主要针对老款手机

我只是在试图在我的手机上安装一个运行在4.4.2(又名奇巧)上的apk时遇到了应用程序未安装错误，但我的朋友在他的手机上运行在6+上时没有遇到这个错误。我尝试了其他解决方案，比如删除旧的/调试版本的应用程序(因为apk是一个发布版本)，清除调试应用程序的数据，甚至清除我所有的缓存数据。然后，最后我意识到我所要做的就是在构建我的签名apk时选择两个签名版本。

之前我只选择了V2(完整的APK签名)，但在选择V1 Jar签名之后，我能够成功地在4.4.2设备上安装我签名的APK。

我也面临着同样的问题。 在我的应用程序中有服务。 即使在应用程序卸载后，服务仍在后台运行，在执行应用程序强制停止后，收到应用程序已卸载的消息。 然后我安装了应用程序，没有任何问题。

对我来说，在Android 9 (API 28)上，从播放商店应用程序中禁用谷歌播放保护起作用了，我能够摆脱应用程序未安装的错误。

禁用谷歌播放保护功能。打开“Play Store”应用=>点击 on菜单按钮=> select "Play Protect"选项=>禁用选项 “扫描设备安全威胁”。

您也可能会遇到此问题，因为您的设备制造商没有授权谷歌商业应用程序，如Play Store, YouTube，谷歌地图等。按照这个答案来解决问题。

Clearly there are many causes of this problem. For me the situation was this: I had deployed to my nexus 7 (actual device) from within the Android Studio (v1.3.2). All worked fine. I then created a signed apk and uploaded to my Google Drive. After disconnecting my nexus from the usb, I went to the settings/apps and uninstalled my app (App1). I then opened google drive and clicked on my App1.apk and chose to install it (need to ensure you have allowed installation of apks in settings). Then I got the dreaded message "App not Installed"

Solution for me: go back into settings/apps and scroll though all apps and at the bottom was a pale version of my App1 (note the original App1 was at the top in Alphabetical order which was deleted as above). When clicking on the pale version it said "Not installed for this user". (I had set up my nexus to have more than one user). But in the top right corner there is a three dot button. I pressed this and it said "Uninstall for all users". Which I did and it fixed the problem. I was now able to click on App1.apk and it installed fine without the error.

在我的情况下，我已经声明我的发射器活动为android:exported="false"

<activity android:name=".MainActivity"
            android:exported="false">

我最近瞄准了android 12，不得不把android:exported属性放在我的manifest组件中，但不知道该把什么作为值。将值更改为android:exported="true"有效。