应用程序上Admob的Java.io.IOException错误

我会在我的应用程序中添加admob广告，我做的一切都是正确的，但当我尝试导出.apk时：

Error:Execution failed for task ':app:proguardRelease'.
> java.io.IOException: Please correct the above warnings first.

我的“proguard项目”是：

有什么帮助吗？ 是我第一次在这个博客上写，我希望我没有任何错误

编辑： 还有两个警告

    :app:proguardRelease
Warning:com.google.android.gms.internal.zzac: can't find referenced class android.net.http.AndroidHttpClient
Warning:com.google.android.gms.internal.zzw: can't find referenced method 'void addHeader(java.lang.String,java.lang.String)' in program class com.google.android.gms.internal.zzw$zza
Warning:com.google.android.gms.internal.zzw$zza: can't find referenced method 'void setURI(java.net.URI)' in program class com.google.android.gms.internal.zzw$zza
Warning:there were 2 unresolved references to classes or interfaces.
         You may need to add missing library jars or update their versions.
         If your code works fine without the missing classes, you can suppress
         the warnings with '-dontwarn' options.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedclass)
Warning:there were 2 unresolved references to program class members.
         Your input classes appear to be inconsistent.
         You may need to recompile the code.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedprogramclassmember)
:app:proguardRelease FAILED
Error:Execution failed for task ':app:proguardRelease'.
> java.io.IOException: Please correct the above warnings first.

---

是否有任何“以上警告”？是的，请查看第一篇帖子：）

    :app:proguardRelease
Warning:com.google.android.gms.internal.zzac: can't find referenced class android.net.http.AndroidHttpClient
Warning:com.google.android.gms.internal.zzw: can't find referenced method 'void addHeader(java.lang.String,java.lang.String)' in program class com.google.android.gms.internal.zzw$zza
Warning:com.google.android.gms.internal.zzw$zza: can't find referenced method 'void setURI(java.net.URI)' in program class com.google.android.gms.internal.zzw$zza
Warning:there were 2 unresolved references to classes or interfaces.
         You may need to add missing library jars or update their versions.
         If your code works fine without the missing classes, you can suppress
         the warnings with '-dontwarn' options.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedclass)
Warning:there were 2 unresolved references to program class members.
         Your input classes appear to be inconsistent.
         You may need to recompile the code.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedprogramclassmember)
:app:proguardRelease FAILED
Error:Execution failed for task ':app:proguardRelease'.
> java.io.IOException: Please correct the above warnings first.