[Android] Encountered when creating a project problem

Android support library I installed the ADT20 After you create a project , the last prompt support library require 8,
check some information that the extras \ Android \ create a support folder and file folder capabilities to support file copy
folder, I was doing, but to re- create a project that I was v4, click on the install / upgrade updated , always update fails,
how to solve it , or Which man has support library 8 and later sent to me , thank the
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open SDK Manager which will have support library options got to put this on the installation
- previous versions do not have this requirement ...
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under the Extras "Android Support Library" of
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I open the SDK manager only shows already installed package in Extras below Android Capabilitiey, but no Android Support Library, has been following the progress of the load
Fetching URL: https://dl-ssl.google.com/android/repository/repository-7.xml, like the address, but in the end failed to load , has not shown the package is not installed , I do not know how to solve , please enlighten heroes ah , So now will not
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problem has been resolved, as you say , do not know why it does not work the morning , but fortunately resolved
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me to install the Android ; Support Library but it is 7 or reported the same mistake, that it will be 8 , the same update failed
who give points !
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very troubled by this problem after installation extras \ Android has support folder which also has content. entire sdk have checked that there are no capabilities, install / upgrade and check again button does not respond . Replace all things are like this too , do not know what the reason .
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master who has : Android Support Library, revision 18, upload to me, thank you ! E-mail : 530993362@qq.com,