Fragment - InstantiationException:no empty构造函数 - > Google地图v2? [英] Fragment - InstantiationException: no empty Constructor -> Google Maps v2?
问题描述
我通过应用更改按钮再次打开已关闭的应用时收到此错误消息:
导致:java .lang.InstantiationException:不能实例化类com。*。FragmentContact $ 1;没有空的构造函数
我找到了几个关于Inner-Classes的提示,此FragmentContact是 *。java文件和具有公共空构造函数中的公用类。
我在这个项目中使用Google Maps Api v2,并在互联网的某个地方设置我的MapView。查看这里:
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState){
查看v = inflater.inflate(R.layout.fragment_contact,null);
try {
MapsInitializer.initialize(this.getActivity()。getApplicationContext());
} catch(GooglePlayServicesNotAvailableException e){
e.printStackTrace();
}
fragment = new SupportMapFragment(){
@Override
public void onActivityCreated(Bundle savedInstanceState){
super.onActivityCreated savedInstanceState);
mMap = fragment.getMap();
if(mMap!= null){
setupMap();
}
}
};
getFragmentManager()。beginTransaction()。replace(R.id.fragment_orte_map_parent,fragment).commit();
return v;
}
当我剪切这个MapView的东西一切正常。也许有人可以解释我做错了什么。
我完整的Stacktrace:
04-17 16:15:22.115:E / AndroidRuntime(22182):FATAL EXCEPTION:main
$ p $但是这些FragmentContact是一个* .java文件中的公共类,并且有一个公共的空构造函数(public empty constructor) 。
04-17 16:15:22.115:E / AndroidRuntime(22182):java.lang.RuntimeException:无法启动活动ComponentInfo {com。* / com。*。MainActivity}:android.support.v4.app.Fragment $ InstantiationException:无法实例化片段com。*。FragmentContact $ 1:确保类名存在,是public,有一个空的构造函数是public
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2307)
04-17 16 :15:22.115:E / AndroidRuntime(22182):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2357)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android。 app.ActivityThread.access $ 600(ActivityThread.java:153)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1247)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.os.Handler.dispatchMessage(Handler.java:99)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.os.Looper.loop(Looper.java:137)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.app.ActivityThread.main .java:5226)
04-17 16:15:22.115:E / AndroidRuntime(22182):at java.lang.reflect.Method.invokeNative(本地方法)
04-17 16:15: 22.115:E / AndroidRuntime(22182):在java.lang.reflect.Method.invoke(Method.java:511)
04-17 16:15:22.115:E / AndroidRuntime(22182):at com.android .internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:795)
04-17 16:15:22.115:E / AndroidRuntime(22182):在com.android.internal.os.ZygoteInit.main ZygoteInit.java:562)
04-17 16:15:22.115:E / AndroidRuntime(22182):在dalvik.system.NativeStart.main(本地方法)
04-17 16:15:22.115 :E / AndroidRuntime(22182):导致:android.support.v4.app.Fragment $ InstantiationException:无法实例化片段com。*。FragmentContact $ 1:确保类名存在,是public,并有一个空构造函数, public
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.support.v4.app.Fragment.instantiate(Fragment.java:405)
04-17 16:15 :22.115:E / AndroidRuntime(22182):在android.support.v4.app.FragmentState.instantiate(Fragment.java:97)
04-17 16:15:22.115:E / AndroidRuntime android.support.v4.app.FragmentManagerImpl.restoreAllState(FragmentManager.java:1767)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.support.v4.app.FragmentActivity.onCreate (FragmentActivity.java:208)
04-17 16:15:22.115:E / AndroidRuntime(22182):在com。*。MainActivity.onCreate(MainActivity.java:20)
04-17 16 :15:22.115:E / AndroidRuntime(22182):在android.app.Activity.performCreate(Activity.java:5104)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android。 app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
04-17 16:15:22.115:E / AndroidRuntime(22182):... 11更多
04-17 16:15:22.115:E / AndroidRuntime(22182):Caused by:java.lang.InstantiationException :不能实例化类com。*。FragmentContact $ 1;没有空构造函数
04-17 16:15:22.115:E / AndroidRuntime(22182):在java.lang.Class.newInstanceImpl(本地方法)
04-17 16:15:22.115:E / AndroidRuntime(22182):在java.lang.Class.newInstance(Class.java:1319)
04-17 16:15:22.115:E / AndroidRuntime(22182):在android.support.v4.app.Fragment .instantiate(Fragment.java:394)
04-17 16:15:22.115:E / AndroidRuntime(22182):... 18 more
错误不是抱怨
FragmentContact
。它正在抱怨FragmentContact
(FragmentContact $ 1
)的第一个内部类。您不能将Fragment
实现为任何内部类,因为它不能从外部类实例化。static
内部类很好。I get this error message, when I open a closed App again via App-Change button:
Caused by: java.lang.InstantiationException: can't instantiate class com.*.FragmentContact$1; no empty constructor
