“无法实例化活动ComponentInfo”

我是一个全新的android开发的所有人，我试图找出这个异常的原因。“无法实例化活动ComponentInfo”

11-09 02:29:39.897: E/AndroidRuntime(657): FATAL EXCEPTION: main 
11-09 02:29:39.897: E/AndroidRuntime(657): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.yoursite.arduinoblinkled/com.yoursite.arduinoblinkled.activity_arduino_blink_led}: java.lang.ClassNotFoundException: com.yoursite.arduinoblinkled.activity_arduino_blink_led 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.ActivityThread.access$600(ActivityThread.java:123) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.os.Handler.dispatchMessage(Handler.java:99) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.os.Looper.loop(Looper.java:137) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.ActivityThread.main(ActivityThread.java:4424) 
11-09 02:29:39.897: E/AndroidRuntime(657): at java.lang.reflect.Method.invokeNative(Native Method) 
11-09 02:29:39.897: E/AndroidRuntime(657): at java.lang.reflect.Method.invoke(Method.java:511) 
11-09 02:29:39.897: E/AndroidRuntime(657): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
11-09 02:29:39.897: E/AndroidRuntime(657): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
11-09 02:29:39.897: E/AndroidRuntime(657): at dalvik.system.NativeStart.main(Native Method) 
11-09 02:29:39.897: E/AndroidRuntime(657): Caused by: java.lang.ClassNotFoundException: com.yoursite.arduinoblinkled.activity_arduino_blink_led 
11-09 02:29:39.897: E/AndroidRuntime(657): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61) 
11-09 02:29:39.897: E/AndroidRuntime(657): at java.lang.ClassLoader.loadClass(ClassLoader.java:501) 
11-09 02:29:39.897: E/AndroidRuntime(657): at java.lang.ClassLoader.loadClass(ClassLoader.java:461) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.Instrumentation.newActivity(Instrumentation.java:1023) 
11-09 02:29:39.897: E/AndroidRuntime(657): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871) 
11-09 02:29:39.897: E/AndroidRuntime(657): ... 11 more

AndroidManifest.xml中

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

    <uses-sdk 
     android:minSdkVersion="15" 
     android:targetSdkVersion="15" /> 

    <application android:icon="@drawable/ic_launcher" android:label="@string/app_name"> 
     <uses-library android:name="com.google.android.maps" /> 
     <activity android:name=".activity_arduino_blink_led" 
      android:label="@string/app_name"> 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 
       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
      <intent-filter> 
       <action android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED" /> 
      </intent-filter> 
      <meta-data android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED" 
       android:resource="@xml/device_filter" /> 
     </activity> 

     <uses-library android:name="com.android.future.usb.accessory"></uses-library> 

    </application> 
</manifest>

ArduinoBlinkLEDActivity.java

package com.example.arduinoblinkled; 

import java.io.FileDescriptor; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 


import com.android.future.usb.UsbAccessory; 
import com.android.future.usb.UsbManager; 
import com.yoursite.arduinoblinkled.R; 


import android.os.Bundle; 
import android.os.ParcelFileDescriptor; 
import android.app.Activity; 
import android.app.PendingIntent; 
import android.content.BroadcastReceiver; 
import android.content.Context; 
import android.content.Intent; 
import android.content.IntentFilter; 
import android.util.Log; 
import android.view.Menu; 
import android.view.View; 
import android.widget.ToggleButton; 

public class ArduinoBlinkLEDActivity extends Activity { 




     private static final String TAG = "ArduinoAccessory"; 

     private static final String ACTION_USB_PERMISSION = "com.google.android.DemoKit.action.USB_PERMISSION"; 

     private UsbManager mUsbManager; 
     private PendingIntent mPermissionIntent; 
     private boolean mPermissionRequestPending; 
     private ToggleButton buttonLED; 

     UsbAccessory mAccessory; 
     ParcelFileDescriptor mFileDescriptor; 
     FileInputStream mInputStream; 
     FileOutputStream mOutputStream; 

     private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() { 
      @Override 
      public void onReceive(Context context, Intent intent) { 
       String action = intent.getAction(); 
       if (ACTION_USB_PERMISSION.equals(action)) { 
        synchronized (this) { 
         UsbAccessory accessory = UsbManager.getAccessory(intent); 
         if (intent.getBooleanExtra(
           UsbManager.EXTRA_PERMISSION_GRANTED, false)) { 
          openAccessory(accessory); 
         } else { 
          Log.d(TAG, "permission denied for accessory " 
            + accessory); 
         } 
         mPermissionRequestPending = false; 
        } 
       } else if (UsbManager.ACTION_USB_ACCESSORY_DETACHED.equals(action)) { 
        UsbAccessory accessory = UsbManager.getAccessory(intent); 
        if (accessory != null && accessory.equals(mAccessory)) { 
         closeAccessory(); 
        } 
       } 
      } 
     }; 


