Android：獲取最近打開app列表

按下任務物理鍵，會顯示最近打開的App列表，能夠用來切換多任務，如何經過代碼來實現這種效果呢？
相似下面這樣：

利用反射便可實現這個功能，示例代碼以下：

private void showRecentApps() {
        Class serviceManagerClass;
        try {
            serviceManagerClass = Class.forName("android.os.ServiceManager");
            Method getService = serviceManagerClass.getMethod("getService",
                    String.class);
            IBinder retbinder = (IBinder) getService.invoke(
                    serviceManagerClass, "statusbar");
            Class statusBarClass = Class.forName(retbinder
                    .getInterfaceDescriptor());

            Object statusBarObject = statusBarClass.getClasses()[0].getMethod(
                    "asInterface", IBinder.class).invoke(null,
                    new Object[] { retbinder });
            Method clearAll = statusBarClass.getMethod("toggleRecentApps");
            clearAll.setAccessible(true);
            clearAll.invoke(statusBarObject);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }