Java android:从strings.xml填充微调器
我在用一周中的天数填充微调器时遇到问题 布局xml:Java android:从strings.xml填充微调器,java,android,Java,Android,我在用一周中的天数填充微调器时遇到问题 布局xml: <Spinner android:id="@+id/week_spinner" android:layout_width="match_parent" android:layout_height="wrap_content" android:drawSelectorOnTop="true"/> 昨天这个工作很好。我不知道我是否改变了什么,或者我是否有日食问题 super.onCreate(sav
<Spinner
android:id="@+id/week_spinner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:drawSelectorOnTop="true"/>
昨天这个工作很好。我不知道我是否改变了什么,或者我是否有日食问题
super.onCreate(savedInstanceState);
setContentView(yourView);
day = (Spinner)findViewById(R.id.week_spinner);
在从xml获取微调器之前,您忘记设置视图。如果不设置视图,findviewbyd
返回null
对
null
引用的任何操作都会导致NullPointerException
Nambari解释了接收NullPointerException的原因以及如何正确使用findViewById()
我想指出一种更简单的方法来设置使用默认设置的微调器,只需将其添加到XML中:
android:entries="@array/days_of_week"
您可以在
onCreate()
中删除我对适配器的所有引用,因为这是正确的,我只是展示了另一种方法。flip IDK为什么我没有想到这一点。布莱利安特!!
11-05 21:24:31.235: W/dalvikvm(867): threadid=1: thread exiting with uncaught exception (group=0x40a9a228)
11-05 21:24:31.245: E/AndroidRuntime(867): FATAL EXCEPTION: main
11-05 21:24:31.245: E/AndroidRuntime(867): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.cathal.timetable/com.cathal.timetable.AddModule}: java.lang.NullPointerException
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2202)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2237)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.ActivityThread.access$600(ActivityThread.java:139)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1262)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.os.Handler.dispatchMessage(Handler.java:99)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.os.Looper.loop(Looper.java:154)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.ActivityThread.main(ActivityThread.java:4974)
11-05 21:24:31.245: E/AndroidRuntime(867): at java.lang.reflect.Method.invokeNative(Native Method)
11-05 21:24:31.245: E/AndroidRuntime(867): at java.lang.reflect.Method.invoke(Method.java:511)
11-05 21:24:31.245: E/AndroidRuntime(867): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
11-05 21:24:31.245: E/AndroidRuntime(867): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
11-05 21:24:31.245: E/AndroidRuntime(867): at dalvik.system.NativeStart.main(Native Method) 11-05 21:24:31.245: E/AndroidRuntime(867): Caused by: java.lang.NullPointerException 11-05 21:24:31.245: E/AndroidRuntime(867): at com.cathal.timetable.AddModule.onCreate(AddModule.java:18)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.Activity.performCreate(Activity.java:4538)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
11-05 21:24:31.245: E/AndroidRuntime(867): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2158)
11-05 21:24:31.245: E/AndroidRuntime(867): ... 11 more
super.onCreate(savedInstanceState);
setContentView(yourView);
day = (Spinner)findViewById(R.id.week_spinner);
android:entries="@array/days_of_week"