为什么我在android中的活动出错？

Question

I declare both of my activity class in AndroidManifest.xml file them when I run my application it stop unfortunately with this error message:-

 android.content.ActivityNotFoundException: Unable to find explicit activity class {com.androidtutorialpoint.androidobservablescrollview/com.androidtutorialpoint.androidobservablescrollview.ParallaxToolbarScrollViewActivity}; have you declared this activity in your AndroidManifest.xml?

This is my manifest file:-

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

    <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"
            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=".ParallaxToolbarScrollViewActivity"
            android:label="@string/title_activity_parallaxtoolbarscrollview"
            android:theme="@style/AppTheme.Toolbar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="com.androidtutorialpoint.androidobservablescrollview" />
            </intent-filter>
        </activity>

    </application>

</manifest>

My Activity class names are:-

1. MainActivity
2. ParallaxToolbarScrollViewActivity

Answer 1

You placed it in the wrong location it should be inside the application tag. All your <activity... /> tags should be placed under the <application.. /> tag.

Hope this helps!

Answer 2

Clean your build and rebuild the project. If you are using instance run android studio feature then disable this for avoid this problem

Answer 3

Remove

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

                <category android:name="com.androidtutorialpoint.androidobservablescrollview" />
            </intent-filter>

otherwise change your package name insted of

com.androidtutorialpoint.androidobservablescrollview

Answer 4

Remove intent-filter tag from your second activity.

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

    <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"
            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=".ParallaxToolbarScrollViewActivity"
            android:label="@string/title_activity_parallaxtoolbarscrollview"
            android:theme="@style/AppTheme.Toolbar">
        </activity>

    </application>

</manifest>

Answer 5

Put intent filter to single activity which you want to start first. If launching activity is MainActivity, then remove intent filter from ParallaxToolbarScrollViewActivity. Or recheck the category line **

"com.androidtutorialpoint.androidobservablescrollview"

**

<activity
        android:name=".ParallaxToolbarScrollViewActivity"
        android:label="@string/title_activity_parallaxtoolbarscrollview"
        android:theme="@style/AppTheme.Toolbar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="com.androidtutorialpoint.androidobservablescrollview" />
        </intent-filter>
    </activity>