getInstrumentation（）。getTargetContext（）返回的上下文为什么不同于getActivity（）。getApplicationContext（）？

Question

getInstrumentation（）。getTargetContext（）返回一个类型的android.app.Context。但我有一种感觉，它是android.app.ApplicationContext的基类，因为我在下面的日志中获得了类转换异常。

而且

getActivity（）。getApplicationContext（）返回一个类型android.app.Context，虽然它真的返回基类由我实现ActivityInstrumentationTestCase2的定义我的活动。

的logcat：

04-04 21:02:27.036: INFO/TestRunner(431): started: testIt(edu.rockies.rockies.activity.courses.test.TopicTest) 
04-04 21:02:27.126: INFO/TestRunner(431): failed: testIt(edu.rockies.rockies.activity.courses.test.TopicTest) 
04-04 21:02:27.126: INFO/TestRunner(431): ----- begin exception ----- 
04-04 21:02:27.136: INFO/TestRunner(431): java.lang.ClassCastException: android.app.ApplicationContext 
04-04 21:02:27.136: INFO/TestRunner(431):  at edu.rockies.rockies.activity.courses.test.TopicTest.setUp(TopicTest.java:27) 
04-04 21:02:27.136: INFO/TestRunner(431):  at junit.framework.TestCase.runBare(TestCase.java:125) 
04-04 21:02:27.136: INFO/TestRunner(431):  at junit.framework.TestResult$1.protect(TestResult.java:106) 
04-04 21:02:27.136: INFO/TestRunner(431):  at junit.framework.TestResult.runProtected(TestResult.java:124) 
04-04 21:02:27.136: INFO/TestRunner(431):  at junit.framework.TestResult.run(TestResult.java:109) 
04-04 21:02:27.136: INFO/TestRunner(431):  at junit.framework.TestCase.run(TestCase.java:118) 
04-04 21:02:27.136: INFO/TestRunner(431):  at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:169) 
04-04 21:02:27.136: INFO/TestRunner(431):  at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:154) 
04-04 21:02:27.136: INFO/TestRunner(431):  at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:430) 
04-04 21:02:27.136: INFO/TestRunner(431):  at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1447) 
04-04 21:02:27.136: INFO/TestRunner(431): ----- end exception ----- 
04-04 21:02:27.156: INFO/TestRunner(431): finished: testIt(edu.rockies.rockies.activity.courses.test.TopicTest) 

Link

Answer 1

See Question.我想我解决我自己的问题。