我的项目编译和执行良好的调试模式，但是当我尝试生成一个签名的apk，错误出现。这将显示在消息日志中：

:app:proguardRelease

Warning:android.support.v4.app.DialogFragment: can't find referenced class android.support.v4.app.DialogFragment$DialogStyle

Warning:android.support.v4.app.FragmentTransaction: can't find referenced class android.support.v4.app.FragmentTransaction$Transit

Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$ResolvedLayoutDirectionMode

Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$LayoutDirectionMode

Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$LayerType

Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$AccessibilityLiveRegion

Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$ImportantForAccessibility

Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$OverScroll

Warning:android.support.v4.widget.DrawerLayout: can't find referenced class android.support.v4.widget.DrawerLayout$EdgeGravity

Warning:android.support.v4.widget.DrawerLayout: can't find referenced class android.support.v4.widget.DrawerLayout$LockMode

Warning:android.support.v4.widget.DrawerLayout: can't find referenced class android.support.v4.widget.DrawerLayout$State

Warning:there were 11 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)

Exception while processing task

java.io.IOException: Please correct the above warnings first.

at proguard.Initializer.execute(Initializer.java:473)

at proguard.ProGuard.initialize(ProGuard.java:233)

at proguard.ProGuard.execute(ProGuard.java:98)

at proguard.gradle.ProGuardTask.proguard(ProGuardTask.java:1074)

at com.android.build.gradle.tasks.AndroidProGuardTask.doMinification(AndroidProGuardTask.java:139)

at com.android.build.gradle.tasks.AndroidProGuardTask$1.run(AndroidProGuardTask.java:115)

at com.android.builder.tasks.Job.runTask(Job.java:48)

at com.android.build.gradle.tasks.SimpleWorkQueue$EmptyThreadContext.runTask(SimpleWorkQueue.java:41)

at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:227)

at java.lang.Thread.run(Thread.java:745)

:app:dexRelease UP-TO-DATE

:app:crashlyticsStoreDeobsRelease

:app:crashlyticsUploadDeobsRelease

:app:validateExternalOverrideSigning

:app:packageRelease FAILED

Error:Execution failed for task ':app:packageRelease'.

> Unable to compute hash of /home/kombo/RAL/Mpasho/app/build/intermediates/classes-proguard/release/classes.jar

我已经尝试过各种可能的方法来弥补这一点，通过更新我的构建工具，使用最新的gradle版本，检查所有的依赖项，错误仍然出现。

我很确定v4支持库存在于项目中，因为在调试模式中没有出现错误。