解决adb install 错误INSTALL_FAILED_UPDATE_INCOMPATIBLE

adb install 一个apk，报错INSTALL_FAILED_UPDATE_INCOMPATIBEL，

在android源码里搜索字串" INSTALL_FAILED_UPDATE_INCOMPATIBLE "

$ grep -r INSTALL_FAILED_UPDATE_INCOMPATIBLE frameworks/base/

frameworks/base/core/java/android/content/pm/PackageManager.java:    public static final int INSTALL_FAILED_UPDATE_INCOMPATIBLE = -7;

frameworks/base/core/java/android/content/pm/PackageManager.java:            case INSTALL_FAILED_UPDATE_INCOMPATIBLE: return "INSTALL_FAILED_UPDATE_INCOMPATIBLE";

frameworks/base/core/java/android/content/pm/PackageManager.java:            case INSTALL_FAILED_UPDATE_INCOMPATIBLE: return PackageInstaller.STATUS_FAILURE_CONFLICT;

打开文件：frameworks/base/core/java/android/content/pm/PackageManager.java

    /**

     * Installation return code: this is passed to the

     * {@link IPackageInstallObserver} if a previously installed package of the

     * same name has a different signature than the new package (and the old

     * package's data was not removed).

     *

     * @hide

     */

    @SystemApi

    public static final int INSTALL_FAILED_UPDATE_INCOMPATIBLE = -7;

即如果你要安装的新apk，在设备上已经存在了，并且之前安装的apk和新安装的apk，其签名是不一样的,

则会报这个错。

解决方法：把原来的apk卸载干净，再安装新apk。