    @SuppressWarnings("deprecation") 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_arduino_blink_led); 

     mUsbManager = UsbManager.getInstance(this); 
     mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0); 
     IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION); 
     filter.addAction(UsbManager.ACTION_USB_ACCESSORY_DETACHED); 
     registerReceiver(mUsbReceiver, filter); 

     if (getLastNonConfigurationInstance() != null) { 
      mAccessory = (UsbAccessory) getLastNonConfigurationInstance(); 
      openAccessory(mAccessory); 
     } 

     setContentView(R.layout.activity_arduino_blink_led); 
     buttonLED = (ToggleButton) findViewById(R.id.toggleButtonLED); 
    } 

    @SuppressWarnings("deprecation") 
    @Override 
    public Object onRetainNonConfigurationInstance() { 
     if (mAccessory != null) { 
      return mAccessory; 
     } else { 
      return super.onRetainNonConfigurationInstance(); 
     } 
    } 

    @Override 
    public void onResume() { 
     super.onResume(); 

     if (mInputStream != null && mOutputStream != null) { 
      return; 
     } 

     UsbAccessory[] accessories = mUsbManager.getAccessoryList(); 
     UsbAccessory accessory = (accessories == null ? null : accessories[0]); 
     if (accessory != null) { 
      if (mUsbManager.hasPermission(accessory)) { 
       openAccessory(accessory); 
      } else { 
       synchronized (mUsbReceiver) { 
        if (!mPermissionRequestPending) { 
         mUsbManager.requestPermission(accessory,mPermissionIntent); 
         mPermissionRequestPending = true; 
        } 
       } 
      } 
     } else { 
      Log.d(TAG, "mAccessory is null"); 
     } 
    } 

    private void openAccessory(UsbAccessory accessory) { 
     mFileDescriptor = mUsbManager.openAccessory(accessory); 
     if (mFileDescriptor != null) { 
      mAccessory = accessory; 
      FileDescriptor fd = mFileDescriptor.getFileDescriptor(); 
      mInputStream = new FileInputStream(fd); 
      mOutputStream = new FileOutputStream(fd); 
      Log.d(TAG, "accessory opened"); 
     } else { 
      Log.d(TAG, "accessory open fail"); 
     } 
    } 


    private void closeAccessory() { 
     try { 
      if (mFileDescriptor != null) { 
       mFileDescriptor.close(); 
      } 
     } catch (IOException e) { 
     } finally { 
      mFileDescriptor = null; 
      mAccessory = null; 
     } 
    } 

    public void blinkLED(View v){ 

     byte[] buffer = new byte[1]; 

     if(buttonLED.isChecked()) 
      buffer[0]=(byte)0; // button says on, light is off 
     else 
      buffer[0]=(byte)1; // button says off, light is on 

     if (mOutputStream != null) { 
      try { 
       mOutputStream.write(buffer); 
      } catch (IOException e) { 
       Log.e(TAG, "write failed", e); 
      } 
     } 
    } 


}

我尝试了很多解决方案，但问题仍然没有解决。有谁知道这可能是什么原因造成的？非常感谢。

来源

2012-11-09 Ali Mustafa

至于，你不使用全名对于活动，将顶部的软件包名称更改为com.example.arduinoblinkled。

也改变了活动名称为.ArduinoBlinkLEDActivity

来源

2012-11-09 01:50:51

该问题已得到解决。当我在android模拟器上执行它时，它工作正常。但是当我导出到APK时，我在我的移动设备上测试它不起作用消息“不幸的是，ArduinoBlinkLED已经停止”。我不知道为什么！如何才能找出我的手机上的问题？ –

你能得到logcat输出吗？ –

您注册活动的清单与android:name=".activity_arduino_blink_led"的名字，但在代码中你有活动ArduinoBlinkLEDActivity所以它更改为

<activity android:name=".ArduinoBlinkLEDActivity"

，而不是

<activity android:name=".activity_arduino_blink_led"

来源

2012-11-09 01:11:00

它应该还是有'.'：'机器人：名字= “ArduinoBlinkLEDActivity”' – Eric

@Eric既会工作，要么有<活动'机器人：名字= “.ArduinoBlinkLEDActivity”或

有趣。我以前遇到过这个问题，[文档]（http://developer.android.com/guide/topics/manifest/activity-element.html#nm）建议使用'.'，所以这就是我传。 ;） – Eric

“无法实例化活动ComponentInfo”

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