Android Broadcast Receiver Error: Class not found exception

问题

I have a Broadcast receiver setup so that a pop-up message is displayed to the user after each upgrade of my app, or if this is the first time the package is installed. I tested this on my Droid running Android 2.2 both as a fresh install and after upgrading my app, as well in the Emulator running 1.5 and 1.6, and I see everything run fine.

However, I received an error report from a user that lists the following exception:

java.lang.RuntimeException: Unable to instantiate receiver 
com.name.pkg.FirstRunBroadcastReceiver: java.lang.ClassNotFoundException: com.name.pkg.app_name.FirstRunBroadcastReceiver in loader dalvik.system.PathClassLoader[/data/app/com.name.pkg.app_name.apk]
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2789)
at android.app.ActivityThread.access$3200(ActivityThread.java:125)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2083)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: com.name.pkg.app_name.FirstRunBroadcastReceiver in loader dalvik.system.PathClassLoader[/data/app/com.name.pkg.app_name.apk]
at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2780)
... 10 more

Can someone tell me why one of my users received this exception?

In my Manifest file, I have things setup like this:

<receiver android:name=".FirstRunBroadcastReceiver">
    <intent-filter>
        <action android:name="android.intent.action.PACKAGE_REPLACE"/>
        <data android:scheme="package" android:path="com.name.pkg.app_name">
    </intent-filter>
</receiver>

The class FirstRunBroadcastReceiver is setup like this:

package com.name.pkg.app_name;

public class FirstRunBroadcastReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Contenxt context, Intent intent)
    {
        Uri uri = intent.getData();
        if( uri.toString().compareTo("package:com.name.pkg.app_name") == 0 )
        {
            //set shared prefs data to determine if start-up message should be shown
        }
    }
}

Upon a first time install, the default value for the shared prefs is set so that the pop-up message will be displayed, but I wouldn't think that would have anything to do with this exception.

I tested it again, and I don't receive an exception. Thanks for any help you can provide.

回答1:

from the android documentation on "android:exported" attribute for a receiver:

Whether or not the broadcast receiver can receive messages from sources outside its application — "true" if it can, and "false" if not. If "false", the only messages the broadcast receiver can receive are those sent by components of the same application or applications with the same user ID. The default value depends on whether the broadcast receiver contains intent filters. The absence of any filters means that it can be invoked only by Intent objects that specify its exact class name. This implies that the receiver is intended only for application-internal use (since others would not normally know the class name). So in this case, the default value is "false". On the other hand, the presence of at least one filter implies that the broadcast receiver is intended to receive intents broadcast by the system or other applications, so the default value is "true"

Since your receiver has child intents the default value for android:exported is true. Just state this explicitly and it should function fine.

ie,

<receiver android:name=".FirstRunBroadcastReceiver" android:exported="true">
<intent-filter>
    <action android:name="android.intent.action.PACKAGE_REPLACE"/>
    <data android:scheme="package" android:path="com.name.pkg.app_name">
</intent-filter>

回答2:

Is package declaration in your FirstRunBroadcastReceiver class as follows?

package com.name.pkg.app_name;

According to your exception stack it should be so.

回答3:

I am a newbie with android development and my solution was a simple one caused my stupidity. I had renamed my broadcastreceiver file and when I tried to run the application I received the classdefnotfound error. I ended up cleaning and rebuilding the project and the error was removed.

来源：https://stackoverflow.com/questions/3558977/android-broadcast-receiver-error-class-not-found-exception

标签

android

exception

broadcastreceiver