在Kotlin Fragment中访问View时出现NullPointerException:原因与解决方案
大家好!我是Kotlin和Android开发的新手。遇到了一个问题:在Fragment中尝试访问界面元素(TextView、Button)时,我得到了NullPointerException。这是我的代码:
```kotlin
class MyFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_my, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
// 这里尝试访问view
val textView = view.findViewById(R.id.my_text_view)
textView.text = "你好" // NPE!
}
}
```
但有时我使用kotlin-android-extensions并这样写:
```kotlin
import kotlinx.android.synthetic.main.fragment_my.*
class MyFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedI