Android不同系统版本依然能调用到正确的API方法Demo——Service调用startForeground举例

private static final Class<?>[] mSetForegroundSignature = new Class[] {    boolean.class};private static final Class<?>[] mStartForegroundSignature = new Class[] {    int.class, Notification.class};private static final Class<?>[] mStopForegroundSignature = new Class[] {    boolean.class};private NotificationManager mNM;private Method mSetForeground;private Method mStartForeground;private Method mStopForeground;private Object[] mSetForegroundArgs = new Object[1];private Object[] mStartForegroundArgs = new Object[2];private Object[] mStopForegroundArgs = new Object[1];void invokeMethod(Method method, Object[] args) {    try {        method.invoke(this, args);    } catch (InvocationTargetException e) {        // Should not happen.        Log.w("ApiDemos", "Unable to invoke method", e);    } catch (IllegalAccessException e) {        // Should not happen.        Log.w("ApiDemos", "Unable to invoke method", e);    }}/** * This is a wrapper around the new startForeground method, using the older * APIs if it is not available. */void startForegroundCompat(int id, Notification notification) {    // If we have the new startForeground API, then use it.    if (mStartForeground != null) {        mStartForegroundArgs[0] = Integer.valueOf(id);        mStartForegroundArgs[1] = notification;        invokeMethod(mStartForeground, mStartForegroundArgs);        return;    }    // Fall back on the old API.    mSetForegroundArgs[0] = Boolean.TRUE;    invokeMethod(mSetForeground, mSetForegroundArgs);    mNM.notify(id, notification);}/** * This is a wrapper around the new stopForeground method, using the older * APIs if it is not available. */void stopForegroundCompat(int id) {    // If we have the new stopForeground API, then use it.    if (mStopForeground != null) {        mStopForegroundArgs[0] = Boolean.TRUE;        invokeMethod(mStopForeground, mStopForegroundArgs);        return;    }    // Fall back on the old API.  Note to cancel BEFORE changing the    // foreground state, since we could be killed at that point.    mNM.cancel(id);    mSetForegroundArgs[0] = Boolean.FALSE;    invokeMethod(mSetForeground, mSetForegroundArgs);}@Overridepublic void onCreate() {    mNM = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);    try {        mStartForeground = getClass().getMethod("startForeground",                mStartForegroundSignature);        mStopForeground = getClass().getMethod("stopForeground",                mStopForegroundSignature);        return;    } catch (NoSuchMethodException e) {        // Running on an older platform.        mStartForeground = mStopForeground = null;    }    try {        mSetForeground = getClass().getMethod("setForeground",                mSetForegroundSignature);    } catch (NoSuchMethodException e) {        throw new IllegalStateException(                "OS doesn't have Service.startForeground OR Service.setForeground!");    }}@Overridepublic void onDestroy() {    // Make sure our notification is gone.    stopForegroundCompat(R.string.foreground_service_started);}

摘自：http://developer.android.com/reference/android/app/Service.html#startForeground(int, android.app.Notification)