我正在开发一个用于登录Facebook的应用程序。但是当它在本地设备中测试时它会崩溃.Log Cat说它是由 ClassNotFoundException引起的：没找到类“com.cheerz.citizengage.MainActivity”。请帮我解决一下
MainActivity.java
package com.cheerz.citizengage;
import com.facebook.AppEventsLogger;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends FragmentActivity {
private MainFragment mainFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
// Add the fragment on initial activity setup
mainFragment = new MainFragment();
getSupportFragmentManager()
.beginTransaction()
.add(android.R.id.content, mainFragment)
.commit();
} else {
// Or set the fragment from restored state info
mainFragment = (MainFragment) getSupportFragmentManager()
.findFragmentById(android.R.id.content);
}
}
@Override
protected void onResume() {
super.onResume();
// Logs 'install' and 'app activate' App Events.
AppEventsLogger.activateApp(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
protected void onPause() {
super.onPause();
// Logs 'app deactivate' App Event.
AppEventsLogger.deactivateApp(this);
}
}
MainFragment.java
package com.cheerz.citizengage;
import java.util.Arrays;
import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.UiLifecycleHelper;
import com.facebook.widget.LoginButton;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class MainFragment extends Fragment{
private static final String TAG = "MainFragment";
private UiLifecycleHelper uiHelper;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_main, container, false);
uiHelper = new UiLifecycleHelper(getActivity(), callback);
uiHelper.onCreate(savedInstanceState);
LoginButton authButton = (LoginButton) view.findViewById(R.id.authButton);
authButton.setFragment(this);
authButton.setReadPermissions(Arrays.asList("user_likes", "user_status"));
return view;
}
private void onSessionStateChange(Session session, SessionState state, Exception exception) {
if (state.isOpened()) {
Log.i(TAG, "Logged in...");
} else if (state.isClosed()) {
Log.i(TAG, "Logged out...");
}
}
private Session.StatusCallback callback = new Session.StatusCallback() {
@Override
public void call(Session session, SessionState state, Exception exception) {
onSessionStateChange(session, state, exception);
}
};
@Override
public void onResume() {
super.onResume();
Session session = Session.getActiveSession();
if (session != null &&
(session.isOpened() || session.isClosed()) ) {
onSessionStateChange(session, session.getState(), null);
}
uiHelper.onResume();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
uiHelper.onActivityResult(requestCode, resultCode, data);
}
@Override
public void onPause() {
super.onPause();
uiHelper.onPause();
}
@Override
public void onDestroy() {
super.onDestroy();
uiHelper.onDestroy();
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
uiHelper.onSaveInstanceState(outState);
}
}
activity_main.xml
<LinearLayout 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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.cheerz.citizengage.MainActivity" >
<com.facebook.widget.LoginButton
android:id="@+id/authButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="30dp"
/>
</LinearLayout>
Log Cat
01-09 14:32:30.163: W/dalvikvm(26973): Unable to resolve superclass of Lcom/cheerz/citizengage/MainActivity; (107)
01-09 14:32:30.163: W/dalvikvm(26973): Link of class 'Lcom/cheerz/citizengage/MainActivity;' failed
01-09 14:32:30.163: D/AndroidRuntime(26973): Shutting down VM
01-09 14:32:30.163: W/dalvikvm(26973): threadid=1: thread exiting with uncaught exception (group=0x41639930)
01-09 14:32:30.183: E/AndroidRuntime(26973): FATAL EXCEPTION: main
01-09 14:32:30.183: E/AndroidRuntime(26973): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.cheerz.citizengage/com.cheerz.citizengage.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.cheerz.citizengage.MainActivity" on path: /data/app/com.cheerz.citizengage-2.apk
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2309)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.ActivityThread.access$700(ActivityThread.java:157)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1289)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.os.Handler.dispatchMessage(Handler.java:99)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.os.Looper.loop(Looper.java:176)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.ActivityThread.main(ActivityThread.java:5317)
01-09 14:32:30.183: E/AndroidRuntime(26973): at java.lang.reflect.Method.invokeNative(Native Method)
01-09 14:32:30.183: E/AndroidRuntime(26973): at java.lang.reflect.Method.invoke(Method.java:511)
01-09 14:32:30.183: E/AndroidRuntime(26973): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
01-09 14:32:30.183: E/AndroidRuntime(26973): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
01-09 14:32:30.183: E/AndroidRuntime(26973): at dalvik.system.NativeStart.main(Native Method)
01-09 14:32:30.183: E/AndroidRuntime(26973): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.cheerz.citizengage.MainActivity" on path: /data/app/com.cheerz.citizengage-2.apk
01-09 14:32:30.183: E/AndroidRuntime(26973): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
01-09 14:32:30.183: E/AndroidRuntime(26973): at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
01-09 14:32:30.183: E/AndroidRuntime(26973): at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.Instrumentation.newActivity(Instrumentation.java:1071)
01-09 14:32:30.183: E/AndroidRuntime(26973): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2171)
01-09 14:32:30.183: E/AndroidRuntime(26973): ... 11 more