我正在使用Xamarin表单创建一个混合移动应用。我想显示所有电话簿联系人的列表,其中包含以下详细信息:
- 名称
- 图像
我在Android清单中添加了权限" read_contacts"。以下是获得所有联系人的代码:
var contactList = new List < MContacts > ();
var ContactDetailURI = ContactsContract.Contacts.ContentUri;
string[] ContactDetailProjection = {
ContactsContract.Contacts.InterfaceConsts.Id,
ContactsContract.Contacts.InterfaceConsts.DisplayName,
ContactsContract.ContactsColumns.ContactLastUpdatedTimestamp,
ContactsContract.Contacts.InterfaceConsts.PhotoId,
ContactsContract.Contacts.InterfaceConsts.PhotoUri,
ContactsContract.Contacts.InterfaceConsts.PhotoFileId,
ContactsContract.Contacts.InterfaceConsts.PhotoThumbnailUri
};
var ContactDetailCursor = Forms.Context.ContentResolver.Query(
ContactDetailURI,
ContactDetailProjection,
null,
null,
null
);
if (ContactDetailCursor.MoveToFirst()) {
do {
var contact = new MContacts();
contact.Id = ContactDetailCursor.GetLong(ContactDetailCursor.GetColumnIndex(ContactDetailProjection[0]));
contact.DisplayName = ContactDetailCursor.GetString(ContactDetailCursor.GetColumnIndex(ContactDetailProjection[1]));
contact.PhotoId = ContactDetailCursor.GetString(ContactDetailCursor.GetColumnIndex(ContactDetailProjection[6]));
contactList.Add(contact);
} while (ContactDetailCursor.MoveToNext());
}
return contactList;
我有一个XAML页面,该页面将显示数据。我正在使用图像单元格。以下是XAML代码:
<ContentPage.Content>
<ListView x:Name="ContactList">
<ListView.ItemTemplate>
<DataTemplate>
<ImageCell
Text="{Binding DisplayName}"
ImageSource="{Binding PhotoId}">
</ImageCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ContentPage.Content>
我获得了联系人名称,但是在图像字段中,我只得到:
content://com.android.contacts/contacts/1/photo
为了显示图像,该怎么办?我在这里缺少什么?
P.S。我不想使用Xamarin.mobile组件或任何其他组件。
Android通过内容提供商和内容解析器从其他应用程序访问文件。因此,您首先必须将该content://
方案URL转换为文件流。您可以这样做:
// convert uri to stream (Android code, ContentResolver is a property of the Activity class):
var stream = ContentResolver.OpenInputStream(uri);
// or when not in an activity (e.g. a service):
var otherStream = Android.App.Application.Context.ContentResolver.OpenInputStream(uri);
// eventually convert the stream to imagesource for consumption in Xamarin Forms:
var imagesource = Xamarin.Forms.ImageSource.FromStream(() => stream);
有关更多信息,请参见以下资源:
- https://developer.xamarin.com/guides/android/platform_features/intro_to_to_content_providers/
- https://developer.android.com/guide/topics/providers/content-providers.html