微信小程序开发小结

作者: ByteStefan | 来源:发表于2019-02-02 23:01 被阅读0次

声明我是一名安卓开发，最近公司开始搞小程序，所以也学习了一下，感觉不是特别困难。虽然之前大学中也学过 html 和 css，但是好久没有用到基本上全忘记了。。。所以该文章仅限小白查看，帮助更快上手。如果之后再开发中有什么新鲜的东西（对我而言），我会一直在该文章中更新。
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去除 button 边框

.btn-alerts-share::after {
  border: none;
}
注意：如果 button 背景透明，直接设置 background-color: transparent；千万不要用 plain="true"，否则上面代码失效！

本地图片转 base64 / 设置本地图片为背景图

var imgBase64 = wx.getFileSystemManager().readFileSync("pages/img/xxxx.png", "base64")
 注意：通过上面方式可以直接转换并不能得出 base64 图片，还需要在前面进行拼接："data:image/png;base64,"+imgBase64

获取某个节点（控件）的高宽等信息

var query = wx.createSelectorQuery().select('.alerts-content').boundingClientRect()
query.exec(function (res) {
   console.log(res)
})

限制 text 组件文本行数

CSS样式中进行限制：
overflow: hidden;
display: -webkit-box;
-webkit-box-orient: vertical;
//当设置为 0 时，表示不限制行数
-webkit-line-clamp: 2;

通过百分比设置属性

width: calc(100% - 60rpx);
意思：设置宽为界面宽度的 100% ，同时两边总缩减 60rpx

设置渐变色背景

//线性渐变 linear-gradient(方向, 起始颜色, 结束颜色)
background: linear-gradient(to bottom right, #33bafd, #7835fe);

带值跳转界面

1. 在需要跳转的地方设置 data-xxx="xxxx"
2. 在点击事件中函数中接收传递的值
例如：
 <view class='video_item_detail' bindtap="navigateDetail" data-aid="{{item.id}}">
// 跳转至详情页
navigateDetail: function(e) {
    wx.navigateTo({
      url: '../videoDestail/videoDestail?id=' + e.currentTarget.dataset.aid
    })
}

关于 scroll-view 组件

//隐藏 scroll-view 的滑动条
::-webkit-scrollbar {
    width: 0;
   height: 0;
   color: transparent;
}

//注意事项：
1. scroll-view 需要指定滑动方向，如 scroll-y="true"，否则无法滑动；
2. scroll-view 需要指定高度，否则无法触发‘滑动到顶部’与‘滑动到底部’的函数；
3. 如果使用 scroll-view 将不会触发 js 中 Page 的 onPullDownRefresh() 与 onReachBottom() 函数；
4. 请勿在 scroll-view 中使用 textarea、map、canvas、video 组件；

隐藏 button 边框

//通过下面的方式可以实现隐藏边框
.btn::after {
  border: none
}
注意：不可设置 button 的 plain 为 ture！因为 plain 虽然实现了背景透明，但是会默认设置一个1rpx的实线边框，而且层级较高，导致上面方式会失效。推荐直接通过 background: transparent 设置。

关于 view 模板的使用

1. 新建 view 模板的 wxml 文件
<template name="xxxx">
 ....
</template>
2. 模板中的 css 样式全部集中在同一个 wxss 中
3. 在主 wxml 文件中使用：
//导入模板 wxml 文件
<import src="xxxx.wxml" />
//调用模板 is="模板 view 中的 name" data="需要传递给模板 view 的数据"
<template is="xxx" data="{{...item}}"/>

获取当前窗口的宽高

wx.getSystemInfo({
  success: function(res) {
    that.setData({
      winWidth: res.windowWidth,
      winHeight: res.windowHeight
    });
  }
});
//更多属性，请参照 https://developers.weixin.qq.com/miniprogram/dev/api/wx.getSystemInfo.html?search-key=getSystemInfo

关于 md5 加密

// md5.js
var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance   */
var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode      */

/*
 * These are the functions you'll usually want to call
 * They take string arguments and return either hex or base-64 encoded strings
 */
function hex_md5(s) {
  return binl2hex(core_md5(str2binl(s), s.length * chrsz));
}

function b64_md5(s) {
  return binl2b64(core_md5(str2binl(s), s.length * chrsz));
}

function str_md5(s) {
  return binl2str(core_md5(str2binl(s), s.length * chrsz));
}

function hex_hmac_md5(key, data) {
  return binl2hex(core_hmac_md5(key, data));
}

function b64_hmac_md5(key, data) {
  return binl2b64(core_hmac_md5(key, data));
}

function str_hmac_md5(key, data) {
  return binl2str(core_hmac_md5(key, data));
}

