"Android" Android app fails to install and cannot be opened

Here are some of the issues that I personally encountered that the app could not install:

2. Unable to install the app :
   • The phone system version is too low: it does not conform to the minimum version supported by the app. (for example, the app only supports Android 4.0 + phones, and the phone is Android2.3) solution: Change the phone;
   • App already exists but installing the same app again causes the app to not install:
     • The downloaded app version number is lower than the currently installed version of the app. Solution: Check the current installed app version number to download the updated version upgrade;
     • There is not enough space on the phone and there is not enough local storage to cause an error during the application installation decompression. Solution: Clean up your phone trash and free up more space;
     • No permissions are given to install the app. Solution: Settings-security-open an application that installs "unknown source";
   • There is also a residual file of the previous installation package in the mobile system, which prevents the installation from being overwritten when it is installed again. Solution: Apply a full uninstall (after the device is connected to the computer, in debug mode via the command line: ADB uninstall <com.xxx.xxx (package name) > to uninstall the app)
   • (special) Phone native system error, which causes some applications to be installed. Solution: Restore the factory settings, if necessary, double wipe (Shuangqing) to brush the machine;
   • Installation package resolution failed:
     • APK file is corrupted;
     • Installed application requires the minimum version number is higher than the current phone system version;
     • The memory card is not in the correct format or corrupted;
4. App cannot be opened or rolled back:
   • High memory consumption, causing the system to forcibly shut down the application;
   • Application compatibility issues:
     • Problems caused by the compatibility of the class library files referenced in the project's Code;
     • Application of device support for 32-bit and 64-bit architecture CPUs is incomplete (so package supports armabi-v7a);
     • For example, Android WEAR/TV (wearable/TV) applications are likely to support only wear/tv devices, and cross-platform devices (mobile phones) cannot be installed. Solution: Buy a watch and change your phone.

"Android" Android app fails to install and cannot be opened