Develop Reference

Banner ad not showing after app store application update

Initially, my application was showing ads but recently I have updated my application on play store after which it is not showing banner ads most of the times but Interstitial ads are being shown.
After checking the logcat it shows "Ad failed to load : 3" which normally occurs initially when you release your apps/ads initially.
Below is the code:
AdView adView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
adView.loadAd(adRequest);
<com.google.android.gms.ads.AdView
xmlns:ads="http://schemas.android.com/apk/res-auto"
android:id="#+id/adView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
ads:adSize="SMART_BANNER"
ads:adUnitId="#string/first_banner"></com.google.android.gms.ads.AdView>

The ad request was successful, but no ad was returned due to lack of ad inventory.
There is nothing wrong with your code , the issue is admob doesnt always have Ad to return for your request possible reasons could be
-you have just registered your publisher id as it takes some time to start serving ads
-you have filtered some ads
Kindly refer this doc: https://developers.google.com/android/reference/com/google/android/gms/ads/AdRequest#ERROR_CODE_NO_FILL

Ad Mob ads not showing regularly

I'm testing the ad mobs ads on a real device. Sometimes the ads shows up and sometimes it doesn't shows. I've no idea what the problem is.
While testing on a virtual device I used test ads and they always shows up but now I'am using real ads on a device with real app-id and unit-id.
Below is the code I'm using. Any help would be highly appreciated.
Java Code:
MobileAds.initialize(this,"ca-app-pub-8665656565286300~4683225285");
mAdview = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
mAdview.loadAd(adRequest);
XML:
<com.google.android.gms.ads.AdView
xmlns:ads="http://schemas.android.com/apk/res-auto"
android:id="#+id/adView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_alignParentBottom="true"
ads:adSize="BANNER"
ads:adUnitId="ca-app-pub-8665656565286300/8888341401"
/>

ADMOB: Ad is showing on Emulator but not on real device

So, I tried inserting an ad in my app. The test ad is visible on emulator but not on the real device. This question may seem like duplicate but it isn't. I have looked many questions regarding that but they aren't relevant to me. I seem to get everything right on emulator but not on real device. Then I debugged the app on my moto G4 and still no ad.
On my activity:
MobileAds.initialize(this, "ca-app-pub-4408797825766729~9067984003");
AdView mAdView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
mAdView.loadAd(adRequest);
On the layout xml:
<com.google.android.gms.ads.AdView
android:id="#+id/adView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
ads:adSize="LARGE_BANNER"
ads:adUnitId="ca-app-pub-4408797825766729/5546529636" />
other than this I didn't code anything related to ads.

If you Have created/added new app on admob it will take time to show ads on your app.
and make sure you have this permission
<uses-permission android:name="android.permission.INTERNET" />

Admob test ad working but not real ad

I added everything to android application as per the instructions from the admob website. On both the emulator and phone i tested my app. The test ads were displaying properly. i generated a signed apk and still it is showing the test ads. what should i do?
here my code:
<com.google.android.gms.ads.AdView
android:id="#+id/adView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_alignParentBottom="true"
ads:adSize="BANNER"
ads:adUnitId="#string/banner_ad_unit_id">
</com.google.android.gms.ads.AdView>
in MainActivity:
MobileAds.initialize(getApplicationContext(), "ca-app-pub-9815982880222619/9339487889");
mAdView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
mAdView.loadAd(adRequest);
Please help me!

Android, admob advert is not displaying

I am trying to implement a banner advert in my Android application. I have used Gradle to download the dependencies, etc.
In my activity where I want the advert to be displayed I have:
<com.google.android.gms.ads.AdView
android:id="#+id/ad"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
ads:adSize="BANNER"
ads:adUnitId="#string/ad_mob_id" />
And ad_mob_id is
ca-app-pub-3940256099942544/6300978111
Which is for test ads, I took that from https://developers.google.com/mobile-ads-sdk/docs/admob/android/quick-start#step_1_modify_the_main_activity_layout
However when I run the activity nothing is displayed and there are no errors/warnings generated.
Am I missing another step?

AdView mAdView = (AdView) getView().findViewById(R.id.adView); // locate the id the banner view
// if you do not use fragments and you are using it directing the remove the getView();
AdRequest adRequest = new AdRequest.Builder().build();
mAdView.loadAd(adRequest); // load it..that's all and you will see logs on it
i took it from the link you posted, it has all you need.