/*
 * Perform a simple self-test to see if the VM is working
 */
function md5_vm_test() {
  return hex_md5("abc") == "900150983cd24fb0d6963f7d28e17f72";
}

/*
 * Calculate the MD5 of an array of little-endian words, and a bit length
 */
function core_md5(x, len) {
  /* append padding */
  x[len >> 5] |= 0x80 << ((len) % 32);
  x[(((len + 64) >>> 9) << 4) + 14] = len;

  var a = 1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d = 271733878;

  for (var i = 0; i < x.length; i += 16) {
    var olda = a;
    var oldb = b;
    var oldc = c;
    var oldd = d;

    a = md5_ff(a, b, c, d, x[i + 0], 7, -680876936);
    d = md5_ff(d, a, b, c, x[i + 1], 12, -389564586);
    c = md5_ff(c, d, a, b, x[i + 2], 17, 606105819);
    b = md5_ff(b, c, d, a, x[i + 3], 22, -1044525330);
    a = md5_ff(a, b, c, d, x[i + 4], 7, -176418897);
    d = md5_ff(d, a, b, c, x[i + 5], 12, 1200080426);
    c = md5_ff(c, d, a, b, x[i + 6], 17, -1473231341);
    b = md5_ff(b, c, d, a, x[i + 7], 22, -45705983);
    a = md5_ff(a, b, c, d, x[i + 8], 7, 1770035416);
    d = md5_ff(d, a, b, c, x[i + 9], 12, -1958414417);
    c = md5_ff(c, d, a, b, x[i + 10], 17, -42063);
    b = md5_ff(b, c, d, a, x[i + 11], 22, -1990404162);
    a = md5_ff(a, b, c, d, x[i + 12], 7, 1804603682);
    d = md5_ff(d, a, b, c, x[i + 13], 12, -40341101);
    c = md5_ff(c, d, a, b, x[i + 14], 17, -1502002290);
    b = md5_ff(b, c, d, a, x[i + 15], 22, 1236535329);

    a = md5_gg(a, b, c, d, x[i + 1], 5, -165796510);
    d = md5_gg(d, a, b, c, x[i + 6], 9, -1069501632);
    c = md5_gg(c, d, a, b, x[i + 11], 14, 643717713);
    b = md5_gg(b, c, d, a, x[i + 0], 20, -373897302);
    a = md5_gg(a, b, c, d, x[i + 5], 5, -701558691);
    d = md5_gg(d, a, b, c, x[i + 10], 9, 38016083);
    c = md5_gg(c, d, a, b, x[i + 15], 14, -660478335);
    b = md5_gg(b, c, d, a, x[i + 4], 20, -405537848);
    a = md5_gg(a, b, c, d, x[i + 9], 5, 568446438);
    d = md5_gg(d, a, b, c, x[i + 14], 9, -1019803690);
    c = md5_gg(c, d, a, b, x[i + 3], 14, -187363961);
    b = md5_gg(b, c, d, a, x[i + 8], 20, 1163531501);
    a = md5_gg(a, b, c, d, x[i + 13], 5, -1444681467);
    d = md5_gg(d, a, b, c, x[i + 2], 9, -51403784);
    c = md5_gg(c, d, a, b, x[i + 7], 14, 1735328473);
    b = md5_gg(b, c, d, a, x[i + 12], 20, -1926607734);

    a = md5_hh(a, b, c, d, x[i + 5], 4, -378558);
    d = md5_hh(d, a, b, c, x[i + 8], 11, -2022574463);
    c = md5_hh(c, d, a, b, x[i + 11], 16, 1839030562);
    b = md5_hh(b, c, d, a, x[i + 14], 23, -35309556);
    a = md5_hh(a, b, c, d, x[i + 1], 4, -1530992060);
    d = md5_hh(d, a, b, c, x[i + 4], 11, 1272893353);
    c = md5_hh(c, d, a, b, x[i + 7], 16, -155497632);
    b = md5_hh(b, c, d, a, x[i + 10], 23, -1094730640);
    a = md5_hh(a, b, c, d, x[i + 13], 4, 681279174);
    d = md5_hh(d, a, b, c, x[i + 0], 11, -358537222);
    c = md5_hh(c, d, a, b, x[i + 3], 16, -722521979);
    b = md5_hh(b, c, d, a, x[i + 6], 23, 76029189);
    a = md5_hh(a, b, c, d, x[i + 9], 4, -640364487);
    d = md5_hh(d, a, b, c, x[i + 12], 11, -421815835);
    c = md5_hh(c, d, a, b, x[i + 15], 16, 530742520);
    b = md5_hh(b, c, d, a, x[i + 2], 23, -995338651);