I've found several tips about Inner-Classes and to make them static etc. But this FragmentContact is a public class in a *.java-file and has a public empty constructor. I'm using Google Maps Api v2 in this project and do a trick somewhere from the internet to setup my MapView. Look here:
@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View v = inflater.inflate(R.layout.fragment_contact, null); try { MapsInitializer.initialize(this.getActivity().getApplicationContext()); } catch (GooglePlayServicesNotAvailableException e) { e.printStackTrace(); } fragment = new SupportMapFragment() { @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); mMap = fragment.getMap(); if (mMap != null) { setupMap(); } } }; getFragmentManager().beginTransaction().replace(R.id.fragment_orte_map_parent, fragment).commit(); return v; }
When I cut this MapView-thing out everything work fine. Maybe someone can explain what I'm doing wrong.
My complete Stacktrace:
04-17 16:15:22.115: E/AndroidRuntime(22182): FATAL EXCEPTION: main 04-17 16:15:22.115: E/AndroidRuntime(22182): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.*/com.*.MainActivity}: android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment com.*.FragmentContact$1: make sure class name exists, is public, and has an empty constructor that is public 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2307) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2357) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.ActivityThread.access$600(ActivityThread.java:153) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1247) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.os.Handler.dispatchMessage(Handler.java:99) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.os.Looper.loop(Looper.java:137) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.ActivityThread.main(ActivityThread.java:5226) 04-17 16:15:22.115: E/AndroidRuntime(22182): at java.lang.reflect.Method.invokeNative(Native Method) 04-17 16:15:22.115: E/AndroidRuntime(22182): at java.lang.reflect.Method.invoke(Method.java:511) 04-17 16:15:22.115: E/AndroidRuntime(22182): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795) 04-17 16:15:22.115: E/AndroidRuntime(22182): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562) 04-17 16:15:22.115: E/AndroidRuntime(22182): at dalvik.system.NativeStart.main(Native Method) 04-17 16:15:22.115: E/AndroidRuntime(22182): Caused by: android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment com.*.FragmentContact$1: make sure class name exists, is public, and has an empty constructor that is public 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.support.v4.app.Fragment.instantiate(Fragment.java:405) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.support.v4.app.FragmentState.instantiate(Fragment.java:97) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.support.v4.app.FragmentManagerImpl.restoreAllState(FragmentManager.java:1767) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:208) 04-17 16:15:22.115: E/AndroidRuntime(22182): at com.*.MainActivity.onCreate(MainActivity.java:20) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.Activity.performCreate(Activity.java:5104) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261) 04-17 16:15:22.115: E/AndroidRuntime(22182): ... 11 more 04-17 16:15:22.115: E/AndroidRuntime(22182): Caused by: java.lang.InstantiationException: can't instantiate class com.*.FragmentContact$1; no empty constructor 04-17 16:15:22.115: E/AndroidRuntime(22182): at java.lang.Class.newInstanceImpl(Native Method) 04-17 16:15:22.115: E/AndroidRuntime(22182): at java.lang.Class.newInstance(Class.java:1319) 04-17 16:15:22.115: E/AndroidRuntime(22182): at android.support.v4.app.Fragment.instantiate(Fragment.java:394) 04-17 16:15:22.115: E/AndroidRuntime(22182): ... 18 more
解决方案But these FragmentContact is a public class in a *.java-file and has a public empty constructor.
The error is not complaining about
FragmentContact
. It is complaining about the first inner class ofFragmentContact
(FragmentContact$1
). You cannot have aFragment
implemented as an inner class of anything, as it cannot be instantiated from outside the outer class. Astatic
inner class is fine.这篇关于Fragment - InstantiationException:no empty构造函数 - > Google地图v2?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IT屋!