英文:
Flutter ImagePicker - Getting image asynchronously in onPressed shows lint warning
问题
我正在实现一个使用ImagePicker上传个人资料图片的功能，并将逻辑放入按钮的onPressed函数中，代码如下：
OutlinedButton.icon(
icon: Icon(Icons.upload),
label: Text("选择个人资料图片"),
onPressed: () async {
XFile? image = await introVM.imagePicker.pickImage(
source: ImageSource.gallery,
imageQuality: 50,
preferredCameraDevice: CameraDevice.front);
if (image != null) introVM.setProfilePicture(image.path);
},
);
一切都正常，没有错误，但我收到了一个关于async部分的lint警告：
预期是同步函数，但是得到了异步函数。
我做错了吗？
英文:
I am implementing a profile picture upload with ImagePicker and put the logic into the onPressed function of a button like this:
OutlinedButton.icon(
icon: Icon(Icons.upload),
label: Text("Select profile picture"),
onPressed: () async {
XFile? image = await introVM.imagePicker.pickImage(
source: ImageSource.gallery,
imageQuality: 50,
preferredCameraDevice: CameraDevice.front);
if (image != null) introVM.setProfilePicture(image!.path);
},
);
Everything works fine without errors, but I am getting a lint warning about the async part:
> Expected a sync function but got async.
Am I doing it wrong?
答案1
得分: 2
根据Dart Code Metrics，这是对Dart代码设计的警告，该设计避免在期望同步调用的地方调用异步函数。
避免在同步期望时传递异步函数。
为了避免linting的投诉，目前有两种方法。
- 使用then()方法
OutlinedButton.icon(
icon: Icon(Icons.upload),
label: Text("选择个人资料图片"),
onPressed: () {
introVM.imagePicker.pickImage(
source: ImageSource.gallery,
imageQuality: 50,
preferredCameraDevice: CameraDevice.front
).then((XFile? xFile) {
if (xFile != null) introVM.setProfilePicture(xFile!.path);
});
},
);
- 使用匿名函数（我不推荐这种方式，我们应该将其转换为单独的函数）
OutlinedButton.icon(
icon: Icon(Icons.upload),
label: Text("选择个人资料图片"),
onPressed: () {
// 应该移到单独的函数
() async {
XFile? image = await introVM.imagePicker.pickImage(
source: ImageSource.gallery,
imageQuality: 50,
preferredCameraDevice: CameraDevice.front);
if (image != null) introVM.setProfilePicture(image!.path);
};
},
);
英文:
According to Dart Code Metrics, it is a warning for a Dart code design that avoids calling an asynchronous function where a synchronous is expected.
avoid-passing-async-when-sync-expected
To avoid complaints from linting, there are 2 ways for now.
- use then() method
OutlinedButton.icon(
icon: Icon(Icons.upload),
label: Text("Select profile picture"),
onPressed: () {
introVM.imagePicker.pickImage(
source: ImageSource.gallery,
imageQuality: 50,
preferredCameraDevice: CameraDevice.front
).then((XFile? xFile) {
if (xFile != null) introVM.setProfilePicture(xFile!.path);
});
},
);
- Use the anonymous function (I am not preferred that one, and we should convert it into a separate function)
OutlinedButton.icon(
icon: Icon(Icons.upload),
label: Text("Select profile picture"),
onPressed: () {
// Should move to a separate function
() async {
XFile? image = await introVM.imagePicker.pickImage(
source: ImageSource.gallery,
imageQuality: 50,
preferredCameraDevice: CameraDevice.front);
if (image != null) introVM.setProfilePicture(image!.path);
};
},
);
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