title: Ionic Android build: java.lang.IllegalStateException: buildToolsVersion is not specified
body: <p>Since today, somehow my ionic project is not longer able to build for some reason. I already tried to remove the platform and add it again, but it didn't work. I now almost spent three ours with upgrading, downgrading and reinstalling cordova and ionic but for some reason I always get the following error when I try to build the Android version:  </p>
  
  <pre><code>Failed to notify ProjectEvaluationListener.afterEvaluate(), but primary configuration failure takes precedence.
      java.lang.IllegalStateException: buildToolsVersion is not specified.
              at com.google.common.base.Preconditions.checkState(Preconditions.java:176)
              at com.android.build.gradle.BasePlugin.createAndroidTasks(BasePlugin.java:599)
              at com.android.build.gradle.BasePlugin$10$1.call(BasePlugin.java:566)
              at com.android.build.gradle.BasePlugin$10$1.call(BasePlugin.java:563)
              at com.android.builder.profile.ThreadRecorder$1.record(ThreadRecorder.java:55)
              at com.android.builder.profile.ThreadRecorder$1.record(ThreadRecorder.java:47)
              at com.android.build.gradle.BasePlugin$10.execute(BasePlugin.java:562)
              at com.android.build.gradle.BasePlugin$10.execute(BasePlugin.java:559)
              at org.gradle.listener.BroadcastDispatch$ActionInvocationHandler.dispatch(BroadcastDispatch.java:109)
              at org.gradle.listener.BroadcastDispatch$ActionInvocationHandler.dispatch(BroadcastDispatch.java:98)
              at org.gradle.listener.BroadcastDispatch.dispatch(BroadcastDispatch.java:83)
              at org.gradle.listener.BroadcastDispatch.dispatch(BroadcastDispatch.java:31)
              at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
              at com.sun.proxy.$Proxy12.afterEvaluate(Unknown Source)
              at org.gradle.configuration.project.LifecycleProjectEvaluator.notifyAfterEvaluate(LifecycleProjectEvaluator.java:79)
              at org.gradle.configuration.project.LifecycleProjectEvaluator.evaluate(LifecycleProjectEvaluator.java:65)
              at org.gradle.api.internal.project.AbstractProject.evaluate(AbstractProject.java:504)
              at org.gradle.api.internal.project.AbstractProject.evaluate(AbstractProject.java:83)
              at org.gradle.execution.TaskPathProjectEvaluator.configureHierarchy(TaskPathProjectEvaluator.java:42)
              at org.gradle.configuration.DefaultBuildConfigurer.configure(DefaultBuildConfigurer.java:35)
              at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:129)
              at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:106)
              at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:86)
              at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:80)
              at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:33)
              at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:24)
              at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:36)
              at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:26)
              at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:47)
              at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:35)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:24)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.StartStopIfBuildAndStop.execute(StartStopIfBuildAndStop.java:33)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:71)
              at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:69)
              at org.gradle.util.Swapper.swap(Swapper.java:38)
              at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:69)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:60)
              at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:70)
              at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.DaemonHygieneAction.execute(DaemonHygieneAction.java:39)
              at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:119)
              at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:46)
              at org.gradle.launcher.daemon.server.DaemonStateCoordinator$1.run(DaemonStateCoordinator.java:246)
              at org.gradle.internal.concurrent.DefaultExecutorFactory$StoppableExecutorImpl$1.run(DefaultExecutorFactory.java:64)
              at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
              at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
              at java.lang.Thread.run(Thread.java:745)
  
      FAILURE: Build failed with an exception.
  </code></pre>
  
  <p>I already tried to set the buildToolsVersion in the config.xml but without any success. Did anyone have the same problem before?</p>