Kotlin 中的意图

Question

所以，我知道在Java中我们用它来启动新的 Activity

 Intent intent = new Intent(this, SomeActivity.class);
startActivity(intent);

但是我正在使用 Kotlin 编写一个项目，所以在 Kotlin 中就像

val intent = Intent(this,SomeActivity::class.java)
startActivity(intent)

但它因问题而崩溃

FATAL EXCEPTION: main
Process: com.pashabred.passlin, PID: 15243
                                                                           java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pashabred.passlin/com.pashabred.passlin.Enterring}: kotlin.KotlinNullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
    at android.app.ActivityThread.access$800(ActivityThread.java:151)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5254)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
                                                                            Caused by: kotlin.KotlinNullPointerException
    at com.pashabred.passlin.Enterring.onCreate(Enterring.kt:17)
    at android.app.Activity.performCreate(Activity.java:5990)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
    at android.app.ActivityThread.access$800(ActivityThread.java:151)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5254)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

原文由 Pavel Bredelev 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

确保您有（ 问号）：

 override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
}

反而：

 override fun onCreate(savedInstanceState: Bundle) {
    super.onCreate(savedInstanceState)
}

原文由 klimat 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

如果问题仍然存在或其他“Stack Overflowers”遇到类似情况，请确保您的 Activity 文件名（即 SomeActivity）在“AndroidManifest.xml”文件中相应命名或相同

原文由 Uram Mnisi 发布，翻译遵循 CC BY-SA 4.0 许可协议