Error running 'app' Default Activity not found

Question

学习安卓过程，哈，运行遇到Error running 'app' Default Activity not found， 怎么解决？

Answer 1

打开androidmanifest.xml,设置主activity,

<activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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