Hi Yang,
Please note that Assets and Media are completely different and not related to each other in any way. They both store similar kinds of information, but they are not interchangeable, and using one in place of other will always result in blank data. The asset resource is for managing assets for asset-based ads. The media is for upload/get media to be used in ads. For creating/managing App Campaigns, you will need to use the
asset resource to add any ad group ad assets. Please refer to
this guide for more information.
Other ad types that do not have assets will use MediaFile. For example, Gmail ads and Image ads. You may find
this documentation helpful to locate as to which ad types support MediaFile.
Let me know if you have any questions.
Thanks,
Bharani, Google Ads API Team
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