App closing with clicking on about button

06-04 12:34:07.871 3697-3697/com.example.halls.basicrecipes E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.halls.basicrecipes, PID: 3697 android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.halls.basicrecipes/com.example.halls.basicrecipes.About}; have you declared this activity in your AndroidManifest.xml? at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1805) at android.app.Instrumentation.execStartActivity(Instrumentation.java:1523) at android.app.Activity.startActivityForResult(Activity.java:4224) at android.app.Activity.startActivityForResult(Activity.java:4183) at android.app.Activity.startActivity(Activity.java:4507) at android.app.Activity.startActivity(Activity.java:4475) at com.example.halls.basicrecipes.MainMenu.onClick(MainMenu.java:22) at android.view.View.performClick(View.java:5610) at android.view.View$PerformClick.run(View.java:22265) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

enter code here

here is my code

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.halls.basicrecipes">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainMenu">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>


</manifest>

Solution

Each Activity in your project have to be declared in your Manifest.

So, you have to declare the About activity in your AndroidManifest file like this :

<activity
    android:name=".About"
    android:label="@string/app_name" />