本文介绍了ClassCastException异常不应该发生的的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

即时得到一个ClassCastException是不应该发生。
这里是code:

  TwitterApplication TA =(TwitterApplication)getApplication();
    OAuthProvider p值= ta.getProvider();

正如你看到我尝试从应用程序中投TwitterApplication。

 公共类TwitterApplication扩展应用{私人Twitter的微博;公共Twitter的getTwitter(){
    返回this.twitter;
}公共无效setTwitter(微博T){
    this.twitter = T;
}私人OAuthProvider供应商;
私人消费CommonsHttpOAuthConsumer;公共无效setProvider(OAuthProvider OAP){
    this.provider = OAP;
}公共OAuthProvider getProvider(){
    返回this.provider;
}公共无效setConsumer(CommonsHttpOAuthConsumer C){
    this.consumer = C;
}公共CommonsHttpOAuthConsumer getConsumer(){
    返回this.consumer;
}

正如你在这里看到,它扩展应用程序。

是我的铸造知识有缺陷?
为什么会出现这个错误?
谢谢

编辑:
全堆栈跟踪:

  15 03-03:45:09.275:ERROR / AndroidRuntime(3192):了java.lang.RuntimeException:无法启动活动ComponentInfo {com.laytproducts.IN/com.laytproducts。 IN.TwitterUpdate}:java.lang.ClassCastException:android.app.Application
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1696)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1716)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.ActivityThread.access $ 1500(ActivityThread.java:124)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:968)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.os.Handler.dispatchMessage(Handler.java:99)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.os.Looper.loop(Looper.java:130)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.ActivityThread.main(ActivityThread.java:3806)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在java.lang.reflect.Method.invokeNative(本机方法)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在java.lang.reflect.Method.invoke(Method.java:507)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:839)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在dalvik.system.NativeStart.main(本机方法)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):java.lang.ClassCastException:产生的原因android.app.Application
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在com.laytproducts.IN.TwitterUpdate.getConsumerProvider(TwitterUpdate.java:148)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在com.laytproducts.IN.TwitterUpdate.onCreate(TwitterUpdate.java:117)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1660)
03-03 15:45:09.275:ERROR / AndroidRuntime(3192):11 ...更多

清单:

 <使用许可权的android:NAME =android.permission.INTERNET对/>
<使用许可权的android:NAME =android.permission.GET_ACCOUNTS>< /使用许可权><应用机器人:图标=@绘制/图标机器人:标签=@字符串/ APP_NAME>
    <活动机器人:名字=。MainAct
              机器人:标签=@字符串/ APP_NAME>
        &所述;意图滤光器>
            <作用机器人:名字=android.intent.action.MAIN/>
            <类机器人:名字=android.intent.category.LAUNCHER/>
        &所述; /意图滤光器>
    < /活性GT;    <活动机器人:主NAME = />    <活动机器人:名字=。FBUpdate>
        &所述;意图滤光器>
            <作用机器人:名字=com.laytproducts.IN.WidgetAct.ACTION_WIDGET_FB/>
        &所述; /意图滤光器>
    < /活性GT;
    <活动机器人:名字=。TwitterUpdate>
        &所述;意图滤光器>
            <作用机器人:名字=com.laytproducts.IN.WidgetAct.ACTION_WIDGET_TWITTER/>
        &所述; /意图滤光器>
    < /活性GT;    <应用机器人:名字=TwitterApplication/>    <接收机器人:名字=。WidgetAct>
        &所述;意图滤光器>
            <作用机器人:名字=android.appwidget.action.APPWIDGET_UPDATE/>
        &所述; /意图滤光器>
        <元数据机器人:名字=android.appwidget.provider
            机器人:资源=@ XML / winfo/>
    < /接收器>
< /用途>


解决方案

您会得到一个错误,如果通过getApplication()返回的具体类实际上不是TwitterApplication对象。

您已经修改了你的Andr​​oid清单文件,以便它使用这个TwitterApplication类?如果没有,你需要做的。简单地扩展应用是不够的 - 你必须告诉Android的使用TwitterApplication具体类

Im getting a ClassCastException that shouldnt be happening.Here is the code:

TwitterApplication ta = (TwitterApplication)getApplication();
    OAuthProvider p = ta.getProvider();

As you see im trying to cast TwitterApplication from an Application.

public class TwitterApplication extends Application {

private Twitter twitter;

public Twitter getTwitter(){
    return this.twitter;
}

public void setTwitter(Twitter t){
    this.twitter = t;
}

private OAuthProvider provider;
private CommonsHttpOAuthConsumer consumer;

public void setProvider(OAuthProvider oap){
    this.provider = oap;
}

public OAuthProvider getProvider(){
    return this.provider;
}

public void setConsumer(CommonsHttpOAuthConsumer c){
    this.consumer = c;
}

public CommonsHttpOAuthConsumer getConsumer(){
    return this.consumer;
}

As you see here, it extends application.

Is my casting knowledge faulty?Why am I getting this error?Thanks

EDIT:Full Stacktrace:

03-03 15:45:09.275: ERROR/AndroidRuntime(3192): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.laytproducts.IN/com.laytproducts.IN.TwitterUpdate}: java.lang.ClassCastException: android.app.Application
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1696)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1716)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.ActivityThread.access$1500(ActivityThread.java:124)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:968)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.os.Looper.loop(Looper.java:130)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.ActivityThread.main(ActivityThread.java:3806)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at java.lang.reflect.Method.invokeNative(Native Method)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at java.lang.reflect.Method.invoke(Method.java:507)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at dalvik.system.NativeStart.main(Native Method)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192): Caused by: java.lang.ClassCastException: android.app.Application
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at com.laytproducts.IN.TwitterUpdate.getConsumerProvider(TwitterUpdate.java:148)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at com.laytproducts.IN.TwitterUpdate.onCreate(TwitterUpdate.java:117)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1660)
03-03 15:45:09.275: ERROR/AndroidRuntime(3192):     ... 11 more

Manifest:

 <uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.GET_ACCOUNTS"></uses-permission>

<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".MainAct"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <activity android:name=".Main" />

    <activity android:name=".FBUpdate">
        <intent-filter>
            <action android:name="com.laytproducts.IN.WidgetAct.ACTION_WIDGET_FB" />
        </intent-filter>
    </activity>
    <activity android:name=".TwitterUpdate">
        <intent-filter>
            <action android:name="com.laytproducts.IN.WidgetAct.ACTION_WIDGET_TWITTER" />
        </intent-filter>
    </activity>

    <application android:name="TwitterApplication" />

    <receiver android:name=".WidgetAct">
        <intent-filter>
            <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
        </intent-filter>
        <meta-data android:name="android.appwidget.provider"
            android:resource="@xml/winfo"/>
    </receiver>
</application>
解决方案

You will get an error if the concrete class returned by getApplication() is not actually a TwitterApplication object.

Have you amended your Android manifest file so that it uses this TwitterApplication class? If not, you will need to do. Simply extending Application is not enough - you must tell Android to use the TwitterApplication concrete class.

这篇关于ClassCastException异常不应该发生的的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

06-10 18:25