How UniApp implements image uploading and cropping

UniApp is a cross-platform application development framework based on Vue.js, which can quickly develop applications for both iOS and Android platforms. In UniApp, uploading and cropping images is a common requirement. This article will introduce how to implement image uploading and cropping in UniApp, and provide corresponding code examples.

1. How to implement image upload:

1. Use the uni.uploadFile() method to upload images. First, you need to specify the upload URL, temporary path of the file, file name and other parameters in the uni.uploadFile() method. An example is as follows:

uni.chooseImage({
count: 1,
success: function (res) {

uni.uploadFile({
  url: 'https://example.com/upload',
  filePath: res.tempFilePaths[0],
  name: 'file',
  success: function (res) {
    console.log('图片上传成功', res);
  },
  fail: function (res) {
    console.log('图片上传失败', res);
  }
});

}
});

2. Receive and save uploaded images on the server side. The server side can use various back-end languages ​​(such as Node.js, PHP, Java, etc.) to write corresponding interfaces to receive and save uploaded images. For example, using Node.js and the Express framework, you can write the following interface:

const express = require('express');
const multer = require('multer');

const app = express();
const upload = multer({ dest: 'uploads/' });

app.post('/upload', upload.single('file' ), (req, res) => {
console.log('Picture saved', req.file);
res.send('Picture uploaded successfully');
});

app.listen(3000, () => {
console.log('Server has started');
});

2. How to implement image cropping :

1. Use third-party image cropping plug-in such as image-cropper. First, install the image-cropper plugin in the UniApp project. It can be installed through the npm command or in the plug-in market. After the installation is complete, introduce the image-cropper component into the page where you need to use the image cropping function:

<image-cropper :src="imageSrc" @crop="cropImage"></image-cropper>
<button @click="uploadCroppedImage">上传裁剪后的图片</button>

> ;

<script><br>import imageCropper from '@/components/image-cropper'</script>

export default {
components: {

imageCropper

},
data() {

return {
  imageSrc: ''
}

},
methods: {

uploadCroppedImage(imageData) {
  uni.uploadFile({
    url: 'https://example.com/upload',
    filePath: imageData,
    name: 'file',
    success: function (res) {
      console.log('图片上传成功', res);
    },
    fail: function (res) {
      console.log('图片上传失败', res);
    }
  });
},
cropImage(tempFilePath) {
  this.imageSrc = tempFilePath;
}

}
}

2. Write a backend interface to receive and save the cropped image.

As mentioned above, write the corresponding interface on the server side to receive and save the cropped image.

The above is how to upload and crop images in UniApp. By using the uni.uploadFile() method to upload images, and then using the corresponding back-end interface to receive and save images, the image upload function can be implemented. Using a third-party image cropping plug-in, you can easily implement the image cropping function and upload the image to the server after cropping. I hope this article can be helpful to UniApp developers.

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