我得到一个无法实例化Fragment错误，因为找不到类的异常。以前这段代码使用工作正常，我不知道发生了什么变化，我一直试图解决这个问题几个小时了。
package com.whatshappening;
// A bunch of imports
public class AddEvents extends Fragment implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener, AsyncResponse, locationChangeListner {
// Class Variables
private ProgressDialog pd;
private LocationClient mLocationClient;
private FragmentActivity myContext;
private String resultString;
public String LatLng = null;
public EditText locationAddress = null;
public Double Lat = null;
public Double Lng = null;
public Double lat = null;
public Double lng = null;
// Constructor is empty and public
public AddEvents(){
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.add_events, container, false);
locationAddress = (EditText) rootView.findViewById(R.id.tLocation);
mLocationClient = new LocationClient(getActivity(), this, this);
rootView.findViewById(R.id.locButton).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
pd = ProgressDialog.show(getActivity(), "",
"Finding you!!!", false);
getAddress(v);
}
});
rootView.findViewById(R.id.shButton).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
if ((Lat != null) && (Lng != null)) {
Toast.makeText(getActivity(),
LatLng, Toast.LENGTH_SHORT).show();
locationChange(Lat,Lng);
} else {
Toast.makeText(getActivity(),
"No location was found", Toast.LENGTH_SHORT).show();
}
}
});
return rootView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
// Class is much Larger but I don't think that's the issue.
}
package com.whatshappening;
//Bunch of imports
public class MainActivity extends ActionBarActivity implements
ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a {@link FragmentPagerAdapter}
* derivative, which will keep every loaded fragment in memory. If this
* becomes too memory intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Set up date in Action Bar
String dateString = (String) DateFormat.format("MM-dd-yyyy",
new java.util.Date());
actionBar.setSubtitle(dateString);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager
.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onTabSelected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public android.support.v4.app.Fragment getItem(int position) {
switch (position) {
case (0):
return new AddEvents();
case (1):
return new EventMap();
}
return null;
}
@Override
public int getCount() {
// Show 2 total pages.
return 2;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
}
return null;
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.whatshappening"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<!--
The following two permissions are not required to use
Google Maps Android API v2, but are recommended.
-->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light" >
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyCO5Wb1Ow2W3Wq0mB64OFIPwTvGLbCRS9k" />
<activity
android:name="com.whatshappening.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
07-19 19:46:15.880: E/AndroidRuntime(29720): Caused by: android.app.Fragment$InstantiationException: Unable to instantiate fragment com.example.fragment.AddEvents: make sure class name exists, is public, and has an empty constructor that is public
07-19 19:46:15.880: E/AndroidRuntime(29720): at android.app.Fragment.instantiate(Fragment.java:597)
07-19 19:46:15.880: E/AndroidRuntime(29720): at android.app.Fragment.instantiate(Fragment.java:561)
07-19 19:46:15.880: E/AndroidRuntime(29720): at android.app.Activity.onCreateView(Activity.java:4964)
07-19 19:46:15.880: E/AndroidRuntime(29720): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:695)
07-19 19:46:15.880: E/AndroidRuntime(29720): ... 24 more
07-19 19:46:15.880: E/AndroidRuntime(29720): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.fragment.AddEvents" on path: DexPathList[[zip file "/data/app/com.whatshappening-13.apk"],nativeLibraryDirectories=[/data/app-lib/com.whatshappening-13, /vendor/lib, /system/lib]]
07-19 19:46:15.880: E/AndroidRuntime(29720): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:67)
07-19 19:46:15.880: E/AndroidRuntime(29720): at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
07-19 19:46:15.880: E/AndroidRuntime(29720): at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
07-19 19:46:15.880: E/AndroidRuntime(29720): at android.app.Fragment.instantiate(Fragment.java:583)
07-19 19:46:15.880: E/AndroidRuntime(29720): ... 27 more
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/beaver"
android:orientation="vertical" >
<TextView
android:id="@+id/tVName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="20dp"
android:layout_marginTop="30dp"
android:text="Event Name:"
android:textColor="@android:color/white"
android:textSize="22sp" />
<Button
android:id="@+id/locButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/tLocation"
android:layout_alignBottom="@+id/tLocation"
android:layout_alignParentRight="true"
android:text="Get Location"
android:textColor="#ffffff" />
<EditText
android:id="@+id/tLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/tVLocation"
android:layout_marginTop="25dp"
android:layout_toLeftOf="@+id/locButton"
android:ems="10"
android:textColor="@android:color/white" />
<EditText
android:id="@+id/tTime"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tVTime"
android:layout_below="@+id/tVTime"
android:layout_marginTop="22dp"
android:ems="10"
android:inputType="textMultiLine|date"
android:textColor="@android:color/white" />
<TextView
android:id="@+id/tVDescription"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/tDescription"
android:layout_alignLeft="@+id/tTime"
android:layout_marginBottom="18dp"
android:text="Description:"
android:textColor="@android:color/white"
android:textSize="22sp" />
<EditText
android:id="@+id/tNames"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tVLocation"
android:layout_below="@+id/tVName"
android:layout_marginTop="10dp"
android:ems="10"
android:textColor="@android:color/white" />
<EditText
android:id="@+id/tDescription"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/shButton"
android:layout_alignLeft="@+id/tVDescription"
android:layout_marginBottom="7dp"
android:ems="10"
android:inputType="textMultiLine"
android:textColor="@android:color/white" />
<TextView
android:id="@+id/tVTime"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tVLocation"
android:layout_below="@+id/locButton"
android:layout_marginTop="16dp"
android:text="Time:"
android:textColor="@android:color/white"
android:textSize="22sp" />
<TextView
android:id="@+id/tVLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tVName"
android:layout_below="@+id/tNames"
android:layout_marginTop="15dp"
android:text="Location:"
android:textColor="@android:color/white"
android:textSize="22sp" />
<Button
android:id="@+id/shButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="31dp"
android:layout_toRightOf="@+id/tDescription"
android:text="Share"
android:textColor="#ffffff" />
</RelativeLayout>
我觉得错误一定是非常基本的。但是我没有改变以前“工作”版本的应用程序的任何变化。
答案 0 :(得分：1)
未找到类“com.example.fragment.AddEvents”
AddEvents的包名称是
package com.whatshappening;
不
com.example.fragment
在你的布局中看起来你有片段而且包名与片段中的名称不匹配