Android 如何在Kotlin中初始化片段中的意图？

我得到一个空指针异常

日志：

2020-07-05 10:42:52.821 20008-20008/com.riddhi.nfine E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.riddhi.nfine, PID: 20008
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.riddhi.nfine/com.riddhi.nfine.Income.AddBankFragment}: kotlin.KotlinNullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2843)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:193)
    at android.app.ActivityThread.main(ActivityThread.java:6669)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
 Caused by: kotlin.KotlinNullPointerException
    at com.riddhi.nfine.Income.AddBankFragment.<init>(AddBankFragment.kt:195)
    at java.lang.Class.newInstance(Native Method)
    at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69)
    at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45)
    at android.app.Instrumentation.newActivity(Instrumentation.java:1215)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2831)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048) 
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808) 
    at android.os.Handler.dispatchMessage(Handler.java:106) 
    at android.os.Looper.loop(Looper.java:193) 
    at android.app.ActivityThread.main(ActivityThread.java:6669) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

---

}

在附加片段之前，您不能调用

getActivity

（即

val intent=activity！！.intent！！

）中的

activity

），即在

onatach（Context）

、

onCreate（）

或之后的任何方法中。因此，您可以将意图设置为

lateinit var

，并在

onCreate（）方法中初始化它：

private lateinit var intent: Intent

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    intent = activity!!.intent!!
}

请注意，如果您使用
activity（）
而不是
活动，您将得到一条更具描述性的错误消息，该消息将确切地告诉您它为null的原因（片段尚未附加）

private lateinit var intent: Intent

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    intent = activity!!.intent!!
}