检查Android版本。

如果你安装的是非市场应用程序，和不兼容的版本，你会得到这个错误。

应用程序的目标是2.3.4 您的设备是2.2 然后你会得到这个错误。

我也有同样的问题。我不知道即使是测试，应用程序也必须签名。

自签名后，它安装好了。

如果您有该应用程序的以前版本，请先尝试删除它，现在我的问题已通过该方法解决。

尝试在AndroidManifest.xml中进行更改:

设置debuggable为true 签署apk

我也面临着同样的问题。问题是我的AndroidManifest.xml文件中的主要活动写了两次。我删除了副本。

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.