Typescript navCtrl.push在Ionic3中不工作
我正在用Ionic制作一个应用程序,将图像上传到我的Firebase存储中。上传完成后,应用程序应将用户重定向到Welcome页面。上载正在工作,但由于某些原因,用户没有被重定向。看看代码的结尾:控制台确实显示了Typescript navCtrl.push在Ionic3中不工作,typescript,firebase,ionic-framework,firebase-storage,ionic3,Typescript,Firebase,Ionic Framework,Firebase Storage,Ionic3,我正在用Ionic制作一个应用程序,将图像上传到我的Firebase存储中。上传完成后,应用程序应将用户重定向到Welcome页面。上载正在工作,但由于某些原因,用户没有被重定向。看看代码的结尾:控制台确实显示了上传的,但是这个.navCtrl.push(WelcomePage)不起作用 upload() { let storageRef = firebase.storage().ref(); const filename = "profilePic"; const imageR
上传的
,但是这个.navCtrl.push(WelcomePage)
不起作用
upload() {
let storageRef = firebase.storage().ref();
const filename = "profilePic";
const imageRef = storageRef.child(`images/${filename}.jpg`).putString(this.profilepicture, firebase.storage.StringFormat.DATA_URL);
imageRef.on('state_changed', function(snapshot){
var progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
document.getElementById("percent").innerHTML = "Progresso:" + Math.floor(progress) + "%";
console.log('Upload is ' + progress + '% done');
switch (snapshot.state) {
case firebase.storage.TaskState.PAUSED:
console.log('Upload is paused');
break;
case firebase.storage.TaskState.RUNNING:
console.log('Upload is running');
break;
}
}, function(error) {
// Handle unsuccessful uploads
}, function() {
// Handle successful uploads on complete
console.log('Uploaded');
this.navCtrl.push(WelcomePage);
});
}
在回调中,
此
的含义很可能不同。如果是这种情况,可以将navCtrl
放在单独的变量中,也可以使用胖箭头函数
将navCtrl
放在单独的变量中
此
的含义取决于您在中使用它的功能。由于回调是独立的函数,因此它们对this
也有自己的值。因此在回调中,this.navCtrl
不存在
解决方案是在回调之前将所需的值捕获到唯一的变量名中:
var navCtlr = this.navCtrl;
imageRef.on('state_changed', function(snapshot){
var progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
document.getElementById("percent").innerHTML = "Progresso:" + Math.floor(progress) + "%";
console.log('Upload is ' + progress + '% done');
switch (snapshot.state) {
case firebase.storage.TaskState.PAUSED:
console.log('Upload is paused');
break;
case firebase.storage.TaskState.RUNNING:
console.log('Upload is running');
break;
}
}, function(error) {
// Handle unsuccessful uploads
}, function() {
// Handle successful uploads on complete
console.log('Uploaded');
navCtrl.push(WelcomePage);
});
使用胖箭头函数
ES6添加了一种使用胖箭头表示法定义回调函数的新方法。在代码函数(error)中,{
可以替换为(error)=>{
。除了稍微短一点之外,新符号实际上在回调中保留了this
的含义。因此:
imageRef.on('state_changed', (snapshot) => {
var progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
document.getElementById("percent").innerHTML = "Progresso:" + Math.floor(progress) + "%";
console.log('Upload is ' + progress + '% done');
switch (snapshot.state) {
case firebase.storage.TaskState.PAUSED:
console.log('Upload is paused');
break;
case firebase.storage.TaskState.RUNNING:
console.log('Upload is running');
break;
}
},(error) => {
// Handle unsuccessful uploads
}, () => {
// Handle successful uploads on complete
console.log('Uploaded');
this.navCtrl.push(WelcomePage);
});
解决了!非常感谢您不是一个而是两个非常好地解释了的解决方案!!!!