安装时候碰到的一个问题：已经签名的包，重新通过adb install 会提示安装错误。提示：Failure [INSTALL_FAILED_ALREADY_EXISTS]
为啥eclipse自己就可以不停滴覆盖重装呢？
因为eclipse自动打包是debug的签名，而我打如果是release签名就会出现上面的报错。
解决办法：adb install -r
adb install的相关参数
adb install [-l] [-r] [-d] [-s] [--algo <algorithm name> --key <hex-encoded key> --iv <hex-encoded iv>] <file> - push this package file to the device and install it
('-l' means forward-lock the app)
('-r' means reinstall the app, keeping its data)
('-d' means allow version code downgrade)
('-s' means install on SD card instead of internal storage)
('--algo', '--key', and '--iv' mean the file is encrypted already)
adb install -r 这里的r是reinstall 的缩写
adb install -r (reinstall) 重装
adb install -s (sdcard) 装在SD卡上而不是internal storage
adb uninstall -k (keep) 保留用户数据。
