现象：手机uni.chooseImage图片和uni.chooseVideo上传视频资源返回的临时的路劲，把这个临时的路径存储到sqlite数据库中；这个时候如果退出手机杀掉手机app的进程然后重新打开app的时候，调用查询的接口反选图片的时候会出现图片无法显示的问题；视频资源则是正常的。
产生现象的原因：是因为杀掉手机进程的时候上传的img临时文件会丢失掉；
解决的办法：
1.先调用uni.chooseImage方法返回临时的路劲；
uni.chooseImage({
count: 9, //默认9
sizeType: ['original', 'compressed'], //可以指定是原图还是压缩图，默认二者都有
sourceType: [ 'camera' , 'album'], //从相册选择
fileType: 'image',
success: function(res) {
}
})
2.调用pathToBase64的方法将临时的url地址转换成base64的存储在sqlite数据库中；
3.反选数据，使用base64ToPath方法将图片的base64的数据转换成地址；
4.在此过程中，我们把base64存入数据库的之后再取回base64的数据，会出现数据库将+变成了空格和换行；
5.调用正则表达式处理数据 item = item.replace(/\s/g,"+") //将空格转换成+号
附上base64与url质检相互转换的方法：
新建image-tools.js的文件
function getLocalFilePath(path) {
if (path.indexOf('_www') === 0 || path.indexOf('_doc') === 0 || path.indexOf('_documents') === 0 || path.indexOf('_downloads') === 0) {
return path
}
if (path.indexOf('file://') === 0) {
return path
}
if (path.indexOf('/storage/emulated/0/') === 0) {
return path
}
if (path.indexOf('/') === 0) {
var localFilePath = plus.io.convertAbsoluteFileSystem(path)
if (localFilePath !== path) {
return localFilePath
} else {
path = path.substr(1)
}
}
return '_www/' + path
}
function dataUrlToBase64(str) {
var array = str.split(',')
return array[array.length - 1]
}
var index = 0
function getNewFileId() {
return Date.now() + String(index++)
}
function biggerThan(v1, v2) {
var v1Array = v1.split('.')
var v2Array = v2.split('.')
var update = false
for (var index = 0; index < v2Array.length; index++) {
var diff = v1Array[index] - v2Array[index]
if (diff !== 0) {
update = diff > 0
break
}
}
return update
}
export function pathToBase64(path) {
return new Promise(function(resolve, reject) {
if (typeof window === 'object' && 'document' in window) {
if (typeof FileReader === 'function') {
var xhr = new XMLHttpRequest()
xhr.open('GET', path, true)
xhr.responseType = 'blob'
xhr.onload = function() {
if (this.status === 200) {
let fileReader = new FileReader()
fileReader.onload = function(e) {
resolve(e.target.result)
}
fileReader.onerror = reject
fileReader.readAsDataURL(this.response)
}
}
xhr.onerror = reject
xhr.send()
return
}
var canvas = document.createElement('canvas')
var c2x = canvas.getContext('2d')
var img = new Image
img.onload = function() {
canvas.width = img.width
canvas.height = img.height
c2x.drawImage(img, 0, 0)
resolve(canvas.toDataURL())
canvas.height = canvas.width = 0
}
img.onerror = reject
img.src = path
return
}
if (typeof plus === 'object') {
plus.io.resolveLocalFileSystemURL(getLocalFilePath(path), function(entry) {
entry.file(function(file) {
var fileReader = new plus.io.FileReader()
fileReader.onload = function(data) {
resolve(data.target.result)
}
fileReader.onerror = function(error) {
reject(error)
}
fileReader.readAsDataURL(file)
}, function(error) {
reject(error)
})
}, function(error) {
reject(error)
})
return
}
if (typeof wx === 'object' && wx.canIUse('getFileSystemManager')) {
wx.getFileSystemManager().readFile({
filePath: path,
encoding: 'base64',
success: function(res) {
resolve('data:image/png;base64,' + res.data)
},
fail: function(error) {
reject(error)
}
})
return
}
reject(new Error('not support'))
})
}
export function base64ToPath(base64) {
return new Promise(function(resolve, reject) {
if (typeof window === 'object' && 'document' in window) {
base64 = base64.split(',')
var type = base64[0].match(/:(.*?);/)[1]
var str = atob(base64[1])
var n = str.length
var array = new Uint8Array(n)
while (n--) {
array[n] = str.charCodeAt(n)
}
return resolve((window.URL || window.webkitURL).createObjectURL(new Blob([array], {
type: type })))
}
var extName = base64.split(',')[0].match(/data\:\S+\/(\S+);/)
if (extName) {
extName = extName[1]
} else {
reject(new Error('base64 error'))
}
var fileName = getNewFileId() + '.' + extName
if (typeof plus === 'object') {
var basePath = '_doc'
var dirPath = 'uniapp_temp'
var filePath = basePath + '/' + dirPath + '/' + fileName
if (!biggerThan(plus.os.name === 'Android' ? '1.9.9.80627' : '1.9.9.80472', plus.runtime.innerVersion)) {
plus.io.resolveLocalFileSystemURL(basePath, function(entry) {
entry.getDirectory(dirPath, {
create: true,
exclusive: false,
}, function(entry) {
entry.getFile(fileName, {
create: true,
exclusive: false,
}, function(entry) {
entry.createWriter(function(writer) {
writer.onwrite = function() {
resolve(filePath)
}
writer.onerror = reject
writer.seek(0)
writer.writeAsBinary(dataUrlToBase64(base64))
}, reject)
}, reject)
}, reject)
}, reject)
return
}
var bitmap = new plus.nativeObj.Bitmap(fileName)
bitmap.loadBase64Data(base64, function() {
bitmap.save(filePath, {
}, function() {
bitmap.clear()
resolve(filePath)
}, function(error) {
bitmap.clear()
reject(error)
})
}, function(error) {
bitmap.clear()
reject(error)
})
return
}
if (typeof wx === 'object' && wx.canIUse('getFileSystemManager')) {
var filePath = wx.env.USER_DATA_PATH + '/' + fileName
wx.getFileSystemManager().writeFile({
filePath: filePath,
data: dataUrlToBase64(base64),
encoding: 'base64',
success: function() {
resolve(filePath)
},
fail: function(error) {
reject(error)
}
})
return
}
reject(new Error('not support'))
})
}
以上本人亲测有效，可以解决图片资源和video资源保存sqlite数据库的问题，欢迎大家多多指点，有更好的方法可以一起交流