I've tried everything I could think of, but still I cannot run my tests using Robotium.
I set the robotium library and my main project to be exported in the Project configuration as suggested here
I've set the android:debuggable flag to true as suggested here
I also checked the android:targetPackage is set properly in the manifest as suggested here
Also tried to change the scope of the main project dependency when building the test module to Provided instead of Compile (I am not sure what that does...)
Here is the AndroidManifest for the Test project:
<?xml version="1.0" encoding="utf-8"?>
<!-- package name must be unique so suffix with "tests" so package loader doesn't ignore us -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.matthieu.tests"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="4"
android:targetSdkVersion="17" />
<application
android:debuggable="true">
<uses-library android:name="android.test.runner"/>
</application>
<instrumentation android:name="android.test.InstrumentationTestRunner"
android:targetPackage="com.matthieu"
android:label="Tests for com.matthieu"/>
</manifest>
And here is the exception I get:
java.lang.RuntimeException: Exception during suite construction
at android.test.suitebuilder.TestSuiteBuilder$FailedToCreateTests.testSuiteConstructionFailed(TestSuiteBuilder.java:239)
at java.lang.reflect.Method.invokeNative(Native Method)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:169)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:154)
at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:520)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1447)
Caused by: java.lang.reflect.InvocationTargetException
at com.matthieu.MainMenuActivityTest.<init>(MainMenuActivityTest.java:26)
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:446)
at android.test.suitebuilder.TestMethod.instantiateTest(TestMethod.java:87)
at android.test.suitebuilder.TestMethod.createTest(TestMethod.java:73)
at android.test.suitebuilder.TestSuiteBuilder.addTest(TestSuiteBuilder.java:263)
at android.test.suitebuilder.TestSuiteBuilder.build(TestSuiteBuilder.java:185)
at android.test.InstrumentationTestRunner.onCreate(InstrumentationTestRunner.java:373)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4218)
at android.app.ActivityThread.access$3000(ActivityThread.java:125)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2071)
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 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.NoClassDefFoundError: com.matthieu.MainMenuActivity
... 19 more
Note also that I see a few errors like this in the logcat:
01-04 14:44:51.822: WARN/dalvikvm(1263): Class resolved by unexpected DEX: Lcom/matthieu/MainMenuActivity;(0x44e7f980):0x249f70 ref [Lcom/actionbarsherlock/app/SherlockFragmentActivity;] Lcom/actionbarsherlock/app/SherlockFragmentActivity;(0x44e7f980):0x121770
01-04 14:44:51.833: WARN/dalvikvm(1263): (Lcom/matthieu/MainMenuActivity; had used a different Lcom/actionbarsherlock/app/SherlockFragmentActivity; during pre-verification)
01-04 14:44:51.851: WARN/dalvikvm(1263): Unable to resolve superclass of Lcom/matthieu/MainMenuActivity; (644)
01-04 14:44:51.851: WARN/dalvikvm(1263): Link of class 'Lcom/matthieu/MainMenuActivity;' failed
01-04 14:44:51.851: ERROR/dalvikvm(1263): Could not find class 'com.matthieu.MainMenuActivity', referenced from method com.matthieu.MainMenuActivityTest.testFirstTimeAppOpening
01-04 14:44:51.851: WARN/dalvikvm(1263): VFY: unable to resolve check-cast 849 (Lcom/matthieu/MainMenuActivity;) in Lcom/matthieu/MainMenuActivityTest;
If it makes any difference, I am using IntelliJ Idea (11.1.5), SDK 17, SDK Tools 21.0.1 and updated Robotium to 3.6
UPDATE:
Found one related discussion here. I can see different error messages whether I run only one test or all the tests, and my application does use FragmentActivity. But no matter what I do, I am not able to run any test (not one, not all)...
This type of errors occured when you did the below things.
1.If you entered wrong package name for "android:targetPackage" in manifest file.
so please check the target package name in the manifest file.
2.If you add the same library for both android app and test project.
Ambiguity occurs when you add same library for both android app and test project.so please add the library to app project only.
Finally.... I found the only way I could find to make it work there
Do not keep the Robotium test cases in a separate module... no idea why there is no way to make it work, but really I tried everything I could think of or I could find around.
