动画高度属性 [英] Animating height property

问题描述

你好，有stackoverflow和nativescript用户！

Hello there stackoverflow and nativescript users!

我对动画设置视图有疑问.

I have a problem with animating a view.

我想要的是:我正在尝试创建一个可以单击的视图，它会在动画下方打开一个新视图，将所有其他视图向下推.

What I want: I am trying to create a view where you can click and it opens op a new view below animated pushing all other views further down.

问题:只有其中的元素是动画的，什么都不是动画的 完全没有.

Problem: Only the elements inside are animated or nothing is animated at all.

我尝试的方法:我尝试使用原生UI动画，但由于高度过高而没有成功属性不受支持.

What I tried: I tried using the nativescript UI Animations but without success because the height property is not supported.

我的版本: https://gyazo.com/130c2b3467656bcc104c9b8e2c860d94

我很想听听大家提出的解决方案.

I would love to hear the solutions you all have come up with to tackle this.

推荐答案

您可以在本机脚本应用程序中使用tweenjs，定义依赖于tweenjs的以下类(使用npm i @tweenjs/tween.js安装)

You can use tweenjs in your nativescript application defining the following class which rely on tweenjs (install it with npm i @tweenjs/tween.js)

import * as TWEEN from '@tweenjs/tween.js';
export { Easing } from '@tweenjs/tween.js';

TWEEN.now = function () {
    return new Date().getTime();
};

export class Animation extends TWEEN.Tween {
    constructor(obj) {
        super(obj);
        this['_onCompleteCallback'] = function() {
            cancelAnimationFrame();
        };
    }
    start(time) {
        startAnimationFrame();
        return super.start(time);
    }
}

let animationFrameRunning = false;
const cancelAnimationFrame = function() {
    runningTweens--;
    if (animationFrameRunning && runningTweens === 0) {
        animationFrameRunning = false;
    }
};

let runningTweens = 0;
const startAnimationFrame = function() {
    runningTweens++;
    if (!animationFrameRunning) {
        animationFrameRunning = true;
        tAnimate();
    }
};
const requestAnimationFrame = function(cb) {
    return setTimeout(cb, 1000 / 60);
};
function tAnimate() {
    if (animationFrameRunning) {
        requestAnimationFrame(tAnimate);
        TWEEN.update();
    }
}

然后，要设置视图的高度动画，您可以使用这种方法(此方法在nativescript-vue中有效，但是您只需调整检索视图对象的方式即可):

Then, to animate the height of a view you can use a method like this (this one works in nativescript-vue but you just have to adapt the way you retrieve your view object) :

import {Animation, Easing} from "./Animation"

toggle() {
    let view = this.$refs.panel.nativeView
    if (this.showPanel) {
        new Animation({ height: this.fixedHeight })
            .to({ height: 0 }, 500)
            .easing(Easing.Back.In)
            .onUpdate(obj => {
                view.originY = 0
                view.scaleY = obj.height / this.fixedHeight;
                view.height = obj.height;
            })
            .start()
            .onComplete(() => this.showPanel = !this.showPanel);
    } else {
        this.showPanel = !this.showPanel
        new Animation({ height: 0 })
            .to({ height: this.fixedHeight }, 500)
            .easing(Easing.Back.Out)
            .onUpdate(obj => {
                view.originY = 0
                view.scaleY = obj.height / this.fixedHeight;
                view.height = obj.height;
            })
            .start();
    }
}

在此处进行了讨论: https://github.com/NativeScript/NativeScript/issues/1764 我主要改进了onUpdate使其具有流畅的动画

This was discussed here : https://github.com/NativeScript/NativeScript/issues/1764 I mainly improved the onUpdate to have a smooth animation

这篇关于动画高度属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！