Android 8.0不能自动安装APK问题的解决方法（完美适配）

<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
  boolean hasInstallPermission = isHasInstallPermissionWithO(context);
  if (!hasInstallPermission) {
   startInstallPermissionSettingActivity(context);
     return;
  }
}

@RequiresApi (api = Build.VERSION_CODES.O)
private boolean isHasInstallPermissionWithO(Context context){
 if (context == null){
  return false;
 }
 return context.getPackageManager().canRequestPackageInstalls();
}

/**
 * 开启设置安装未知来源应用权限界面
 * @param context
 */
@RequiresApi (api = Build.VERSION_CODES.O)
private void startInstallPermissionSettingActivity(Context context) {
 if (context == null){
  return;
 }
 Intent intent = new Intent(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES);
 ((Activity)context).startActivityForResult(intent,REQUEST_CODE_APP_INSTALL);
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
  super.onActivityResult(requestCode, resultCode, data)
  if (resultCode== Activity.RESULT_OK ){
   when(requestCode){
    REQUEST_CODE_APP_INSTALL -> {
     onSettingCheckUpdate()
    }
   }
  }
 }