6.0相机动态权限

 if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA) !=
                PackageManager.PERMISSION_GRANTED) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("温馨提示")
                    .setMessage("为了您更好的使用扫描功能，请您赋予相机权限")
                    .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                        @TargetApi(Build.VERSION_CODES.M)
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            requestPermissions(new String[]{Manifest.permission.CAMERA}, 1);
                        }
                    })
                    .show();

        } else {
            
        }