Android 判断当前应用是否开启消息通知（支持9.0）

我就偷懒了，直接贴代码了

这个我写在MainActivity的onCreate()里面的，相当于进入主页面检查一下

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            //判断是否需要开启通知栏功能
            NotificationUtil.OpenNotificationSetting(mContext, new NotificationUtil.OnNextLitener() {
                @Override
                public void onNext() {
                    Toast.makeText(mContext,"已开启通知权限",Toast.LENGTH_SHORT).show();
                }
            });
        }

然后是工具类

/**
 * Created by Muzik
 * 2018/12/20 10:17
 */
public class NotificationUtil {
    //判断是否需要打开设置界面
    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public static void OpenNotificationSetting(Context context, OnNextLitener mOnNextLitener) {
        if (!isNotificationEnabled(context)) {
            showSettingDialog(context);
        } else {
            if (mOnNextLitener != null) {
                mOnNextLitener.onNext();
            }
        }
    }

    //判断该app是否打开了通知
    /**
     * 可以通过NotificationManagerCompat 中的 areNotificationsEnabled()来判断是否开启通知权限。NotificationManagerCompat 在 android.support.v4.app包中，是API 22.1.0 中加入的。而 areNotificationsEnabled()则是在 API 24.1.0之后加入的。
     * areNotificationsEnabled 只对 API 19 及以上版本有效，低于API 19 会一直返回true
     * */
    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public static boolean isNotificationEnabled(Context context) {
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){
            NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(context);
            boolean areNotificationsEnabled = notificationManagerCompat.areNotificationsEnabled();
            return areNotificationsEnabled;
        }

        String CHECK_OP_NO_THROW = "checkOpNoThrow";
        String OP_POST_NOTIFICATION = "OP_POST_NOTIFICATION";

        AppOpsManager mAppOps = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
        ApplicationInfo appInfo = context.getApplicationInfo();
        String pkg = context.getApplicationContext().getPackageName();
        int uid = appInfo.uid;

        Class appOpsClass = null;
        /* Context.APP_OPS_MANAGER */
        try {
            appOpsClass = Class.forName(AppOpsManager.class.getName());
            Method checkOpNoThrowMethod = appOpsClass.getMethod(CHECK_OP_NO_THROW, Integer.TYPE, Integer.TYPE,
                    String.class);
            Field opPostNotificationValue = appOpsClass.getDeclaredField(OP_POST_NOTIFICATION);

            int value = (Integer) opPostNotificationValue.get(Integer.class);
            return ((Integer) checkOpNoThrowMethod.invoke(mAppOps, value, uid, pkg) == AppOpsManager.MODE_ALLOWED);

        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;

    }

    //打开手机设置页面
    /**
     * 假设没有开启通知权限，点击之后就需要跳转到 APP的通知设置界面，对应的Action是：Settings.ACTION_APP_NOTIFICATION_SETTINGS, 这个Action是 API 26 后增加的
     * 如果在部分手机中无法精确的跳转到 APP对应的通知设置界面，那么我们就考虑直接跳转到 APP信息界面，对应的Action是：Settings.ACTION_APPLICATION_DETAILS_SETTINGS*/
    private static void gotoSet(Context context) {

        Intent intent = new Intent();
        if (Build.VERSION.SDK_INT >= 26) {
            // android 8.0引导
            intent.setAction("android.settings.APP_NOTIFICATION_SETTINGS");
            intent.putExtra("android.provider.extra.APP_PACKAGE", context.getPackageName());
        } else if (Build.VERSION.SDK_INT >= 21) {
            // android 5.0-7.0
            intent.setAction("android.settings.APP_NOTIFICATION_SETTINGS");
            intent.putExtra("app_package", context.getPackageName());
            intent.putExtra("app_uid", context.getApplicationInfo().uid);
        } else {
            // 其他
            intent.setAction("android.settings.APPLICATION_DETAILS_SETTINGS");
            intent.setData(Uri.fromParts("package", context.getPackageName(), null));
        }
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
    }

    /*=====================添加Listener回调================================*/
    public interface OnNextLitener {
        /**
         * 不需要设置通知的下一步
         */
        void onNext();
    }

    private OnNextLitener mOnNextLitener;

    public void setOnNextLitener(OnNextLitener mOnNextLitener) {
        this.mOnNextLitener = mOnNextLitener;
    }



    public static void showSettingDialog(final Context mContext) {
        //提示弹窗
        final CustomDialogSureCancel customDialogSureCancel = new CustomDialogSureCancel(mContext);
        customDialogSureCancel.getTitleView().setVisibility(View.GONE);
        customDialogSureCancel.getContentView().setText(R.string.never_be_pass);
        customDialogSureCancel.getSureView().setText(R.string.i_know);
        customDialogSureCancel.getCancelView().setText(R.string.go_to_set);
        customDialogSureCancel.getSureView().setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                customDialogSureCancel.cancel();

            }
        });
        customDialogSureCancel.getCancelView().setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                customDialogSureCancel.cancel();
                gotoSet(mContext);

            }
        });
        customDialogSureCancel.show();
    }
}

这里面有个自定义的showSettingDialog，就是个对话框，我就不贴了哈~