我使用firebase上传使用相机或照片库拍摄的图像。承诺包含相关代码：
fileEntry.file(function (file) {
//var reader = new FileReader();
var reader = new FileReader();
reader.onload = (e) => {
var dataURL = reader.result;
let image : string = 'profile_' + self.username + '_' + square + '.jpg',
storageRef : any,
parseUpload : any;
return new Promise((resolve, reject) => {
storageRef = firebase.storage().ref('/profile/' + self.username + '/' + image);
parseUpload = storageRef.putString(dataURL, 'data_url');
parseUpload.on('state_changed', (_snapshot) => {
// We could log the progress here IF necessary
console.log('snapshot progess ' + _snapshot);
},
(_err) => {
reject(_err);
console.log(_err);
},
(success) => {
resolve(parseUpload.snapshot);
})
}).then(value => {
//this.af.list('/profile/' + self.username).push({ pic: image });
}).catch(function(error) {
console.log(error.message);
});
此代码从firebase返回到调用cameraservice的页面控制器中的下载URL：
presentActionSheet() {
let actionSheet = this.actionSheetCtrl.create({
title: 'Choose source',
buttons: [
{
text: 'Camera',
handler: () => {
let itemArrayTwo = this.profComponents.toArray();
this.cameraService.getMedia(this.optionsGetCamera, this.square).then(() => {
let storageRef = firebase.storage().ref().child('/profile/' + this.username + '/profile_' + this.username + '_' + this.square + '.jpg');
storageRef.getDownloadURL().then(url => {
console.log(url);
this.myrenderer.setElementAttribute(itemArrayTwo[this.square - 1].nativeElement, 'src', url);
this.showSquare();
});
}); //pass in square choice
//this.myrenderer.setElementAttribute(this.itemArrayTwo[this.square - 1].nativeElement, 'src', 'block');
console.log('camera clicked');
}
...
问题是，返回下载URL的函数在parseUpload.on('state_ ...完成上传之前运行。控制台输出示例：
...
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log:
https://firebasestorage.googleapis.com/v0/b/mane-4152c.appspot.com/o/profile%2Fjackson%2Fprofile_jackson_1.jpg?alt=media&token=85884da1-d9f1-4ffb-a4dd-a24ce9bdfbef
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
[16:24:16] console.log: snapshot progess [object Object]
...
您可以看到在快照上载进度中记录了downloadURL。在做其他任何事情之前，必须等待firebase上传完成。