我有一个带有三个选项卡的应用程序。

每个选项卡都有自己的布局.xml文件。xml有自己的映射片段。它是应用程序第一次启动时显示的那个。

一切都很好,除了当我在制表符之间改变。如果我尝试切换回地图片段选项卡,我会得到这个错误。在其他选项卡之间切换就可以了。

这里会出什么问题呢?

这是我的主类和main.xml,以及我使用的相关类(您还将在底部找到错误日志)

主类

package com.nfc.demo;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.widget.Toast;

public class NFCDemoActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ActionBar bar = getActionBar();
        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);

        bar.addTab(bar
                .newTab()
                .setText("Map")
                .setTabListener(
                        new TabListener<MapFragment>(this, "map",
                                MapFragment.class)));
        bar.addTab(bar
                .newTab()
                .setText("Settings")
                .setTabListener(
                        new TabListener<SettingsFragment>(this, "settings",
                                SettingsFragment.class)));
        bar.addTab(bar
                .newTab()
                .setText("About")
                .setTabListener(
                        new TabListener<AboutFragment>(this, "about",
                                AboutFragment.class)));

        if (savedInstanceState != null) {
            bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
        }
        // setContentView(R.layout.main);

    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
    }

    public static class TabListener<T extends Fragment> implements
            ActionBar.TabListener {
        private final Activity mActivity;
        private final String mTag;
        private final Class<T> mClass;
        private final Bundle mArgs;
        private Fragment mFragment;

        public TabListener(Activity activity, String tag, Class<T> clz) {
            this(activity, tag, clz, null);
        }

        public TabListener(Activity activity, String tag, Class<T> clz,
                Bundle args) {
            mActivity = activity;
            mTag = tag;
            mClass = clz;
            mArgs = args;

            // Check to see if we already have a fragment for this tab,
            // probably from a previously saved state. If so, deactivate
            // it, because our initial state is that a tab isn't shown.
            mFragment = mActivity.getFragmentManager().findFragmentByTag(mTag);
            if (mFragment != null && !mFragment.isDetached()) {
                FragmentTransaction ft = mActivity.getFragmentManager()
                        .beginTransaction();
                ft.detach(mFragment);
                ft.commit();
            }
        }

        public void onTabSelected(Tab tab, FragmentTransaction ft) {
            if (mFragment == null) {
                mFragment = Fragment.instantiate(mActivity, mClass.getName(),
                        mArgs);
                ft.add(android.R.id.content, mFragment, mTag);
            } else {
                ft.attach(mFragment);
            }
        }

        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
            if (mFragment != null) {
                ft.detach(mFragment);
            }
        }

        public void onTabReselected(Tab tab, FragmentTransaction ft) {
            Toast.makeText(mActivity, "Reselected!", Toast.LENGTH_SHORT)
                         .show();
        }
    }

}

main。xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <fragment
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/mapFragment"
        android:name="com.google.android.gms.maps.MapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

相关类:MapFragment.java

package com.nfc.demo;

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

public class MapFragment extends Fragment {

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

    public void onDestroy() {
        super.onDestroy();
    }
}

错误

android.view.InflateException: Binary XML file line #7: 
     Error inflating class fragment
   at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
   at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
   at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
   at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
   at com.nfc.demo.MapFragment.onCreateView(MapFragment.java:15)
   at android.app.Fragment.performCreateView(Fragment.java:1695)
   at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:885)
   at android.app.FragmentManagerImpl.attachFragment(FragmentManager.java:1255)
   at android.app.BackStackRecord.run(BackStackRecord.java:672)
   at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435)
   at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441)
   at android.os.Handler.handleCallback(Handler.java:725)
   at android.os.Handler.dispatchMessage(Handler.java:92)
   at android.os.Looper.loop(Looper.java:137)
   at android.app.ActivityThread.main(ActivityThread.java:5039)
   at java.lang.reflect.Method.invokeNative(Native Method)
   at java.lang.reflect.Method.invoke(Method.java:511)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
   at dalvik.system.NativeStart.main(Native Method)

Caused by: java.lang.IllegalArgumentException: 
     Binary XML file line #7: Duplicate id 0x7f040005, tag null, or 
     parent id 0xffffffff with another fragment for 
     com.google.android.gms.maps.MapFragment
   at android.app.Activity.onCreateView(Activity.java:4722)
   at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:680)
   ... 19 more

当前回答

我今天已经浪费了几个小时来寻找原因,幸运的是这个问题不是因为MapFragment实现,幸运的是,这并不奏效,因为嵌套片段只通过rev 11的支持库支持。

我的实现有一个带有actionbar(在选项卡模式下)的活动,有两个选项卡(没有viewpager),一个有地图,另一个有条目列表。当然,我很天真地在我的标签片段中使用MapFragment,等我每次切换回地图标签时,应用程序就崩溃了。

