[Flutter/dart]initialization error of Admob

Phenomenon

When Admob is added in the app and the app is started, the following error occurs.

java.lang.RuntimeException: Unable to get provider com.google.android.gms.ads.MobileAdsInitProvider

Cause

AndroidManifest was written incorrectly.

<meta-data> must be in the same hierarchy as activity.

correct

<activity
    android:name=".MainActivity">
    ...
<meta-data
    android:name="com.google.android.gms.ads.APPLICATION_ID"
    android:value="ca-app-pub-***~***"/>

incorrect

    <activity
        android:name=".MainActivity">
    ...
<meta-data
    android:name="com.google.android.gms.ads.APPLICATION_ID"
    android:value="ca-app-pub-***~***"/>