在Android的UI线程操作过程中显示ProgressDialog [英] Showing ProgressDialog during UI Thread operation in Android

问题描述

在我asken已经将另一个问题这里似乎PackageManager.getInstalledPackages（ ）不与线程发挥好。由于CommonsWare说明<一个href=\"http://stackoverflow.com/questions/3455781/packagemanager-getinstalledpackages-returns-empty-list\">HERE:

As I've asken on another question HERE it seems that the PackageManager.getInstalledPackages() doesn't play nice with Threading. As CommonsWare stated HERE:

或许软件包管理系统需要在主应用程序被调用
  螺纹，由于某种原因

Perhaps the PackageManager needs to be invoked on the main application thread, for some reason

因此​​，有它在一个线程得到意外的行为，并进入我的活动退出了几下，使显示的应用列表有时物品，有时是空的。在UI线程拥有一切就像一个梦，加载罚款每次。问题是，用户期望某种形式的反馈，我需要提供一个。当我开始活动时，屏幕保持黑色3-4-5-6秒（根据所安装的设备和应用程序上）。我怎么能提供某种反馈？我想到一个ProgressDialog的，但我不知道我怎么可以启动它。谢谢你。

So having it on a thread gets undesired behavior, entering and exiting a few times in my Activity makes the list of displayed apps sometimes with items, sometimes empty. Having everything in the UI Thread works like a dream, loads fine everytime. The thing is, the user expects some sort of feedback and I need to provide one. As I start the activity, the screen remains black for 3-4-5-6 seconds (depending on the device and apps installed). How can I provide some sort of feedback ? I am thinking of a ProgressDialog but I don't know how can I start it. Thank you.

推荐答案

如发现，在循环通过应用工作需要一段时间（其可以在一个单独的线程来实现），相比于呼叫到PackageManager.getInstalledPackages（） （这必须要在UI线程上完成）。

As discovered, the loop to work through the applications takes awhile (which can be done in a separate thread), compared to the call to PackageManager.getInstalledPackages() (which has to be done on the UI thread).

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