For android library projects, is meaningful in manifest?

Question

It\'s all pretty much in the title. Although I see specified in all the example library project\'s AndroidManifest.xml I\'ve seen

Answer 1

As per the documentation, It says for

The attribute android:minSdkVersion is surely required and if you don't pass any then it will take 1 meaning - App will support all api versions of android and then you will have to make your app support all of them if you dont pass any statically.

Caution: If you do not declare this attribute, the system assumes a default value of "1", which indicates that your application is compatible with all versions of Android. If your application is not compatible with all versions (for instance, it uses APIs introduced in API Level 3) and you have not declared the proper minSdkVersion, then when installed on a system with an API Level less than 3, the application will crash during runtime when attempting to access the unavailable APIs. For this reason, be certain to declare the appropriate API Level in the minSdkVersion attribute.

The attribute android:maxSdkVersion is little bit tricky to understand..doc says,

Warning: Declaring this attribute is not recommended. First, there is no need to set the attribute as means of blocking deployment of your application onto new versions of the Android platform as they are released. By design, new versions of the platform are fully backward-compatible. Your application should work properly on new versions, provided it uses only standard APIs and follows development best practices. Second, note that in some cases, declaring the attribute can result in your application being removed from users' devices after a system update to a higher API Level. Most devices on which your application is likely to be installed will receive periodic system updates over the air, so you should consider their effect on your application before setting this attribute.

And,

Future versions of Android (beyond Android 2.0.1) will no longer check or enforce the maxSdkVersion attribute during installation or re-validation. Google Play will continue to use the attribute as a filter, however, when presenting users with applications available for download.

That warning is to indicate Negative points that can happen if you declare that attributes But as you look into other side If you are developing anything that supports some specific Android Version then The ATTRIBUTE is most useful to you.

The step taken to remove that attribute is to encourage developer to make their app supportive to all different(newer) version.

Only if you developing with the version 2.0.1^ then you can say Its not needed to write that but If you write that Google paly will use that as filter for presenting user

So My Conclusion and Advice

use the element with atleast one attribute android:minSdkVersion