java.lang.NoClassDefFoundError: android.os.AsyncTask

Question

Android 2.2设备出现奇怪错误。以下工作在所有设备，我们从未遇到过这个错误，直到最近在GT-I5510 .我们的应用程序支持最小sdk级别8 .清除应用程序的数据设置和启动应用程序修复了这个问题，但我不明白为什么它不能找到类.Android支持库被添加。

    java.lang.NoClassDefFoundError: android.os.AsyncTask
        at com.example.android.library.stTest.stController.runTests(stController.java:228)
        at com.example.android.myapp.Fragments.Connection.ConnectionFragment$1.run(ConnectionFragment.java:69)
        at android.os.Handler.handleCallback(Handler.java:587)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:123)
        at android.app.ActivityThread.main(ActivityThread.java:4628)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:521)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
        at dalvik.system.NativeStart.

        //stController.java line is this
            pTest = new Test(context, this);
//does an async task
            pTest.execute(pTestData);



    public class Test extends AbstractTest<TestData, Void, TestData> {
        private static final String LOG_TAG = Debug.LOG_TAG_+"Test";
        private TestListener callback;  // Invoking object that implements the callback listeners
        /**
         * Constructor
         * @param context
         * @param callback  - the object that implements TestListener for the results.
         */
        public Test(final Context context, final TestListener callback) {
            super(context);
    //      Debug.v(LOG_TAG, "Constructor called.");
            this.callback = callback;
        }   

        @Override
        protected TestData doInBackground(final TestData... args) {
            TestData TestData = args[0];    
            if (!isTestPossible()) {
                TestData.setTestState(TestState.FAILED_TO_RUN);
            } else {
                TestData.setLocalIpAddress(Utils.getLocalIpAddress());
                try {
                    TestData.setTestState(TestState.RUNNING);
                    runTest(TestData);
                    TestData.setTestState(TestState.FINISHED);
                } catch (Exception e) {
                    Debug.e(LOG_TAG, "doInBackground(): runTest() exception: " + e);
                    TestData.setTestState(TestState.FAILED_TO_RUN);
                }
            }
            return TestData;
        }

        @Override
        protected void onPostExecute(TestData results) {
            if (callback == null) {
                Debug.e(LOG_TAG, "onPostExecute(): listener callback is null!!");
            } else {
                Debug.v(LOG_TAG, "onPostExecute() called. Results: " + results.toString());
                callback.onTestComplete(results);
                callback = null;            // Release reference to listener
            }
        }   
        @Override
        protected void onCancelled(TestData results) {
            if (callback == null) {
                Debug.e(LOG_TAG, "onCancelled(results): listener callback is null!!");
            } else {
                callback.onTestCancelled(results);
                callback = null;            // Release reference to listener
            }
        }
        // This version is also needed for older OS.
        @Override
        protected void onCancelled() {
            if (callback == null) {
                Debug.e(LOG_TAG, "onCancelled(): listener callback is null!!");
            } else {
                Debug.v(LOG_TAG, "onCancelled() called.");
                callback.onTestCancelled(null);
                callback = null;            // Release reference to listener
            }
        }

        // C++ functions.
        // This function runs the actual test.
        private native void runTest(TestData TestData);
    } 

    //Abstract Test
    public class AbstractTest <T1, T2, T3> extends AsyncTask<T1, T2, T3> {

        protected TelephonyManager    teleMan;
        protected ConnectivityManager connMan;
        private Context testContext;
        public AbstractTest(final Context context) {
            teleMan = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);
            connMan = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
            testContext=context;
        }

        protected boolean isTestPossible() {
            if (!Utils.isNetworkAvailable(testContext))
            {
                return false;
            }
            String localIpAddress = Utils.getLocalIpAddress();
            if (localIpAddress == null || localIpAddress == "") {
                Debug.w(LOG_TAG, "isTestPossible(): no local IP address!!");
                return false;       
            }
            return true;
        }
        @Override
        protected T3 doInBackground(T1... params) {
            return null;
        }
    }

Answer 1

将此写入onCreate()

中的应用程序类中

try {
  Class.forName("android.os.AsyncTask");
}
catch(Throwable ignore) {
  // ignored
}