uses-feature之android:required

android:required

Boolean value that indicates whether the application requires the feature specified in android:name.

• When you declare android:required="true" for a feature, you are specifying that the application cannot function, or is not designed to function, when the specified feature is not present on the device.
• When you declare android:required="false" for a feature, it means that the application prefers to use the feature if present on the device, but that it is designed to function without the specified feature, if necessary.

The default value for android:required if not declared is "true".