java.lang.RuntimeException：无法实例化活动ComponentInfo / ClassNotFoundException

Question

I'm develop android application and than i wanna additional new Activity i had error on my logcat

My LogCat:

04-19 12:59:17.654: D/AndroidRuntime(18135): Shutting down VM
04-19 12:59:17.654: W/dalvikvm(18135): threadid=1: thread exiting with uncaught exception (group=0x4001d878)
04-19 12:59:17.684: E/AndroidRuntime(18135): FATAL EXCEPTION: main
04-19 12:59:17.684: E/AndroidRuntime(18135): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.bvblogic.android.batterypower/com.bvblogic.android.batterypower.activities.UnlockActivity}: java.lang.ClassNotFoundException: com.bvblogic.android.batterypower.activities.UnlockActivity in loader dalvik.system.PathClassLoader[/data/app/com.bvblogic.android.batterypower-1.apk]
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2587)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2681)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.os.Looper.loop(Looper.java:123)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.ActivityThread.main(ActivityThread.java:4640)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at java.lang.reflect.Method.invokeNative(Native Method)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at java.lang.reflect.Method.invoke(Method.java:521)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at dalvik.system.NativeStart.main(Native Method)
04-19 12:59:17.684: E/AndroidRuntime(18135): Caused by: java.lang.ClassNotFoundException: com.bvblogic.android.batterypower.activities.UnlockActivity in loader dalvik.system.PathClassLoader[/data/app/com.bvblogic.android.batterypower-1.apk]
04-19 12:59:17.684: E/AndroidRuntime(18135):    at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
04-19 12:59:17.684: E/AndroidRuntime(18135):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2579)
04-19 12:59:17.684: E/AndroidRuntime(18135):    ... 11 more

My manifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.bvblogic.android.batterypower"
    android:versionCode="1"
    android:versionName="1.0" >

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

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.BATTERY_STATS" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.UPDATE_DEVICE_STATS" />
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.WRITE_SETTINGS" />
    <uses-permission android:name="android.permission.HARDWARE_TEST" />
    <uses-permission android:name="android.permission.RESTART_PACKAGES" />
    <uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />
    <uses-permission android:name="android.permission.GET_PACKAGE_SIZE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity android:name=".activities.UnlockActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="com.bvblogic.android.batterypower.activities.BatteryPowerTabActivity" >
        </activity>
        <activity android:name="com.bvblogic.android.batterypower.activities.MonitoringActivity" >
        </activity>
        <activity android:name="com.bvblogic.android.batterypower.activities.SettingsActivity" >
        </activity>
        <activity android:name="com.bvblogic.android.batterypower.activities.ProcessManagerActivity" >
        </activity>
        <activity
            android:name="com.bvblogic.android.batterypower.activities.DummyBrightnessActivity"
            android:excludeFromRecents="true"
            android:taskAffinity="com.bvblogic.android.batterypower.Dummy"
            android:theme="@android:style/Theme.Translucent.NoTitleBar" >
        </activity>

        <service android:name="com.bvblogic.android.batterypower.util.TurboBoost" >
        </service>
        <service android:name="com.bvblogic.android.batterypower.services.BatteryPowerService" />

        <receiver
            android:name="com.bvblogic.android.batterypower.alarm.RegistrationAlarm"
            android:process=":registration" >
        </receiver>
        <receiver
            android:name="com.bvblogic.android.batterypower.alarm.OnlinePingAlarm"
            android:process=":ping" >
        </receiver>
        <receiver
            android:name="com.bvblogic.android.batterypower.alarm.AdNotificationAlarm"
            android:process=":remote" >
        </receiver>
        <receiver
            android:name="com.bvblogic.android.batterypower.widget.MWidgetProvider"
            android:icon="@drawable/btn_remove"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
            </intent-filter>

            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/widget_provider" />
        </receiver>
    </application>

</manifest>

My Activity:

package com.bvblogic.android.batterypower.activities;

import com.bvblogic.android.batterypower.R;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class UnlockActivity extends Activity {  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.settings_auto_saving_layout);
    }
}

Then i'm assigned intent-filter to BatteryPowerTabActivity application started fine. Please help me. Thanks

Answer 1

When upgrading, the 'Order and Export' of the new 'Android Private Libraries' is not always checked. And the android-support-v4.jar is now in this 'Android Private Libraries' section.

To fix this, go to 'Order and Export' and check 'Android Private Libraries'. Then refresh/clean/rebuild.

After you done this 'fix' for a library project, you may need to just close and re-open any depending project, because they may not see this 'fix' immediately.

Answer 2

change your activity declaration in the manifest file into

 <activity android:name=".UnlockActivity">

or else

<activity android:name="Yourcompletepackagename.UnlockActivity">

and try

Answer 3

Dude, this also happened to me when my app was already published in the marketplace. It was a total disaster. I realized it after 5 hours of already publishing it.

There was no problem by running it with the ADT. Problem was with the generated APK. So if you publish an app, test the installation of the pure APK in your test phone.

As you, I also think that problem was with the the update of my ADT, in my case v22.

The solution was to clean and build the project:

Android java.lang.RuntimeException: Unable to instantiate activity ComponentInfo

Answer 4

This can happen if your activity class is inside a default package. I fixed it by moving the activity class to a new package. and changing the manifest.xml

before

activity android:name=".MainActivity"

after

activity android:name="new_package.MainActivity"

Answer 5

I had the same problem, but I had my activity declared in the Manifest file, with the correct name.

My problem was that I didn't have to imported a third party libraries in a "libs" folder, and I needed reference them in my proyect (Right-click, properties, Java Build Path, Libraries, Add Jar...).

About how do you declare an activity in the manifest file, is correct use .ActivityName always that activity be in the main package.

Answer 6

I agree with what @codercat has advised you to do, but this error also comes when you are using v7 and also v13 in the same project structure for different functionalities. Therefore, i advice you to copy the v13 jar file into the libs folder (DO NOT import it as an external jar) and then check the android libraries and android dependencies . Refresh you project and then clean your project. I am sure the error you are facing will go away.

Answer 7

我也有同样的问题，我只是自动关闭构建并手动构建我的android项目，并清理了为我解决此错误的项目

Answer 8

change line from

<activity android:name=".activities.UnlockActivity">  

to

<activity android:name=".com.bvblogic.android.batterypower.activities.UnlockActivity
 ">

Answer 9

Cleaning the project worked for me. You might ask me what led to the issue? LOL I tried to upgrade a project to android 5 from 4.4 and then changed my mind and tried to restore it back to kitkat, then voila! this error came up.

Answer 10

you might have declared String a = edt.getText().toString(); or int 5/3 hence such errors use to come

so,
declare them in onCreate method error will resolved

Answer 11

I solve this problem by remove package name( com.blogspot.geekonjava ) from AndroidManifest.xml like :

<activity
            android:name="com.blogspot.geekonjava.MainActivity"
            android:theme="@style/Theme.AppCompat.Light"
            android:label="@string/app_name" >

to

<activity
            android:name=".MainActivity"
            android:theme="@style/Theme.AppCompat.Light"
            android:label="@string/app_name" >

It work for me hope it works for you.