    a = md5_ii(a, b, c, d, x[i + 0], 6, -198630844);
    d = md5_ii(d, a, b, c, x[i + 7], 10, 1126891415);
    c = md5_ii(c, d, a, b, x[i + 14], 15, -1416354905);
    b = md5_ii(b, c, d, a, x[i + 5], 21, -57434055);
    a = md5_ii(a, b, c, d, x[i + 12], 6, 1700485571);
    d = md5_ii(d, a, b, c, x[i + 3], 10, -1894986606);
    c = md5_ii(c, d, a, b, x[i + 10], 15, -1051523);
    b = md5_ii(b, c, d, a, x[i + 1], 21, -2054922799);
    a = md5_ii(a, b, c, d, x[i + 8], 6, 1873313359);
    d = md5_ii(d, a, b, c, x[i + 15], 10, -30611744);
    c = md5_ii(c, d, a, b, x[i + 6], 15, -1560198380);
    b = md5_ii(b, c, d, a, x[i + 13], 21, 1309151649);
    a = md5_ii(a, b, c, d, x[i + 4], 6, -145523070);
    d = md5_ii(d, a, b, c, x[i + 11], 10, -1120210379);
    c = md5_ii(c, d, a, b, x[i + 2], 15, 718787259);
    b = md5_ii(b, c, d, a, x[i + 9], 21, -343485551);

    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(c, oldc);
    d = safe_add(d, oldd);
  }
  return Array(a, b, c, d);

}

/*
 * These functions implement the four basic operations the algorithm uses.
 */
function md5_cmn(q, a, b, x, s, t) {
  return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
}

function md5_ff(a, b, c, d, x, s, t) {
  return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);
}

function md5_gg(a, b, c, d, x, s, t) {
  return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);
}

function md5_hh(a, b, c, d, x, s, t) {
  return md5_cmn(b ^ c ^ d, a, b, x, s, t);
}

function md5_ii(a, b, c, d, x, s, t) {
  return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);
}

/*
 * Calculate the HMAC-MD5, of a key and some data
 */
function core_hmac_md5(key, data) {
  var bkey = str2binl(key);
  if (bkey.length > 16) bkey = core_md5(bkey, key.length * chrsz);

  var ipad = Array(16),
    opad = Array(16);
  for (var i = 0; i < 16; i++) {
    ipad[i] = bkey[i] ^ 0x36363636;
    opad[i] = bkey[i] ^ 0x5C5C5C5C;
  }

  var hash = core_md5(ipad.concat(str2binl(data)), 512 + data.length * chrsz);
  return core_md5(opad.concat(hash), 512 + 128);
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safe_add(x, y) {
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}

/*
 * Bitwise rotate a 32-bit number to the left.
 */
function bit_rol(num, cnt) {
  return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * Convert a string to an array of little-endian words
 * If chrsz is ASCII, characters >255 have their hi-byte silently ignored.
 */
function str2binl(str) {
  var bin = Array();
  var mask = (1 << chrsz) - 1;
  for (var i = 0; i < str.length * chrsz; i += chrsz)
    bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (i % 32);
  return bin;
}

/*
 * Convert an array of little-endian words to a string
 */
function binl2str(bin) {
  var str = "";
  var mask = (1 << chrsz) - 1;
  for (var i = 0; i < bin.length * 32; i += chrsz)
    str += String.fromCharCode((bin[i >> 5] >>> (i % 32)) & mask);
  return str;
}

/*
 * Convert an array of little-endian words to a hex string.
 */
function binl2hex(binarray) {
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  for (var i = 0; i < binarray.length * 4; i++) {
    str += hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8 + 4)) & 0xF) +
      hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8)) & 0xF);
  }
  return str;
}

/*
 * Convert an array of little-endian words to a base-64 string
 */
function binl2b64(binarray) {
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  for (var i = 0; i < binarray.length * 4; i += 3) {
    var triplet = (((binarray[i >> 2] >> 8 * (i % 4)) & 0xFF) << 16) |
      (((binarray[i + 1 >> 2] >> 8 * ((i + 1) % 4)) & 0xFF) << 8) |
      ((binarray[i + 2 >> 2] >> 8 * ((i + 2) % 4)) & 0xFF);
    for (var j = 0; j < 4; j++) {
      if (i * 8 + j * 6 > binarray.length * 32) str += b64pad;
      else str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3F);
    }
  }
  return str;
}

module.exports = {
  b64Md5: b64_md5,
  hexMd5: hex_md5,
  strMD5: str_md5
}

1. 将上面文件拷入到对应文件夹内；（这里我放到 utils 中）
2. 导入文件 const md5 = require("../../utils/md5.js")
注意：文件中仅暴露几个方法；我在项目中仅仅用到了 md5.hexMd5

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