Question

我正在使用带有操作栏选项卡的viewpager，我在布局中有两个片段，问题是我得到 class-cast-exception

我的xml文件如下所示

 <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="horizontal" >

        <android.support.v4.view.ViewPager
            android:id="@+id/pager"
            android:layout_width="0px"
            android:layout_height="match_parent"
            android:layout_weight="2.5" />

        <FrameLayout
            android:id="@+id/fragment_details"
            android:layout_width="0px"
            android:layout_height="match_parent"
            android:layout_weight="2" />
    </LinearLayout>

我的活动歌曲和专辑中有两个标签。

它在纵向模式下正确加载，但在横向模式下，它显示了类强制转换异常。

12-08 04:30:08.198: E/AndroidRuntime(2166): FATAL EXCEPTION: main
12-08 04:30:08.198: E/AndroidRuntime(2166): java.lang.ClassCastException: com.nix.music.activity.fragments.SongDetailsFragment
12-08 04:30:08.198: E/AndroidRuntime(2166):     at com.nix.music.activity.fragments.AlbumFragMent.showDetails(AlbumFragMent.java:81)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at com.nix.music.activity.fragments.AlbumFragMent.access$0(AlbumFragMent.java:77)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at com.nix.music.activity.fragments.AlbumFragMent$1.onItemClick(AlbumFragMent.java:52)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at android.widget.AdapterView.performItemClick(AdapterView.java:284)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:1696)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at android.os.Handler.handleCallback(Handler.java:587)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at android.os.Handler.dispatchMessage(Handler.java:92)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at android.os.Looper.loop(Looper.java:123)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at android.app.ActivityThread.main(ActivityThread.java:4627)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at java.lang.reflect.Method.invokeNative(Native Method)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at java.lang.reflect.Method.invoke(Method.java:521)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
12-08 04:30:08.198: E/AndroidRuntime(2166):     at dalvik.system.NativeStart.main(Native Method)

错误显示在这里

用于双模式的AlbumFragMent类代码中的

是

if (mDualPane) {
    AlbumDetailFragment details = (AlbumDetailFragment) getFragmentManager()
            .findFragmentById(R.id.fragment_details);
    if (details == null || details.getShownIndex() != index) {
        // Make new fragment to show this selection.
        details = AlbumDetailFragment.newInstance(index);

        // Execute a transaction, replacing any existing fragment
        // with this one inside the frame.
        FragmentTransaction ft = getFragmentManager()
                .beginTransaction();
        ft.replace(R.id.fragment_details, details);
        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
        ft.commit();

    }
}

并在SongFragment类

中

if (mDualPane) {
    getListView().setItemChecked(index, true);

    SongDetailsFragment details = (SongDetailsFragment) getFragmentManager()
            .findFragmentById(R.id.fragment_details);
    if (details == null || details.getShownIndex() != index) {
        // Make new fragment to show this selection.
        details = SongDetailsFragment.newInstance(index);

        // Execute a transaction, replacing any existing fragment
        // with this one inside the frame.
        FragmentTransaction ft = getFragmentManager()
                .beginTransaction();
        ft.replace(R.id.fragment_details, details);
        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
        ft.commit();
    }
}

唯一不同的是正在调用的Detail片段类。

我做错了吗？

还有什么我们需要照顾的。

Answer 1

好吧，我解决了这个问题......解决方案有点奇怪，但对我有用。

我决定使用常见的detail-fragment类，而不是为每个选项卡分别使用片段类。并根据当前当前选择显示内容。

Fragment和ViewPager ClassCastException

1 个答案: