Android致命异常无法恢复活动

Question

嗨everybodi！

我是Android编程新手，正在尝试使用Zxing创建一个QR代码阅读器应用。当我在手机中启动应用程序时，它会给我这个错误消息。应用程序启动后，我按下按钮然后抛出...问题是什么？

这是我的代码：这是MainActivity

package com.example;
public class MainActivity extends Activity {

private Button scan;

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

    scan= (Button)findViewById(R.id.button1);

    scan.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub  
            Intent intent = new Intent("com.google.zxing.client.android.SCAN");
            intent.putExtra("SCAN_MODE", "QR_CODE_MODE");
            startActivityForResult(intent, 0);
        }
    });
}

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
       if (requestCode == 0) {
          if (resultCode == RESULT_OK) {

             String contents = intent.getStringExtra("SCAN_RESULT");
             String format = intent.getStringExtra("SCAN_RESULT_FORMAT");

             // Handle successful scan

          } else if (resultCode == RESULT_CANCELED) {
             // Handle cancel
             Log.i("App","Scan unsuccessful");
          }
     }
  }

@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;
}
}

这是我的AndoridManifest

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

<uses-sdk
    android:minSdkVersion="10"
    android:targetSdkVersion="18" />

<uses-permission android:name="android.permission.CAMERA"/>

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

    <activity
           android:name="com.google.zxing.client.android.CaptureActivity"
           android:screenOrientation="landscape"
           android:configChanges="orientation|keyboardHidden"
           android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
           android:windowSoftInputMode="stateAlwaysHidden">
           <intent-filter>
              <action android:name="android.intent.action.MAIN"/>
              <category android:name="android.intent.category.DEFAULT"/>
           </intent-filter>
           <intent-filter>
              <action android:name="com.google.zxing.client.android.SCAN"/>
              <category android:name="android.intent.category.DEFAULT"/>
           </intent-filter>
    </activity>
</application>
</manifest>