spinner如果再次選擇項目

Question

我在我的軟件包中創建了一個名爲NoDefaultSpinner的類文件。但是，當我嘗試在我的Android應用程序中使用它時，我收到了一個會使程序崩潰的異常。

我複製了由Dimitar Vukman和Blundell從this link提供的代碼，然後更新此代碼，因爲Alex Miragall指示了一些帖子（因爲現在我正在爲Android 4.0創建應用程序）。我刪除了Dimitar的onClick方法，並在課程結束時粘貼了Alex的代碼。

然後我編輯我的活動與紡紗，我改變

static Spinner spinner1; 

到

static NoDefaultSpinner spinner1; 

和

variables.spinner1 = (Spinner) findViewById(R.id.spinner1); 

到

variables.spinner1 = (NoDefaultSpinner) findViewById(R.id.spinner1); 

我也試圖改變

<Spinner 
     android:id="@+id/spinner1" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:text="@string/place" /> 

到

<NoDefaultSpinner 
     android:id="@+id/spinner1" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:text="@string/place" /> 

的問題：我做錯了什麼，爲什麼我的應用程序崩潰，我能做些什麼，以使其正常工作？

這些都是錯誤，如果我不更新佈局：

01-08 01:50:48.835: E/AndroidRuntime(13362): FATAL EXCEPTION: main 
01-08 01:50:48.835: E/AndroidRuntime(13362): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.life/com.example.life.search_activity}: java.lang.ClassCastException: android.widget.Spinner cannot be cast to com.example.life.NoDefaultSpinner 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.ActivityThread.access$600(ActivityThread.java:141) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.os.Looper.loop(Looper.java:137) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.ActivityThread.main(ActivityThread.java:5039) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at java.lang.reflect.Method.invokeNative(Native Method) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at java.lang.reflect.Method.invoke(Method.java:511) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at dalvik.system.NativeStart.main(Native Method) 
01-08 01:50:48.835: E/AndroidRuntime(13362): Caused by: java.lang.ClassCastException: android.widget.Spinner cannot be cast to com.example.life.NoDefaultSpinner 
01-08 01:50:48.835: E/AndroidRuntime(13362): at com.example.life.search_activity.onCreate(search_activity.java:181) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.Activity.performCreate(Activity.java:5104) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
01-08 01:50:48.835: E/AndroidRuntime(13362): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
01-08 01:50:48.835: E/AndroidRuntime(13362): ... 11 more 

這些都是錯誤的，如果我做更新

01-08 01:53:22.803: E/AndroidRuntime(13417): FATAL EXCEPTION: main 
01-08 01:53:22.803: E/AndroidRuntime(13417): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.life/com.example.life.search_activity}: android.view.InflateException: Binary XML file line #7: Error inflating class NoDefaultSpinner 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.ActivityThread.access$600(ActivityThread.java:141) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.os.Looper.loop(Looper.java:137) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.ActivityThread.main(ActivityThread.java:5039) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at java.lang.reflect.Method.invokeNative(Native Method) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at java.lang.reflect.Method.invoke(Method.java:511) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at dalvik.system.NativeStart.main(Native Method) 
01-08 01:53:22.803: E/AndroidRuntime(13417): Caused by: android.view.InflateException: Binary XML file line #7: Error inflating class NoDefaultSpinner 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:698) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.rInflate(LayoutInflater.java:746) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.inflate(LayoutInflater.java:489) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.inflate(LayoutInflater.java:396) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.inflate(LayoutInflater.java:352) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:270) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.Activity.setContentView(Activity.java:1881) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at com.example.life.search_activity.onCreate(search_activity.java:177) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.Activity.performCreate(Activity.java:5104) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
01-08 01:53:22.803: E/AndroidRuntime(13417): ... 11 more 
01-08 01:53:22.803: E/AndroidRuntime(13417): Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.NoDefaultSpinner" on path: /data/app/com.example.life-1.apk 
01-08 01:53:22.803: E/AndroidRuntime(13417): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at java.lang.ClassLoader.loadClass(ClassLoader.java:501) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at java.lang.ClassLoader.loadClass(ClassLoader.java:461) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.createView(LayoutInflater.java:552) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:643) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:66) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:660) 
01-08 01:53:22.803: E/AndroidRuntime(13417): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:685) 
01-08 01:53:22.803: E/AndroidRuntime(13417): ... 21 more 

我發現兩種解決方案的佈局（其他城市微調至NoDefaultSpinner）我的問題在這裏堆：

The first

The second

我有同樣的問題，有人問這些問題。這個問題很好地呈現在那裏。

我嘗試了所有的解決方案，但每次我嘗試使用這些特殊的spinners應用程序崩潰時啓動一項活動。也許我確實使用了錯誤的類？

Answer 1

你的第一個例外是

java.lang.ClassNotFoundException: Didn't find class "android.view.NoDefaultSpinner" on path: /data/app/com.example.life-1.apk 

引起因此，在你的XML佈局中使用完全限定域名（com.myPackage.NoDefaultSpinner）。否則，Android會認爲這個類是它自己的包的一部分，它顯然會失敗。

而且，這樣的：

ClassCastException: android.widget.Spinner cannot be cast to com.example.life.NoDefaultSpinner 

表明NoDefaultSpinner不延長Spinner，確保它是。