如何在iOS 7下使用蓝牙键盘支持向上和向下箭头键

Under iOS 6, up and down arrow keys were respected by UITextView when using an external Bluetooth keyboard and when working in the simulator. Under iOS 7 the up and down arrow keys no longer do anything, although the left and right arrow keys still move the cursor.Under iOS 6, up and down arrow keys were respec