java - 在运行时在微调器中添加项目

Question

如何在运行时在微调器中添加值？

我正在使用一个微调器，我想在其中添加另一个类列表中的项目。我正在使用以下代码，但它给了我空指针异常。

ArrayAdapter<Address> adapter = new ArrayAdapter<Address>(
    this,
    android.R.layout.simple_spinner_item,
    HomePage.NearPlaces
);
adapter.setDropDownViewResource(
    android.R.layout.simple_spinner_dropdown_item
);
Place.setAdapter(adapter);

LogCat 输出:

INFO/ActivityManager(96): Starting: Intent { cmp=com.emx.OnDaMove/.SpotMe } from pid 20881
WARN/ActivityManager(96): Activity pause timeout for HistoryRecord{40705eb0 com.emx.OnDaMove/.HomePage}
DEBUG/AndroidRuntime(20881): Shutting down VM
WARN/dalvikvm(20881): threadid=1: thread exiting with uncaught exception (group=0x40015560)
ERROR/AndroidRuntime(20881): FATAL EXCEPTION: main
ERROR/AndroidRuntime(20881): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.emx.OnDaMove/com.emx.OnDaMove.SpotMe}: java.lang.NullPointerException
ERROR/AndroidRuntime(20881):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
ERROR/AndroidRuntime(20881):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
ERROR/AndroidRuntime(20881):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
ERROR/AndroidRuntime(20881):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
ERROR/AndroidRuntime(20881):     at android.os.Handler.dispatchMessage(Handler.java:99)
ERROR/AndroidRuntime(20881):     at android.os.Looper.loop(Looper.java:130)
ERROR/AndroidRuntime(20881):     at android.app.ActivityThread.main(ActivityThread.java:3683)
ERROR/AndroidRuntime(20881):     at java.lang.reflect.Method.invokeNative(Native Method)
ERROR/AndroidRuntime(20881):     at java.lang.reflect.Method.invoke(Method.java:507)
ERROR/AndroidRuntime(20881):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
ERROR/AndroidRuntime(20881):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
ERROR/AndroidRuntime(20881):     at dalvik.system.NativeStart.main(Native Method)
ERROR/AndroidRuntime(20881): Caused by: java.lang.NullPointerException
ERROR/AndroidRuntime(20881):     at com.emx.OnDaMove.SpotMe.onCreate(SpotMe.java:42)
ERROR/AndroidRuntime(20881):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
ERROR/AndroidRuntime(20881):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
ERROR/AndroidRuntime(20881):     ... 11 more

Answer 1

什么是 HomePage.NearPlaces？？？那应该是你的对象数组。这是怎么定义的。在我看来，您正在对应该是非静态对象的对象进行静态引用。如何定义传递到数组适配器实例化的对象数组将使您的微调器在运行时动态化。