I had this problem for a while and tried many things, what worked for me in the end was simply going into
properties -> Java build path -> Projects
for the test project and then removing the project under test and adding it again. (Since i cannot reproduce the problem and don't remember the details, it may be safest to remove the project under test, then clean both project, and then add the project under test)
I experienced the same problem again (see my other answer on this page) but could not solve the problem with my own solution this time. This time i found another solution: Removing the private libraries for the test project by right clicking on the test project and then
properties -> Java build path -> Libraries
and removing "Android Private Libraries"
PS My answer was inspired by information i found on this page: http://android.foxykeep.com/dev/how-to-fix-the-classdefnotfounderror-with-adt-17
I face same problem. its happen just because of i was trying to test my project with the JUnit instead of Android JUnit test.
so for that make test project right click on it > run as > Android Junit test.
it has work in my case.
best of luck
I am working on application which is host on android market. Sometimes (once a month ) I got a crash report:
Unable to instantiate application java.lang.ClassNotFoundException
App downloads are between 10,000-50,000. I don't know why this exceptions raise on some devices not all ( I tested it on 3 different devices & I couldn't re-produce it at my end).
I read articles/suggestions on different android forums regarding the issue but I didn't succeed in solving it. Does anyone face similar issue & suggest me what should I do?
Note:
I am extending application class like this
public class MyApplication extends Application {
}
I register it in the manifest.xml like this
<application android:icon="#drawable/app_icon"
android:label="#string/my_app_name" android:name="MyApplication">
Stack Trace :
java.lang.RuntimeException: Unable to instantiate application com.xyz.MyApplication java.lang.ClassNotFoundException: com.xyz.MyApplication in loader dalvik.system.PathClassLoader[/mnt/asec/com.xyz-1/pkg.apk]
at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:650)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4238)
at android.app.ActivityThread.access$3000(ActivityThread.java:126)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2076)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4633)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: com.xyz.MyApplication in loader dalvik.system.PathClassLoader[/mnt/asec/com.xyz-1/pkg.apk]
at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
at android.app.Instrumentation.newApplication(Instrumentation.java:942)
at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:645)
I don't know why application crash on some devices not all.
Some other similar questions indicate that this can be a user error. "/mnt/asec/..." indicates that the app is running from the sdcard. If the sdcard is removed it could cause this error. 3rd party apps or rooted devices can probably move an app to the sdcard even if its not allowed by the manifest.
Similar Question
I think the problem is with getApplication() which I have used in 10 different place. So I have used singleton pattern to solve this.
public class MyApplication extends Application {
private static MyApplication me;
#Override
public void onCreate() {
super.onCreate();
me = this ;
}
public static MyApplication getInstance() {
return me;
}
}
Now I have used getApplication() like this
MyApplication application = MyApplication.getInstance();
insted of
MyApplication application = (MyApplication) getApplication();
I have uploaded the fixed version on the market & now waiting if there is anymore this kind of crash. If everything goes perfect ( if no more crash in 2 weeks) then I will close the question. In meanwhile anyone has better idea or know the solution , please share it. Thanks,
In my case, I was compiling and signing with Eclipse ADT (with File > Export > Export Android Application...) but missing some classes if I decompile my .apk.
To solve it I use "Export an unsigned APK" and sign it using jarsigner and zipalign.
android:name=".MyApplication"
also consider adding full package
I have been using robotium to test my android application. I found it very useful tool so far. Recently we have done a refactoring that would use only one activity in the entire application, each page will be replaced by a fragment.
However, After we start using that activity to run the unit tests, the test complains NoClassDefound error -- it couldn't find the activity class. I don't see anywhere I have change the configuration whatsoever.
Can anybody give a clue what might be wrong , where to check and so on ?
[INFO] java.lang.RuntimeException: Exception during suite construction
at android.test.suitebuilder.TestSuiteBuilder$FailedToCreateTests.testSuiteConstructionFailed(T estSuiteBuilder.java:239)
at java.lang.reflect.Method.invokeNative(Native Method)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:169)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:154)
at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:529)
....
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NoClassDefFoundError: com.xxx.wallet.HaloActivity
at com.xxx.wallet.HaloActivityTest.<init>(HaloActivityTest.java:12)
... 18 more
The app apk is loaded, AndroidManifest.xml should be ok too.
