checkSelfPermission 檢查權限失效

摘要: Android M運行targetSdkVersion < 23的應用時，調用checkSelfPermission，不管用戶是否取消授權，checkSelfPermission的返回值始終爲PERMISSION_GRANTED的解決辦法

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.

轉自：[海闊天空玩世不恭的博客](https://my.oschina.net/u/990728/blog/549914)https://my.oschina.net/u/990728/blog/549914

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