(同样的问题,我也会有情况下,我的制表符片段将膨胀任何布局包含任何其他片段)。

一种选择是使用MapView(而不是MapFragment),尽管有一些开销(请参阅layout.xml中的MapView Docs作为dropin替代品,另一种选择是使用从rev. 11开始的支持库,但随后采用编程方法,因为布局不支持嵌套片段。或者只是通过显式地破坏片段以编程方式工作(就像Matt / Vidar的答案一样),顺便说一句:使用MapView(选项1)也能达到同样的效果。

但实际上,我不想每次我tab离开的时候都丢失地图,也就是说,我想把它保存在内存中,只有在活动关闭时才清理,所以我决定在tab时简单地隐藏/显示地图,参见FragmentTransaction / hide

其他回答

尝试为你的mapView父布局设置一个id (android:id="@+id/maps_dialog")。对我有用。

如果你只使用Vidar Wahlberg的答案,当你打开其他活动(例如)并返回到地图时,你会得到错误。或者在我的情况下打开其他活动,然后从新的活动打开地图再次(不使用后退按钮)。 但是当你结合维达尔·沃尔伯格解决方案和马特解决方案时,你将没有例外。

布局

<com.example.ui.layout.MapWrapperLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/map_relative_layout">

    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/root">

        <fragment xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/map"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            class="com.google.android.gms.maps.SupportMapFragment" />
    </RelativeLayout>
</<com.example.ui.layout.MapWrapperLayout>

片段

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    setHasOptionsMenu(true);
    if (view != null) {
        ViewGroup parent = (ViewGroup) view.getParent();
        if (parent != null){
            parent.removeView(view);
        }
    }
    try {
        view = inflater.inflate(R.layout.map_view, null);
        if(view!=null){
            ViewGroup root = (ViewGroup) view.findViewById(R.id.root);
...

@Override
public void onDestroyView() {
    super.onDestroyView();
    Fragment fragment = this.getSherlockActivity().getSupportFragmentManager().findFragmentById(R.id.map);
    if (fragment != null)
        getFragmentManager().beginTransaction().remove(fragment).commit();
}

As mentioned by @Justin Breitfeller, @Vidar Wahlberg solution is a hack which might not work in future version of Android. @Vidar Wahlberg perfer a hack because other solution might "cause the map to be recreated and redrawn, which isn't always desirable". Map redraw could be prevented by maintaining the old map fragment, rather than creating a new instance every time. @Matt solution doesn't work for me (IllegalStateException) As quoted by @Justin Breitfeller, "You cannot inflate a layout into a fragment when that layout includes a . Nested fragments are only supported when added to a fragment dynamically."

我的解决方案:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,                              Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_map_list, container, false);

    // init
    //mapFragment = (SupportMapFragment)getChildFragmentManager().findFragmentById(R.id.map);
    // don't recreate fragment everytime ensure last map location/state are maintain
    if (mapFragment == null) {
        mapFragment = SupportMapFragment.newInstance();
        mapFragment.getMapAsync(this);
    }
    FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
    // R.id.map is a layout
    transaction.replace(R.id.map, mapFragment).commit();

    return view;
}

我有同样的问题,并能够通过手动删除碎片类的onDestroy()方法中的MapFragment来解决。下面是在XML中通过ID引用MapFragment的代码:

@Override
public void onDestroyView() {
    super.onDestroyView();
    MapFragment f = (MapFragment) getFragmentManager()
                                         .findFragmentById(R.id.map);
    if (f != null) 
        getFragmentManager().beginTransaction().remove(f).commit();
}

如果你不手动删除MapFragment,它会一直挂在那里,这样就不会花费很多资源来重新创建/显示地图视图。看起来,保持底层MapView对于在选项卡之间来回切换是很好的,但是当在片段中使用时,这种行为会导致在每个新的MapFragment上创建一个具有相同ID的重复MapView。解决方案是手动删除MapFragment,从而在每次膨胀片段时重新创建底层映射。

我在另一个答案[1]中也提到了这一点。

这是我的回答:

1、创建一个如下所示的布局xml:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>

2、在Fragment类中,通过编程方式添加一个谷歌映射。

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * A simple {@link android.support.v4.app.Fragment} subclass. Activities that
 * contain this fragment must implement the
 * {@link MapFragment.OnFragmentInteractionListener} interface to handle
 * interaction events. Use the {@link MapFragment#newInstance} factory method to
 * create an instance of this fragment.
 * 
 */
public class MapFragment extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    private GoogleMap mMap;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_map, container, false);
        SupportMapFragment mMapFragment = SupportMapFragment.newInstance();
        mMap = mMapFragment.getMap();
        FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
        transaction.add(R.id.map_container, mMapFragment).commit();
        return view;
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        Log.d("Attach", "on attach");
    }

    @Override
    public void onDetach() {
        super.onDetach();
    }
}