TimeUnit中的致命异常

Question

我在Android 2.2和API level 8的模拟器上运行我的应用程序。

我在我的代码中测试了以下两行：

 long diffInDays = TimeUnit.MILLISECONDS.toDays(diffInMs); // API Level 9
 long diffInDays = TimeUnit.DAYS.convert(diffInMs,TimeUnit.MILLISECONDS); // API Level 1

我使用上面的代码行将以毫秒为单位的时间转换为以天为单位的时间，但得到了以下异常。为什么？

09-05 06:34:43.183: W/dalvikvm(12995): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-05 06:34:43.222: E/AndroidRuntime(12995): FATAL EXCEPTION: main
09-05 06:34:43.222: E/AndroidRuntime(12995): java.lang.NoSuchFieldError: java.util.concurrent.TimeUnit.DAYS
09-05 06:34:43.222: E/AndroidRuntime(12995):    at org.mabna.order.businessLayer.db.BoSaleDocuments.getEntAcc002Collection(BoSaleDocuments.java:161)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at org.mabna.order.ui.ActReportAcc002.onCreate(ActReportAcc002.java:178)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.os.Handler.dispatchMessage(Handler.java:99)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.os.Looper.loop(Looper.java:123)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at android.app.ActivityThread.main(ActivityThread.java:4627)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at java.lang.reflect.Method.invokeNative(Native Method)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at java.lang.reflect.Method.invoke(Method.java:521)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-05 06:34:43.222: E/AndroidRuntime(12995):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

toDays(long duration)需要API级别9。

请参阅http://developer.android.com/reference/java/util/concurrent/TimeUnit.html