与数字钱包进行交互
当智能合约写好后，下一个步骤就是如何设计用户界面来与智能合约进行交互。在用户界面要调用链上的智能合约，必须通过数字钱包软件，下面的示例是演示的通过Anchor这个钱包来发送交易。实现的功能是调用eosio.token这个账号里的智能合约的transferAction。
下载Anchor钱包
桌面版本通过下面的链接下载选择最新版本下载：
https://github.com/greymass/anchor/tags
手机版本通过应用商店搜索Anchor Wallet进行下载
下载后导入EOS的账号的私钥即可使用，桌面版本也支持ledger硬件钱包
网页代码
下面这个html代码只依赖于anchor.min.js，可以在本地打开直接运行，完整的代码可以从下面的链接中找到，也可以直接尝试下面这个例子，需要事先安装好anchor钱包并且已经导入了账号私钥：
https://github.com/learnforpractice/ascdk-book/tree/master/examples/frontend
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>简单的HTML界面</title>
<style>
body {
margin: 0;
min-height: 100vh;
display: flex;
justify-content: center;
align-items: center;
background-color: #f0f0f0;
}
form {
background-color: #f0f0f0;
padding: 20px;
border-radius: 10px;
box-shadow: 0 2px 5px rgba(0, 0, 0, 0.5);
}
form button {
color: #ffffff; /* You can change this color to your desired foreground color */
background-color: #007bff;
padding: 5px 10px;
border: none;
border-radius: 5px;
cursor: pointer;
}
form button:hover {
background-color: #0056b3;
}
form label {
display: inline-block;
width: 100px; /* Adjust this value to set the desired width for the labels */
text-align: left;
margin-right: 10px;
}
</style>
<script src="./anchor.min.js"></script>
<script>
const eos = {
chainId: 'aca376f206b8fc25a6ed44dbdc66547c36c6c33e3a119ffbeaef943642f0e906',
rpcEndpoints: [{
protocol: 'https',
host: 'eos.greymass.com',
port: '443',
}]
}
var wallet = new anchor.Anchor([eos], {
// Required: The app name, required by anchor-link. Short string identifying the app
appName: 'my-example-dapp',
// Optional: a @greymass/eosio APIClient from eosjs for both your use and to use internally in UAL
// client = new APIClient({ provider }),
// Optional: a JsonRpc instance from eosjs for your use
// rpc: new JsonRpc(),
// Optional: The callback service URL to use, defaults to https://cb.anchor.link
service: 'https://cb.anchor.link',
// Optional: A flag to disable the Greymass Fuel integration, defaults to false (enabled)
// disableGreymassFuel: false,
// Optional: An account name on a Fuel enabled network to specify as the referrer for transactions
// fuelReferrer: 'teamgreymass',
// Optional: A flag to enable the Anchor Link UI request status, defaults to true (enabled)
// requestStatus: true,
// Optional: Whether or not to verify the signatures during user login, defaults to false (disabled)
// verifyProofs: false,
});
(async () => {
await wallet.init();
})();
window.wallet = wallet;
</script>
</head>
<body>
<form>
<button type="button" id="login">Login</button>
<button type="button" id="logout">Logout</button><br><br>
<label for="account">To Account:</label>
<input type="text" id="account" name="account"><br><br>
<label for="amount">Quantity:</label>
<input type="number" id="amount" name="amount" value="0.0001"><label>EOS</label><br><br>
<label for="memo">Memo:</label>
<input type="text" id="memo" name="memo" value="hello world"><br><br>
<button type="button" id="transfer">Transfer</button>
</form>
<script>
document.getElementById("transfer").addEventListener("click", async function() {
if (wallet.users.length == 0) {
alert("please login first!");
return;
}
let account = document.getElementById("account").value;
let amount = document.getElementById("amount").value;
let memo = document.getElementById("memo").value;
console.log("Account: " + account);
console.log("Amount: " + amount);
console.log("Memo: " + memo);
amount = parseFloat(amount).toFixed(4);
let user = wallet.users[0];
let args = {
action: {
account: 'eosio.token',
name: 'transfer',
authorization: [user.session.auth],
data: {
from: user.session.auth.actor,
to: account,
quantity: `${amount} EOS`,
memo: memo,
},
},
}
var ret = await user.session.transact(args);
console.log(ret);
alert(JSON.stringify(ret.processed));
});
document.getElementById("login").addEventListener("click", async function() {
if (wallet.users.length == 0) {
var ret = await wallet.login();
console.log("++++++:", ret);
}
});
document.getElementById("logout").addEventListener("click", async function() {
if (wallet.users.length != 0) {
await wallet.logout();
}
});
</script>
</body>
</html>
简单解释下：
当网页初始化后，会调用new anchor.Anchor来创建一个钱包实例。然后调用wallet.init进行初始化，注意init是一个异步函数
var wallet = new anchor.Anchor
wallet.init()
点Login先连接钱包客户端，会弹出一个对话框，点Launch Anchor打开桌面钱包或者手机上打开Anchor软件进行扫码进行授权。
await wallet.login()
点Logout取消授权
await wallet.logout()
注意login和logout两个函数都是异步的
输入合法的转账账号和转账的数额，然后点Transfer即会在手机或者桌面软件上弹出授权对话框进行授权。请确保界面上描述的Action准确无误后才能确认授权。下面是相关的代码，调用了eosio.token的transfer这个Action。
let user = wallet.users[0];
let args = {
action: {
account: 'eosio.token',
name: 'transfer',
authorization: [user.session.auth],
data: {
from: user.session.auth.actor,
to: account,
quantity: `${amount} EOS`,
memo: memo,
},
},
}
var ret = await user.session.transact(args);
总结：
上面的例子中anchor.min.js是用的用到了下面的库经过webpack后生成的代码
https://github.com/greymass/ual-anchor
上面的例子只是演示了一个最简单的例子，在实际的例子中，可能要用到vuejs,react,svelte等应用框架，这些框架都可以直接使用ual-anchor这个库。实现也可以参考一下的示例：
https://github.com/greymass/ual-anchor-demo