Make sureafter refactoring:
The AndroidManifest.xml of the test project is still accurate:
<instrumentation android:targetPackage="package.of.the.app.under.test">
The Test class is still accurate:
public class YourTest extends ActivityInstrumentationTestCase2<SplashScreenActivity> {
protected static final String TARGET_PACKAGE_ID = "package.of.the.app.under.test";
protected Solo solo;
public Test() {
super(TARGET_PACKAGE_ID, StartingActivityOfYourAppUnderTest.class);
}
//..
}
All libraries of the app under test can only (!) be found in libs/yourlibrary.jar and are referenced in Project->Properties->Java Build Path->Libraries
I have a ContentProvider class and is declared in AndroidMenifest.xml like this:
<provider android:name=".MediaSearchProvider"
android:authorities="org.iii.romulus.meridian.mediasearch">
<path-permission android:path="/search_suggest_query"
android:readPermission="android.permission.GLOBAL_SEARCH" />
</provider>
It works well on most devices, but the Market tells me some users are suffering error with it. The stack trace is:
java.lang.RuntimeException: Unable to get provider org.iii.romulus.meridian.MediaSearchProvider: java.lang.ClassNotFoundException: org.iii.romulus.meridian.MediaSearchProvider in loader dalvik.system.PathClassLoader[/mnt/asec/org.iii.romulus.meridian-1/pkg.apk]
at android.app.ActivityThread.installProvider(ActivityThread.java:4509)
at android.app.ActivityThread.installContentProviders(ActivityThread.java:4281)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4237)
at android.app.ActivityThread.access$3000(ActivityThread.java:125)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2071)
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:878)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: org.iii.romulus.meridian.MediaSearchProvider in loader dalvik.system.PathClassLoader[/mnt/asec/org.iii.romulus.meridian-1/pkg.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.installProvider(ActivityThread.java:4494)
... 12 more
I have totally no idea about what's up and I can't reproduce it on any of my phones. I also tried clean and build, but the report still comes up.
Anyone can help? Thanks!
The answers regarding proguard are incorrect. This would cause an easily reproducible error on every phone, every time, because the ContentProvider class would be completely missing. The developer clearly states that they cannot reproduce the error, meaning that the ContentProvider class is present but for some reason is not being found on one of their user's phones.
I have the same crash reported in the market for my app. The stack traces look identical, and the error is occurring at installProvider. I have about 15 test phones in my office and none of them can reproduce this problem. Any other ideas would be appreciated.
Fully qualified names in the manifest are only necessary if your java package names are not the same as your android package name. If a fully qualified name is not specified, the OS will automatically prepend the android package name to the class name specified in the manifest.
Ensure twice that you have correct qualified class name specified in AndroidManifest.xml, it must read something like this:
<provider
android:authorities="org.iii.romulus.meridian.mediasearch"
android:name="org.iii.romulus.meridian.MediaSearchProvider">
</provider>
Notice that #name is fully qualified.
This sounds similar to an issue I had that was caused by an issue with the ClassLoader, see here: Bizarre behaviour when using Apache Commons lib in Android
This bug discusses an error relating to the class loader failing sometimes. The fix for me was to add this line:
Thread.currentThread().setContextClassLoader(this.getClassLoader());
in the constructor of the class that was calling the code that was failing.
Proguard excludes all inherited content providers by default with this line (make sure it's in your cfg):
-keep public class * extends android.content.ContentProvider
If you have any additional inheritance you should exclude it as well or exclude your specific Content Provider class, for example:
-keep public class org.iii.romulus.meridian.MediaSearchProvider
This is an old thread, and the OP didn't have the same ContentProvider declaration as me, but I had the same exact error, so I want to share my findings, in case it helps anyone.
For me, what caused the problem was that the ContentProvider declaration in the AndroidManifest.xml had an exported attribute set to true:
android:exported="true"
Removing it fixed the problem for me. (I didn't really need it)
If your app has grown large enough to require Multidexing and your app is not set up correctly as a Multidex app you will get this error. To set up your app as a multidex app, follow these directions:
Setup multidex app
I was trying to run a sample code
While launching the application in the android 1.5 emulator , I got these errors....
Any one have some hint..?
ERROR from LogCat:
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): FATAL EXCEPTION: main
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.s.android.test/com.s.android.test.MainActivity}: java.lang.ClassNotFoundException: com.s.android.test.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.s.android.test-2.apk]
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1544)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1638)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:928)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.os.Handler.dispatchMessage(Handler.java:99)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.os.Looper.loop(Looper.java:123)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.ActivityThread.main(ActivityThread.java:3647)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at java.lang.reflect.Method.invokeNative(Native Method)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at java.lang.reflect.Method.invoke(Method.java:507)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at dalvik.system.NativeStart.main(Native Method)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): Caused by: java.lang.ClassNotFoundException: com.s.android.test.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.s.android.test-2.apk]
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1536)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): ... 11 more
01-13 02:28:08.407: WARN/ActivityManager(112): Force finishing activity com.s.android.test/.MainActivity
Edit
This error happens to most of the beginners, the thing is that you have to add all your activities in the Manifest file.
It is a problem of your Intent.
Please add your Activity in your AndroidManifest.xml.
When you want to make a new activity, you should register it in your AndroidManifest.xml.
You may be trying to find the view before onCreate() which is incorrect.
public class MainActivity extends Activity {
ImageView mainImage = (ImageView) findViewById(R.id.imageViewMain); //incorrect
#Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
...
}
There is another way to get an java.lang.RuntimeException: Unable to instantiate activity ComponentInfo exception and that is the activity that you are trying to start is abstract. I made this stupid mistake once and its very easy to overlook.
In my case I forgot to add the google maps library
<application>
....
<uses-library android:name="com.google.android.maps" />
</application>
Also, check that you're not missing the preceding dot before the activity path
<activity android:name=".activities.MainActivity"/>
It also happens because of this issue. I unchecked the jars that needed be exported to the apk and this same thing happened. Please tick the jars that your app Needs to run.
This might not be relevant to the actual question, but in my instance, I tried to implement Kotlin and left out apply plugin: 'kotlin-android'. The error happened because it could not recognize the MainActivity in as a .kt file.
Hope it helps someone.
I encountered this problem too, but in a slightly different way. Here was my scenario:
App detail:
Using ActionBarSherlock as a library
Using android-support-v4-r7-googlemaps.jar in the ActionBarSherlock library so I could use a "map fragment" in my primary project
Added the jar to the build path of my primary project
Included the <uses-library android:name="com.google.android.maps" /> in the manifests of both the library project and my primary project (this may not be necessary in the library?)
The manifest in the primary project had the proper activity definition and all of the appropriate properties
I didn't have an abstract activity or any of the other gotchas I've seen on Stack Overflow pertaining to this problem.
However, I still encountered the error described in the original post and could not get it to go away. The problem though, was slightly different in one regard:
It only affected a fresh install of the application to my device. Any time the app installed for the first time, I would get the error preceded by several "warnings" of: Unable to resolve superclass of FragmentActivity
Those warnings traced back to the ActionBarSherlock library
The app would force close and crash.
If I immediately rebuilt and redeployed the app, it worked fine.
The only time it crashed was on a totally fresh install. If I uninstalled the app, built and deployed again from Eclipse, it would crash. Build/deploy a second time, it would work fine.
How I fixed it:
In the ActionBarSherlock library project, I added the android-support-v4-r7-googlemaps.jar to the build path
This step alone did not fix the problem
Once the jar was added to the build path, I had change the order on the Java Build Path > Order and Export tab - I set the JAR to the first item in the list (it was the last after the /src and /gen items).
I then rebuilt and redeployed the app to my device - it worked as expected on a fresh install. Just to be certain, I uninstalled it again 2-3 times and reinstalled - still worked as expected.
This may be a total rookie mistake, but I spent quite a while digging through posts and my code to figure it out, so hopefully it can be helpful to someone else. May not fix all situations, but in this particular case, that ended up being the solution to my problem.
This error can also be the ultimate sign of a dumb mistake (like when I - I mean, cough, like when a friend of mine who showed me their code once) where they try to execute code outside of a method like trying to do this:
SQLiteDatabase db = openOrCreateDatabase("DB", MODE_PRIVATE, null); //trying to perform function where you can only set up objects, primitives, etc
#Override
public void onCreate(Bundle savedInstanceState) {
....
}
rather than this:
SQLiteDatabase db;
#Override
public void onCreate(Bundle savedInstanceState) {
db = openOrCreateDatabase("DB", MODE_PRIVATE, null);
....
