Android Studio编译中“png-cruncher_*”异常的解决方案

最近写的几个小demo在编译时总是出现错误，打印的log如下：
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Exception in thread “png-cruncher_21” java.lang.RuntimeException: Timed out while waiting for slave aapt process, make sure the aapt execute at D:\Android-SDK\Android\android-sdk\build-tools\23.0.0\aapt.exe can run successfully (some anti-virus may block it) or try setting environment variable SLAVE_AAPT_TIMEOUT to a value bigger than 5 seconds
at com.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)
at com.android.builder.png.QueuedCruncher1.creation(QueuedCruncher.java:110)atcom.android.builder.tasks.WorkQueue.run(WorkQueue.java:203)atjava.lang.Thread.run(Thread.java:745)Exceptioninthread“png−cruncher40”java.lang.RuntimeException:Timedoutwhilewaitingforslaveaaptprocess,makesuretheaaptexecuteatD:\Android−SDK\Android\android−sdk\build−tools\23.0.0\aapt.execanrunsuccessfully(someanti−virusmayblockit)ortrysettingenvironmentvariableSLAVEAAPTTIMEOUTtoavaluebiggerthan5secondsatcom.android.builder.png.AaptProcess.waitForReady(AaptProcess.java:108)atcom.android.builder.png.QueuedCruncher1.creation(QueuedCruncher.java:110)
at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:203)
at java.lang.Thread.run(Thread.java:745)
……
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Error:Error: Could not create the Java Virtual Machine.
Error:Error: A fatal exception has occurred. Program will exit.
Error:Error: Could not create the Java Virtual Machine.
Error:Error: A fatal exception has occurred. Program will exit.
Error:Execution failed for task ‘:app:transformClassesWithDexForDebug’.
com.android.build.api.transform.TransformException: java.lang.RuntimeException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process ‘command ‘C:\Program Files\Java\jdk1.7.0_79\bin\java.exe” finished with non-zero exit value 1

从log上看，说SLAVE_AAPT_TIMEOUT 的值大于5，于是增加系统变量并设置为30，再次编译还是有如上的错误，汗-_-!
继续搜索解决方法，网上说这可能与build tools有关，需要更新一下build tools。
更新build tools 重新编译，错误没了，OK搞定。

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参考链接：
http://stackoverflow.com/questions/30111443/android-studio-fails-to-build-new-project-timed-out-while-wating-for-slave-aapt

http://www.maiziedu.com/article/11351/