Develop Reference

Unable to find explicit activity class exception even if the class is declared in the projects manifest

I transformed my project into a library. This project just displays a blank activity. I imported this library into another project where I want to call it thru the projects main activity but I keep on getting the error below even if I already declared the activity inside the projects manifest.
Unable to find explicit activity class {com.package.name/com.package.name.BatibotActivity}; have you declared this activity in your AndroidManifest.xml?
This is my project manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="pak.paks.pocket" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity android:name=".MainActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.package.name.BatibotActivity"
android:screenOrientation="portrait" >
</activity>
</application>
</manifest>
What am I doing wrong?
edit:
this is my BatibotActivity
package com.package.name;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class BatibotActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_batibot);
}
}
EDIT2
This is the class that is calling the BatibotActivity
package pak.paks.pocket;
import android.content.ComponentName;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void submitBtn(View view) {
Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setComponent(new ComponentName("com.package.name",
"com.package.name.BatibotActivity"));
startActivity(intent);
}
}

By the log message, you are trying to open com.package.name/com.package.name.BatibotActivity, but the Activity registered on AndroidManifest.xml is pak.paks.pocket/com.package.name.BatibotActivity.
The first parameter for ComponentName is the package name. This is the correct code:
Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setComponent(new ComponentName("pak.paks.pocket", "com.package.name.BatibotActivity"));
startActivity(intent);

Please check your manifest tag's package attr.
<manifest package="com.package.name">
<application>
...
</application>
</manifest>

Unfortunately [yourapp], has stopped

I'm using intent method to make a simple app that takes you from main screen [with an enter button] to another screen which has three options. Code sourced online and seems to be error free, though my app crashes saying "Unfortunately [yourapp], has stopped" immediately after i press the button which is meant to take to the the other screen.
This is my first activity code:
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
}
public void addListenerOnButton() {
final Context context = this;
button = (Button) findViewById(R.id.enterBtn);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent intent = new Intent(context, HomeActivity.class);
startActivity(intent);
}
});
}
}`
And this is my landing screen's activity code:
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
public class HomeActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
}
}
I'm really stuck with this issue and any help would be much appreciated. Many thanks in advance.

Every activity needs to be added in your manifest file under application tag. This seems to be the problem in your case.

Try to post you LogCat so that we might get some more information and if you have not yet added your Activity in the manifest, this is the way of adding it (Activities go under application tag)
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.southmp3"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".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=".HomeActivity"
android:label="#string/app_name" >
</activity>
</application>
all the Activities should be going under the application tag

I had forgotten to register my new activity on the androidmanifest.xml file. That's what sorted my app crash issue.

Android Application Crashing

I'm trying to make my application start another class.
What im trying to learn is how to get another class to run in the background - like if the user opens the application, the application stays running.
I thought if I could try to open another class by using an intent, it would work. When i run my application on the emulator, it just crashes...
Here is the opening:
package omg.justry;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
public class MainActivity extends Activity {
#Override
//super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
public void onCreate(Bundle savedInstanceState) {
Intent openStartingPoint = new Intent("omg.justtry.PartF**king2");
startActivity(openStartingPoint);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
Here is the "PartF**king2" class:
package omg.justry;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.widget.Toast;
public class PartF**king2 extends Activity{
public void onCreate(Bundle savedInstanceState) {
Context context = getApplicationContext();
CharSequence text = "Hello toast!";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
}
The thing is, Eclipse doesn't show any errors. I just exported the app and installed it to the emulator using adb.
I also added the class to the AndroidManifest as you see here:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="omg.justry"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="PartF**king2"></activity>
</application>
I think its the manifest now that I look at it but whatever i do, it gets an error or crashes with Eclipse not explaining anything.

In every class, you onCreate(Bundle savedInstanceState) method MUST contain
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
The super is absolutly mandatory, and the setContentView defines the layout for your activity.
And an Activity cannot "run in the background". Start by reading some Android tutorial, and you'll have some clues about what to do.

Cannot load new blank activity - android tutorial

I am a new android developer and encountered a problem while following the tutorial on Android's site - http://developer.android.com/training/basics/firstapp/starting-activity.html
My program loads on the emulator fine, but when you type something into the EditText and then hit the send button, a window pops up saying "App has stopped working". It seems as though my new activity isn't being created and I'm not sure as to why. I've scoured the web (and my code) to see if I could get a solution but did so to no avail. Any help would be appreciated.
The code for my first activity:
package com.example.appli;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myapp.MESSAGE";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.testlayout);
//////Button myButton = (Button) findViewById(R.id.my_button); //Told in tutorial to put this in onCreate
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
/** Called when the user selects the Send button */
public void sendMessage(View view) {
// Do something in response to button
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
The code for my second activity (the one being called)
package com.example.appli;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
public class DisplayMessageActivity extends Activity{
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//get message from intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
setContentView(textView);
}
}
The Manifest
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.appli"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity android:name="com.example.myapp.DisplayMessageActivity" />
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

In AndroidManifest File you have declared incorrect package
change
<activity android:name="com.example.myapp.DisplayMessageActivity" />
to
<activity android:name="com.example.appli.DisplayMessageActivity" />
or just
<activity android:name=".DisplayMessageActivity" />

you have declared only one Activity that's also wrong package name
already your manifest has the package name
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.appli"
so just declare like this
<activity android:name=".DisplayMessageActivity" />
and you need to add this in your manifest also
<activity android:name=".MainActivity />
remove the target SDK version that you mentioned
android:targetSdkVersion="15"

Try this
<activity android:name=".DisplayMessageActivity"/>
Instead of
<activity android:name="com.example.myapp.DisplayMessageActivity" />
in your Manifest.xml file.

You has defined the package package com.example.appli; in your activities.
Why have you defined you activity in manifest like <activity android:name="com.example.myapp.DisplayMessageActivity" />?
Replace this line with
<activity android:name=".DisplayMessageActivity" />.

Android execution error in AVD

an anyone look at this simple code (?) and tell me what's wrong please?
I'm a complete beginner to android development and I don't understand why my application doesn't even start. I get an unexpected error.. : (
Here it is:
package applicationTest.ppr.com;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
public class MainClass extends Activity {
/** Called when the activity is first created. */
/*Global vars*/
public static LinearLayout lila;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
lila = (LinearLayout) findViewById(R.id.lilay);
setContentView(lila);
}
public void Shortoast(){new Game(this);}
public static LinearLayout returnLayout(){return lila;}
}
The program doesn't even launch, and I think it might have something to do with how I handle the LinearLayout and setContentView();
anyway thanks very much in advance!

Suggestion: keep it as simple as possible until you fix the issue!
Then you can concentrate on your business logic.
package applicationTest.ppr.com;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
public class MainClass extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.id.lilay);
}
}
Also, is your main activity mapped in the Android manifest?
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name="MainClass"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</activity>
--EDIT--
Do you have the lilay.xml file in your res/layout folder?