Question

我一直在为这个程序工作，感觉就像是永远的，我觉得我很接近它实际上工作，但是当我关闭抽屉时，它关闭一半会改变页面标题然后崩溃应用程序。我想我已经指出实际发生错误的地方，但对于我的生活，我看不到它。

我已经浏览了developer.android.com上的导航抽屉信息，我已经搜索了问题，但我似乎无法看到它是什么。

所以也许一双更有经验的新眼睛可以找到它。

这是我认为错误发生的代码部分。

private void selectItem(int position) {
    // Create a new fragment and specify the planet to show based on position
    Fragment fragment = new PageFragment();
    Bundle args = new Bundle();
    args.putInt(PageFragment.ARG_PAGE_NUMBER, position);
    fragment.setArguments(args);

    // Insert the fragment by replacing any existing fragment
    FragmentManager fragmentManager = getFragmentManager();
    fragmentManager.beginTransaction()
            .replace(R.id.content_frame, fragment)
            .commit();

    // Highlight the selected item, update the title, and close the drawer
    drawerList.setItemChecked(position, true);
    setTitle(colerainePages[position]);
    drawerLayout.closeDrawer(drawerList);
}

@Override
public void setTitle(CharSequence title) {
    mTitle = title;
    getActionBar().setTitle(mTitle);
}

private class DrawerItemClickListener implements ListView.OnItemClickListener {
    @Override
    public void onItemClick(AdapterView parent, View view, int position, long id) {
        selectItem(position);
    }
}

public static class PageFragment extends Fragment {
    public static final String ARG_PAGE_NUMBER = "page_number";

    public PageFragment() {
        // Empty constructor required for fragment subclasses
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        return rootView;
    }
}

logcat错误代码显示它是onCreateView方法中的“View rootView”行，似乎是说我的HomePage（我点击的按钮）没有设置为片段，但是在fragment_main.xml中，我把它设置为一个片段并拥有HomeScreen设置的类，所以它扩展了Fragment，无论如何都是错误堆栈：

    android.view.InflateException: Binary XML file line #9: Error inflating class fragment
            at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:710)
            at android.view.LayoutInflater.rInflate(LayoutInflater.java:752)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
                                                                                  com.project.ColeraineTownApp.MainActivity$PageFragment.onCreateView(MainActivity.java:146)
            at android.app.Fragment.performCreateView(Fragment.java:1699)
            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1075)
            at android.app.BackStackRecord.run(BackStackRecord.java:682)
            at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1455)
            at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441)
            at android.os.Handler.handleCallback(Handler.java:725)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5306)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: android.app.Fragment$InstantiationException: Trying to instantiate a class com.project.ColeraineTownApp.HomePage that is not a Fragment
            at android.app.Fragment.instantiate(Fragment.java:584)
            at android.app.Fragment.instantiate(Fragment.java:560)
            at android.app.Activity.onCreateView(Activity.java:4850)
                at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:686)
                at android.view.LayoutInflater.rInflate(LayoutInflater.java:752)
                at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
                at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at                                                                             com.project.ColeraineTownApp.MainActivity$PageFragment.onCreateView(MainActivity.java:146)
            at android.app.Fragment.performCreateView(Fragment.java:1699)
            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1075)
            at android.app.BackStackRecord.run(BackStackRecord.java:682)

编辑：

我已经完成了代码并确保所有内容都调用片段，但是我仍然无法弄明白。

下面是HomePage类和fragment_main xml文件。

主页类：

package com.project.ColeraineTownApp;

import android.os.Bundle;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

    public class HomePage extends Fragment {
        @Override
        public View onCreateView(LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {

        // Inflate the layout for this fragment
        View view =  inflater.inflate(R.layout.home_fragment, container, false);
        return view;
        }
    }

fragment_main xml：

    <?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                xmlns:tools="http://schemas.android.com/tools"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                tools:context=".FragmentExampleActivity" >

    <fragment
            android:id="@+id/home_fragment"
            android:name="com.project.ColeraineTownApp.HomePage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            tools:layout="@layout/home_fragment" />

    <fragment
            android:id="@+id/shopping_fragment"
            android:name="com.project.ColeraineTownApp.Shopping"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            tools:layout="@layout/shopping_fragment" />
</RelativeLayout>

这是PageFragment类：

public static class PageFragment extends Fragment {
    public static final String ARG_PAGE_NUMBER = "page_number";

    public PageFragment() {
        // Empty constructor required for fragment subclasses
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        return rootView;
    }
}

请参阅上文，了解在inflater中调用的fragment_main xml

Answer 1

堆栈跟踪似乎表明您尝试将com.project.ColeraineTownApp.HomePage作为片段附加到您的活动的某个位置。此对象不会扩展android.app.Fragment，而FragmentManager会跳过它。

我无法根据您提供的代码找到原因，因此您可能希望在项目中搜索对HomePage的引用。它可能位于<fragment>标记中，特别是通过FragmentTransaction添加，或者可能被添加到TaskStackBuilder。

抽屉关闭时出错（碎片）

1 个答案: