text.charAt(i) == delimiter) {
return i;
} else {
i++;
}
}
return len;
}
public CharSequence terminateToken(CharSequence text) {
Log.d(DEBUG_TAG, "terminateToken()");
int i = text.length();
while (i > 0 && text.charAt(i - 1) == delimiter) {
i--;
}
if (i > 0 && text.charAt(i - 1) == delimiter) {
return text;
} else {
CharSequence contactName = createContactBubble(text);
return contactName;
}
}
}
}
更新 1
我现在正在调用setStringConversionColumn()
方法,而不是像@Olaf建议的那样调用setCursorToStringConverter()
。 我已经在onLoadFinished()
中设置了这个,因为这是唯一的时间Cursor
可用,因为这实现了一个LoaderManger
。
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
// Swap the new cursor in. (The framework will take care of closing
// the old cursor once we return.)
Log.d(DEBUG_TAG, "onLoadFinished()");
mAdapter.setStringConversionColumn(data.getColumnIndexOrThrow(ContactsContract.Contacts.DISPLAY_NAME));
mAdapter.swapCursor(data);
}
这可以选择一个项目用于MultiAutoCompleteTextView
,但是不允许在MultiAutoCompleteTextView
中选择多个项目。
我猜测onTextChanged()
方法存在一些问题,因为它调用了restartLoader()
。对于此视图中的第一个条目有效,但对于后续条目无效。此时我不确定出了什么问题。
更新2
所以我已经识别出了问题。问题在于TextWatcher的onTextChanged()
方法。在完成第一个标记的选择(比方说该标记是“Joe Johnson”)之后,然后在此MultiAutoCompleteTextView
中输入更多字符(如al
),传递到onTextChanged()
方法中的参数s
的值现在包括不仅是新添加的字符,还包括已经被终止的标记中的字符(此时s
的值为Joe Johnson al
)。现在mCursor
的值设置为Joe Johnson al
,随后传递到onCreateLoader()
中的查询中,这显然不会返回任何结果。是否有任何解决这种情况的方法?我接受任何建议。
更新3
当我实现一个由SimpleCursorAdapter
支持的自定义MultiAutoCompleteTextView
以及自定义Tokenizer
时,我像这样设置了FilterQueryProvider
:
mAdapter.setFilterQueryProvider(new FilterQueryProvider() {
@Override
public Cursor runQuery(CharSequence constraint) {
Log.d(DEBUG_TAG, "runQuery() : constraint " + constraint);
Uri baseUri;
if (constraint != null) {
baseUri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_FILTER_URI,
Uri.encode(constraint.toString()));
} else {
baseUri = ContactsContract.Contacts.CONTENT_URI;
}
String selection = "((" + ContactsContract.Contacts.DISPLAY_NAME
+ " NOTNULL) AND ("
+ ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1) AND ("
+ ContactsContract.Contacts.DISPLAY_NAME + " != '' ))";
final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
ContactsContract.Contacts._ID,
ContactsContract.Contacts.DISPLAY_NAME};
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME
+ " COLLATE LOCALIZED ASC";
Cursor c = mContentResolver.query(baseUri,
CONTACTS_SUMMARY_PROJECTION, selection, null, sortOrder);
return c;
}
});
由于某种原因,runQuery()
方法会在 TextWatcher 的 onTextChanged()
方法中被调用两次:
public void onTextChanged(CharSequence s, int start, int before,
int count) {
Log.d(DEBUG_TAG, "onTextChanged() : s " + s);
mAdapter.getFilterQueryProvider().runQuery(s);
}
在我的先前示例中,第一次传递到
runQuery()
方法的constraint
变量是Joe Johnson al
。然后第二次调用runQuery()
方法时,constraint
变量的值为al
。我不知道为什么onTextChanged()
方法中只调用了一次runQuery()
方法,但它却运行了两次。
setStringConversionColumn()
而不是setCursorToStringConverter()
。 - Olaf Dietsche