android.intent.action.EXTERNAL_APPLICATIONS_AVAILABLE

String android.content.Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE = "android.intent.action.EXTERNAL_APPLICATIONS_AVAILABLE"

Broadcast Action: Resources for a set of packages (which were previously unavailable) are currently available since the media on which they exist is available. The extra data EXTRA_CHANGED_PACKAGE_LIST contains a list of packages whose availability changed. The extra data EXTRA_CHANGED_UID_LIST contains a list of uids of packages whose availability changed. Note that the packages in this list do not receive this broadcast. The specified set of packages are now available on the system.

Includes the following extras:

    * EXTRA_CHANGED_PACKAGE_LIST is the set of packages whose resources(were previously unavailable) are currently available. EXTRA_CHANGED_UID_LIST is the set of uids of the packages whose resources(were previously unavailable) are currently available.

This is a protected intent that can only be sent by the system

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这个action从2.2版开始支持

当SD卡从不可用到可用且SD卡中之前安装有应用，则系统发出这个广播，
注意从SD卡中新加入的应用不会接收到这个广播。
这个广播的intent中包括如下数据：
1.从SD卡中新加入的应用包名
2.从SD卡中新加入的应用ID

这种广播只能由系统发出。