Android教程MyFirstApp立即崩溃，代码中没有错误

我正试图通过androids简介教程创建MyFirstApp应用程序，当它启动时，它立即崩溃，不幸的是，MyFirstApp已经停止。代码中没有错误，但以下是logcat输出：

03-30 21:10:54.529: W/dalvikvm(27006): Unable to resolve superclass of Lcom/example/myfirstapp/MainActivity; (5)
03-30 21:10:54.529: W/dalvikvm(27006): Link of class 'Lcom/example/myfirstapp/MainActivity;' failed
03-30 21:10:54.529: D/AndroidRuntime(27006): Shutting down VM
03-30 21:10:54.529: W/dalvikvm(27006): threadid=1: thread exiting with uncaught exception (group=0x416feda0)
03-30 21:10:54.529: E/AndroidRuntime(27006): FATAL EXCEPTION: main
03-30 21:10:54.529: E/AndroidRuntime(27006): Process: com.example.myfirstapp, PID: 27006
03-30 21:10:54.529: E/AndroidRuntime(27006): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.myfirstapp/com.example.myfirstapp.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.myfirstapp.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.myfirstapp-9.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.myfirstapp-9, /vendor/lib, /system/lib]]
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2231)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.ActivityThread.access$900(ActivityThread.java:161)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.os.Handler.dispatchMessage(Handler.java:102)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.os.Looper.loop(Looper.java:157)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.ActivityThread.main(ActivityThread.java:5356)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at java.lang.reflect.Method.invokeNative(Native Method)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at java.lang.reflect.Method.invoke(Method.java:515)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at dalvik.system.NativeStart.main(Native Method)
03-30 21:10:54.529: E/AndroidRuntime(27006): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.myfirstapp.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.myfirstapp-9.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.myfirstapp-9, /vendor/lib, /system/lib]]
03-30 21:10:54.529: E/AndroidRuntime(27006):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:67)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.Instrumentation.newActivity(Instrumentation.java:1079)
03-30 21:10:54.529: E/AndroidRuntime(27006):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2222)
03-30 21:10:54.529: E/AndroidRuntime(27006):    ... 11 more

这是AndroidManifest.xml和MainActivity.java文件：

package com.example.myfirstapp;

import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
    }

    @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);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

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

}

这是舱单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myfirstapp"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.myfirstapp.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>

activiy_main.xml：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.myfirstapp.MainActivity"
    tools:ignore="MergeRootFrame" />

@FRSquid看起来不错。您有classnotfoundexception，但您的活动已在ManifestThank中声明为正常谢谢，我是新来这里发布的。@FRSquid您确定您发布的是完整的堆栈跟踪吗？执行清理/重建。我遗漏了logcat输出顶部的几行