The uniapp WeChat applet realizes the function of saving base64 pictures in the album and forwarding and sharing with WeChat friends, and the record can be used directly in cv! ! ! !

1. The function of saving base64 pictures in the album

Prompt api: that.$refs.uToast.show uses the toast of uview2.0, which can be replaced according to the imported ui library;

saveBase64ImageToPhotosAlbum() {
				let that = this
				var timestamp = new Date().getTime();
				let base64 = this.userInfo.jumpAddFriendQr.replace(/^data:image\/\w+;BASE64,/, ""); //去掉data:image/png;base64,
				let filePath = wx.env.USER_DATA_PATH + `/addFriends_${timestamp}_qrcode.png`;
				uni.showLoading({
					title: '保存中',
					mask: true
				})
				uni.getFileSystemManager().writeFile({
					filePath: filePath, //创建一个临时文件名
					data: base64, //写入的文本或二进制数据
					encoding: 'base64', //写入当前文件的字符编码
					success: res => {
						uni.saveImageToPhotosAlbum({
							filePath: filePath,
							success: function(res2) {
								uni.hideLoading();
								that.$refs.uToast.show({
									type: 'success',
									message: "保存成功~",
									duration: 1200,
								})
							},
							fail: function(err) {
								uni.hideLoading();
								console.log(err.errMsg);
								that.$refs.uToast.show({
									type: 'error',
									message: `保存失败`,
									duration: 1200,
								})
							}
						})
					},
					fail: err => {
						uni.hideLoading();
						console.log(err)
						that.$refs.uToast.show({
							type: 'error',
							message: `创建文件失败`,
							duration: 1200,
						})
					}
				})
			},
			saveQRcodeFn() {//保存图片到相册按钮的点击事件函数
				let that = this
				uni.getSetting({
					success(res) {
						console.log(res);
						if (!res.authSetting['scope.writePhotosAlbum']) {
							uni.authorize({
								scope: 'scope.writePhotosAlbum',
								success(res) {
									that.saveBase64ImageToPhotosAlbum()
								},
								fail() {
									uni.showModal({
										content: '请允许相册权限,拒绝将无法正常保存图片',
										showCancel: false,
										success() {
											uni.openSetting({
												success(settingdata) {
													if (settingdata.authSetting['scope.writePhotosAlbum']) {} else {
														console.log('获取权限失败')
														that.$refs.uToast.show({
															type: 'error',
															message: `获取权限失败`,
															duration: 1200,
														})
													}
												}
											})
										}
									})
								}
							})
						} else {
							that.saveBase64ImageToPhotosAlbum()
						}
					}
				})
			},

2. Forward and share base64 pictures to WeChat friends 

This function will always report an error when debugging in the WeChat developer tool. The real device is fine, and it may be a bug in the compiler.

sharePic() {//分享图片给好友按钮的点击事件函数
				let that = this
				this.base64ToFilePath(this.userInfo.jumpAddFriendQr, (filePath) => {
					console.log(filePath);
					wx.showShareImageMenu({ //分享给朋友
						path: filePath,
						success: (res) => {
							console.log("分享成功：", res);
						},
						fail: (err) => {
							console.log("分享取消：", err);
						},
					})
				})
			},
			base64ToFilePath(base64data, fun) {//封装的base64转换成临时文件路径的函数
				const base64 = base64data; //base64格式图片
				const time = new Date().getTime();
				const imgPath = wx.env.USER_DATA_PATH + "/addFriends" + time + "share_qrcode" + ".png"; //去掉data:image/png;base64,如果图片字符串不含要清空的前缀,可以不执行下行代码.
				const imageData = base64.replace(/^data:image\/\w+;base64,/, "");
				const file = wx.getFileSystemManager();
				file.writeFileSync(imgPath, imageData, "base64");
				fun(imgPath);
			},