Android 调用checkSelfPermission，不管用户是否取消授权，checkSelfPermission的返回值始终为PERMISSION_GRANTED的解决办法

Android M运行targetSdkVersion < 23的应用时，调用checkSelfPermission，不管用户是否取消授权，checkSelfPermission的返回值始终为PERMISSION_GRANTED的解决办法

1. If your application is targeting an API level before 23 (Android M) then both:ContextCompat#checkSelfPermission and Context#checkSelfPermission doesn't work and always returns 0 (PERMISSION_GRANTED). Even if you run the application on Android 6.0 (API 23).

2. It's not fully true that if you targeting an API level before 23 then  you don't have to take care of permissions. If you targeting an API level before 23 then:

   • Android < 6.0: Everything will be ok.

   • Android 6.0: Application's run-time permissions will be granted by default (compatibility mode applies), but the user can change run-time permissions in Android Settings, then you may have a problem.

3. As I said in the 1st point, if you targeting an API level before 23 on Android 6.0 then ContextCompat#checkSelfPermission and Context#checkSelfPermission doesn't work. Fortunately you can use PermissionChecker#checkSelfPermission to check run-time permissions.

Example code:

 public boolean selfPermissionGranted(String permission) {        // For Android < Android M, self permissions are always granted.        boolean result = true;        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {            if (targetSdkVersion >= Build.VERSION_CODES.M) {                // targetSdkVersion >= Android M, we can                // use Context#checkSelfPermission                result = context.checkSelfPermission(permission)                        == PackageManager.PERMISSION_GRANTED;            } else {                // targetSdkVersion < Android M, we have to use PermissionChecker                result = PermissionChecker.checkSelfPermission(context, permission)                        == PermissionChecker.PERMISSION_GRANTED;            }        }        return result;    }

In order to obtain target Sdk Version you can use:

 try {        final PackageInfo info = context.getPackageManager().getPackageInfo(                context.getPackageName(), 0);        targetSdkVersion = info.applicationInfo.targetSdkVersion;    } catch (PackageManager.NameNotFoundException e) {        e.printStackTrace();    }

It works on Nexus 5 with Android M.