多个权限：

private String[] permissions = {Manifest.permission.CAMERA, Manifest.permission.READ_EXTERNAL_STORAGE};
    private List<String> permissionList = new ArrayList<>();


    private void getPermission() {
        if (permissionList != null) {
            permissionList.clear();
        }
        //版本判断。当手机系统大于 23 时，才有必要去判断权限是否获取
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            //权限是否已经 授权 GRANTED---授权  DINIED---拒绝
            for (String permission : permissions) {
                if (ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED) {
                    permissionList.add(permission);
                }
            }

            if(!permissionList.isEmpty()){
                ActivityCompat.requestPermissions(this, permissionList.toArray(new String[permissionList.size()]), 1000);
            }else{
                //表示全都授权了
                getPic();
            }
        }
    }

//权限回调
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == 1000) {
            //权限请求失败
            if(grantResults.length > 0){
                //存放没授权的权限
                List<String> deniedPermissions = new ArrayList<>();
                for(int i = 0; i < grantResults.length; i++){
                    int grantResult = grantResults[i];
                    String permission = permissions[i];
                    if(grantResult != PackageManager.PERMISSION_GRANTED){
                        deniedPermissions.add(permission);
                    }
                }
                if(deniedPermissions.isEmpty()){
                    //说明都授权了
                    getPic();
                } else {
                    //默认false 第二次提醒会有是否不在询问按钮，选择则为true  不在提醒是否申请权限
                    if (!shouldShowRequestPermissionRationale(deniedPermissions.get(0))) {
                        permissionDialog();
                    }
                }
            }
        }
}

    private void permissionDialog() {
        MyAlertDialog permissionDialog = new MyAlertDialog(this);
        permissionDialog.setContentText("需要相机和读写权限，是否去设置？");
        permissionDialog.setCustomDialogListener(new MyDialogClickListener() {
            @Override
            public void clickRight(Dialog dialog, Object data) {
                //允许
                goToAppSetting();
            }

            @Override
            public void clickLeft(Dialog dialog, Object data) {
                //拒绝
            }
        });
    }

注意：小米手机在跳转去申请权限的时候会出现，给了权限但是依然无法使用的问题，请进入系统权限设置才可生效

如果是MIUI12，则需要进入隐私保护，在里面找到需要设置的app，授权权限才可

原因是因为跳转的权限是小于系统权限的，跳转设置权限并不包含系统权限，也就是系统权限大于和包含跳转权限。

不知道是bug还是小米故意为之

    private void goToAppSetting() {
        Intent intent = new Intent();
        intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
        Uri uri = Uri.fromParts("package", getPackageName(), null);
        intent.setData(uri);
        startActivityForResult(intent, 123);
    }

    private void goPhotoAlbum() {
        Intent intent = new Intent();
        intent.setAction(Intent.ACTION_PICK);
        intent.setType("image/*");
        startActivityForResult(intent, 2);
    }


    public void startCamera(){
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(intent, 3);
    }

单个权限申请：单个权限