}
For me, my package string in AndroidManifest.xml was incorrect (copied from a tutorial).
Make sure the package string in this file is the same as where your main activity is, e.g.
package="com.example.app"
An easy way to do this is to open the AndroidManifest.xml file in the "Manifest" tab, and type it in the text box next to Package, or use the Browse button.
Also, the package string for my activity was wrong, e.g.
<activity android:name="com.example.app.MainActivity" android:label="#string/app_name">
I (stupidly) got the same error weeks later when I renamed my package name. If you do this, make sure you update the AndroidManifest.xml file too.
I got rid of this problem by deleting the Bin and Gen folder from project(which automatically come back when the project will build) and then cleaning the project from ->Menu -> Project -> clean.
Thanks.
Simply Clean your working project or restart eclipse. Then run your project. it will work.
In my case I haven't set the setContentView(R.layout.main);
If you create a new class do not foget to set this in on onCreate(Bundle savedInstanceState) method.
I have done this stupid mistake several times.
For me it was different from any of the above,
The activity was declared as abstract, That is why giving the error.
Once it removed it worked.
Earlier
public abstract class SampleActivity extends AppcompatActivity{
}
After removal
public class SampleActivity extends AppcompatActivity{
}
Ok, I am fairly experienced on the iPhone but new to android. I got this issue when I had:
Button infoButton = (Button)findViewById(R.id.InfoButton);
this line of code above:
#Override
public void onCreate (Bundle savedInstanceState) {
}
May be I am sleep deprived :P
In my case, I was trying to initialize the components(UI) even before the onCreate is called for the Activity.
Make sure your UI components are initialized/linked in the onCreate method after setContentView
NB: This is my first mistake while learning Android programming.
I recently encountered this with fresh re-install of Eclipse. Turns out my Compiler compliance level was set to Java 1.7 and project required 1.6.
In Eclipse:
Project -> Properties -> Java Compiler -> JDK Compliance
Whow are there lots of ways to get this error!.
I will add another given none of the others either applied or were the cause.
I forgot the 'public' in the declaration of my activity class! It was package private.
I had been writing so much Bluetooth code that habit caused me to create an activity class that was package private.
Says something about the obscurity of this error message.
Make sure MainActivity is not "abstract".
abstract class MainActivity : AppCompatActivity()
just remove the abstract
class MainActivity : AppCompatActivity() {
Got this problem, and fixed it by setting the "launch mode" property of the activity.
Another reason of this problem may be a missing library.
Go to Properties -> Android and check that you add the libraries correctly
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...).
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"
As suggested by djjeck in comment in this answer I missed to put public modifier for my class.
It should be
public class MyActivity extends AppCompatActivity {
It may help some like me.
In my case I forget to make MainActivity class as public.
Other solutions:
Add activity in Manifest file
Verify all access modifiers
This happens to me fairly frequently when using the NDK. I found that it is necessary for me to do a "Clean" in Eclipse after every time I do a ndk-build. Hope it helps anyone :)
This error also occurs when you use of ActionBarActivity but assigned a non AppCompat style.
To fix this just set your apps style parent to an Theme.AppCompat one like this.:
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light">
<!-- Customize your theme here. -->
</style>
Right click on project > properties > android > and try with different version of the android earlier i was doing with android 4.4 then i changed to android 4.3 and it worked !
Most the time If Activity name changed reflected all over the project except the AndroidManifest.xml file.
You just need to Add the name in manifest manually.
<activity
android:name="Activity_Class_Name"
android:label="#string/app_name">
</activity>
I had the same issue (Unable to instantiate Activity) :
FIRST reason :
I was accessing
Camera mCamera;
Camera.Parameters params = mCamera.getParameters();
before
mCamera = Camera.open();
So right way of doing is, open the camera first and then access parameters.
SECOND reason : Declare your activity in the manifest file
<activity android:name=".activities.MainActivity"/>
THIRD reason :
Declare Camera permission in your manifest file.
<uses-feature android:name="android.hardware.Camera"></uses-feature>
<uses-permission android:name="android.permission.CAMERA" />
Hope this helps
In my case, I was trying to embed the Facebook SDK and I was having the wrong Application ID; thus the error was popping up. In your manifest file, you should have the proper meta data:
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="#string/facebook_app_id" />