我在xamarin.forms工作。我陷入了Android的活动导航。
我的整个申请工作都是Activity MainActivity。
在我的一个内容页面中，我想打开包含所有联系人列表的联系人应用程序。
我创建了另一个活动，并使用依赖关系服务（如下面的代码）从内容页面开始按钮点击活动。
var intent = new Intent(Forms.Context, typeof(ContactApplicationActivity));
Forms.Context.StartActivity(intent);
OnCreate的{{1}}方法我转到联系人应用程序。当用户点击任何联系ContactApplicationActivity方法调用并打开邮件和电子邮件默认应用程序时。
ContactApplicationActivity.cs：
OnActivityResult一切都很好。但问题是从public class ContactApplicationActivity : Activity
{
public object smsTask { get; private set; }
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
var contactPickerIntent = new Intent(Intent.ActionPick,
Android.Provider.ContactsContract.Contacts.ContentUri);
StartActivityForResult(contactPickerIntent, 101);
}
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
if (InviteFriends.IsSMS && !InviteFriends.IsEmail)
{
if (requestCode == 101 && resultCode == Result.Ok)
{
//Ensure we have data returned
if (data == null || data.Data == null)
return;
var addressBook = new Xamarin.Contacts.AddressBook(this);
addressBook.PreferContactAggregation = false;
//Load the contact via the android contact id in the last segment of the Uri returned by the android contact picker
var contact = addressBook.Load(data.Data.LastPathSegment);
//Use linq to find a mobile number
var mobile = (from p in contact.Phones
where p.Type == Xamarin.Contacts.PhoneType.Mobile
select p.Number).FirstOrDefault();
//See if the contact has a mobile number
if (string.IsNullOrEmpty(mobile))
{
Toast.MakeText(this, "No Mobile Number for contact!",
ToastLength.Short).Show();
return;
}
else
{
if (CrossMessaging.Current.SmsMessenger.CanSendSms)
{
CrossMessaging.Current.SmsMessenger.SendSms(mobile, "My Message");
}
}
}
}
else if (!InviteFriends.IsSMS && InviteFriends.IsEmail)
{
//Ensure we have data returned
if (data == null || data.Data == null)
return;
var addressBook = new Xamarin.Contacts.AddressBook(this);
addressBook.PreferContactAggregation = false;
//Load the contact via the android contact id in the last segment of the Uri returned by the android contact picker
var contact = addressBook.Load(data.Data.LastPathSegment);
//Use linq to find a mobile number
var emailid = (from p in contact.Emails
where p.Type == Xamarin.Contacts.EmailType.Home
select p.Address).FirstOrDefault();
//See if the contact has a mobile number
if (string.IsNullOrEmpty(emailid))
{
Toast.MakeText(this, "No Email for contact!",
ToastLength.Short).Show();
return;
}
else
{
var email = BuildSampleEmail(emailid, true).Build();
if (CrossMessaging.Current.EmailMessenger.CanSendEmail)
{
CrossMessaging.Current.EmailMessenger.SendEmail(email);
}
}
}
}
public static EmailMessageBuilder BuildSampleEmail(string ToEmailId, bool sendAsHtml = false)
{
//var builder = new EmailMessageBuilder()
// .To(ToEmailId)
// .Cc("cc.plugins@xamarin.com")
// .Bcc(new[] { "bcc1.plugins@xamarin.com", "bcc2.plugins@xamarin.com" })
// .Subject("eRecall App");
var builder = new EmailMessageBuilder()
.To(ToEmailId)
.Subject("ABC");
if (sendAsHtml)
builder.BodyAsHtml("<b>My Message </b>");
return builder;
}
}
活动打开联系人应用程序。 ContactApplicationActivity在后台。当我尝试从后台模式打开我的原始应用程序时。它打开时带有标题MainActivity的空白屏幕。当我按下后退按钮ContactApplicationActivity时，我的上一个内容页面已打开。
我想打开MainActivity的最后一个内容页面，没有任何空白屏幕
是否可以使用MainActivity解决问题？