我正在尝试制作一个AutoCompleteTextView女巫将从联系人列表中完成用户输入,我做了但它造成了很大的性能损失。
我尝试使用CursorLoader(https://developer.android.com/training/load-data-background/setup-loader.html)
该应用现已强行关闭:
07-30 05:02:45.034: E/AndroidRuntime(1396): FATAL EXCEPTION: main
07-30 05:02:45.034: E/AndroidRuntime(1396): java.lang.ClassCastException:
android.content.CursorLoader cannot be cast to android.database.Cursor
代码:
@Override
public Loader<Cursor> onCreateLoader(int loaderID, Bundle bundle)
{
/*
* Takes action based on the ID of the Loader that's being created
*/
switch (loaderID) {
case NAMES_LOADER:
// Returns a new CursorLoader
CursorLoader peopleCursor = new CursorLoader(
context, // Parent activity context
ContactsContract.Contacts.CONTENT_URI, // Table to query
null, // Projection to return
null, // No selection clause
null, // No selection arguments
null // Default sort order
);
while (((Cursor) peopleCursor).moveToNext()) {
contactName = ((Cursor) peopleCursor).getString(((Cursor) peopleCursor)
.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
contactId = ((Cursor) peopleCursor).getString(((Cursor) peopleCursor)
.getColumnIndex(ContactsContract.Contacts._ID));
hasPhone = ((Cursor) peopleCursor)
.getString(((Cursor) peopleCursor)
.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER));
}
case PHONES_LOADER:
if ((Integer.parseInt(hasPhone) > 0)){
CursorLoader phonesCursor = new CursorLoader(
context, // Parent activity context
ContactsContract.CommonDataKinds.Phone.CONTENT_URI, // Table to query
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = "+ contactId, // Projection to return
null, // No selection clause
null // No selection arguments
// Default sort order
);
while (((Cursor) phonesCursor).moveToNext()){
//store numbers and display a dialog letting the user select which.
String phoneNumber = ((Cursor) phonesCursor).getString(
((Cursor) phonesCursor).getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
Map<String, String> NamePhoneType = new ContactMap();
NamePhoneType.put("Name", contactName);
NamePhoneType.put("Phone", phoneNumber);
mPeopleList.add(NamePhoneType);
}
}
default:
// An invalid id was passed in
return null;
}
}
这是错误部分:
while (((Cursor) peopleCursor).moveToNext()) {
contactName = ((Cursor) peopleCursor).getString(((Cursor) peopleCursor)
.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
contactId = ((Cursor) peopleCursor).getString(((Cursor) peopleCursor)
.getColumnIndex(ContactsContract.Contacts._ID));
hasPhone = ((Cursor) peopleCursor)
.getString(((Cursor) peopleCursor)
.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER));
}
错误是因为我正在将Cursor转换为CursorLoader,我无法找到另一种方法,因为我需要的方法在CursorLoader类型中是不可用的。
有没有人有解决方案?或其他方式自动完成联系而不损害性能? 谢谢!
答案 0 :(得分:2)
由于没有其他人提供答案,让我建议在创建光标后在onLoaderFinish中填充数组。 Cursor Loader本质上是一个查询语句而不是结果,这就是你无法从CursorLoader转换为Cursor的原因。
答案 1 :(得分:1)
以下代码是我用AutoCompleteTextView
填充设备上所有电子邮件地址的代码。
它展示了如何使用LoaderCallbacks<Cursor>
接口方法,并基于SDK提供的模板LoginActivity(在Eclipse中:File ... New ... Android Activity ... Login)。
准备CursorLoader
:
/**
* Creates a new {@link CursorLoader} that reads email addresses from the device contact list.
*/
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle)
{
/* URI for the device profile contact only - not used in this activity */
@SuppressWarnings("unused")
Uri uriDeviceProfileContact =
Uri.withAppendedPath(ContactsContract.Profile.CONTENT_URI,
ContactsContract.Contacts.Data.CONTENT_DIRECTORY);
/* URI for all contacts on the device */
Uri uriAllContacts = ContactsContract.CommonDataKinds.Email.CONTENT_URI;
CursorLoader profileLoader =
new CursorLoader(this, uriAllContacts, ProfileQuery.PROJECTION,
ContactsContract.Contacts.Data.MIMETYPE + " = ?", new String[]
{ ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE },
ContactsContract.CommonDataKinds.Email.ADDRESS);
return profileLoader;
}
请注意,这只定义了应该加载的内容 - 它不会尝试填充任何数据结构。
处理结果:
/**
* Adds loaded email addresses to the autocomplete field.
*/
@Override
public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor)
{
List<String> emails = new ArrayList<String>();
cursor.moveToFirst();
while (!cursor.isAfterLast())
{
emails.add(cursor.getString(ProfileQuery.ADDRESS));
cursor.moveToNext();
}
addEmailsToAutoComplete(emails);
}
private void addEmailsToAutoComplete(List<String> emailAddressCollection)
{
// Create adapter to tell the AutoCompleteTextView what to show in its dropdown list.
ArrayAdapter<String> adapter =
new ArrayAdapter<String>(InterviewMethodTest.this,
android.R.layout.simple_dropdown_item_1line, emailAddressCollection);
myAutoCompleteField.setAdapter(adapter);
}
我没有使用onLoaderReset(Loader<Cursor>)
方法。
以上代码需要将以下数据投影到光标:
/**
* Defines the mappings used to get the email addresses from the contact list.
*/
private interface ProfileQuery
{
/** Columns to fetch from the database into the cursor. */
String[] PROJECTION =
{ ContactsContract.CommonDataKinds.Email.ADDRESS,
ContactsContract.CommonDataKinds.Email.IS_PRIMARY, };
/** Column in cursor of the address. */
int ADDRESS = 0;
/** Column in cursor of the primary email address indicator. */
@SuppressWarnings("unused")
int IS_PRIMARY = 1;
}