前言

前言无需多言，想必大家对聊天软件的功能已经很熟悉，这里不做过多赘述，笔者通过uniapp实现聊天中的接发消息自动滚动、消息定位和回到底部。

代码实现

<template><view class="chat-container"><!-- 消息列表 --><scroll-viewclass="message-list"scroll-ystyle="height: 300px;"upper-threshold="200":scroll-into-view="'message-item-' + scrollMsgIdx":scroll-with-animation="true"@scroll="handleScroll"><view class="message-item-box" v-for="(item, idx) in chatMessageList" :key="item.id" :id="'message-item-' + idx"><view :class="['message-item', item.self === true ? 'right' : 'left']"><view class="message-content">{{ item.content }}</view></view></view></scroll-view><view class="back-to-bottom-btn" @click="scrollToBottom" v-if="showBackBottomBtn">回到底部</view><!-- 输入区域 --><view class="content-area"><view class="input-box"><textarea v-model="inputText" placeholder="输入内容" maxlength="500" auto-height/></view><button class="send-btn" @click="sendMsg" size="mini">发送</button><button class="jump-btn" @click="jumpMsg" size="mini">定位</button></view></view>
</template><script setup>
import {onLoad} from '@dcloudio/uni-app';
import {nextTick, ref} from "vue";const scrollMsgIdx = ref(0); // 滚动控制
const showBackBottomBtn = ref(false); // 回到底部按钮显示
const inputText = ref(''); // 输入文本
const chatMessageList = ref([{id: 0, content: '请求添加你为好友？', self: false},{id: 1, content: '你好', self: false},{id: 2, content: '你是谁啊？', self: true},{id: 3, content: '我是你爸爸啊', self: false},{id: 4, content: '？？？', self: true},{id: 5, content: '我是你爷爷', self: true},{id: 6, content: '你真的是个老六', self: false},{id: 7, content: '谁让你张口就来', self: true},{id: 8, content: '再问一遍你是谁？', self: true},{id: 9, content: '我是张三，你叔叔介绍的相亲对象', self: false},{id: 10, content: '哦哦', self: true},{id: 11, content: '那你今年多大了？', self: true},{id: 12, content: '27', self: false},{id: 13, content: '那你哪个学校毕业的啊？', self: true},{id: 14, content: '在哪里工作？', self: true},{id: 15, content: '毕业于家里蹲大学', self: false},{id: 16, content: '现在没工作', self: false},{id: 17, content: '啊？那你用钱了怎么办啊', self: true},{id: 18, content: '你管我啊', self: false},{id: 19, content: '那你自己看着办吧！', self: true},{id: 20, content: '好的', self: false},{id: 21, content: '不用你操心哦', self: false},{id: 22, content: '替你家长操心！', self: true},{id: 23, content: '那也不需要', self: false},{id: 24, content: '你大学学的啥啊？工作都找不到', self: true},{id: 25, content: '大学光挂科去了', self: false},{id: 26, content: '那怪不得', self: true},{id: 27, content: '好自为之吧', self: true},
]); // 消息列表onLoad(() => {// 回到底部scrollToBottom();
});// 发送消息
function sendMsg() {if (!inputText.value.trim()) {console.log('不能发送空白信息');return;}chatMessageList.value.push({id: Date.now(), content: inputText.value, self: true});inputText.value = '';chatMessageList.value.push({id: Date.now(), content: '自动回复', self: false});// 回到底部scrollToBottom();
}// 跳转指定消息
function jumpMsg() {if (!inputText.value.trim()) {console.log('不能发送空白信息');return;}scrollToMsgIdx(Number(inputText.value));inputText.value = '';
}// 滚动事件处理
function handleScroll(e) {const { scrollTop, scrollHeight } = e.detail;const screenHeight = uni.getSystemInfoSync().screenHeight;showBackBottomBtn.value = scrollHeight - screenHeight - scrollTop > 50;
}// 滚动到底部
function scrollToBottom() {let length = chatMessageList.value.length;if (length > 0) {scrollToMsgIdx(length - 1);}
}// 滚动到指定消息
function scrollToMsgIdx(idx) {nextTick(() => {scrollMsgIdx.value = (idx < 0 || idx > chatMessageList.value.length - 1) ? 0 : idx;showBackBottomBtn.value = chatMessageList.value.length - 1 - scrollMsgIdx.value > 0;});
}
</script><style lang="scss" scoped>
.chat-container {display: flex;flex-direction: column;height: 100vh;background-color: #f5f5f5;.message-list {flex: 1;margin-top: 10px;overflow: auto;background-color: #f5f5f5;.message-item-box {margin: 10px;}.message-item {display: flex;&.left {justify-content: flex-start;.message-content {margin-left: 10px;background-color: #fff;}}&.right {justify-content: flex-end;.message-content {margin-right: 10px;background-color: #95ec69;}}.message-content {max-width: 70%;border-radius: 2px;box-sizing: border-box;word-break: break-word;height: auto;padding: 10px;}}}.content-area {display: flex;align-items: center;padding: 8px 10px;background-color: #fff;border-top: 1px solid #eee;.input-box {flex: 4;textarea {box-sizing: border-box;width: 100%;background-color: #f5f5f5;border-radius: 4px;padding: 8px;font-size: 14px;}}.send-btn {flex: 1;text-align: center;align-items: center;background-color: #07c160;color: #ffffff;font-size: 12px;padding: 2px !important;}.jump-btn {flex: 1;text-align: center;align-items: center;background-color: #97aca1;color: #ffffff;font-size: 12px;padding: 2px !important;}}.back-to-bottom-btn {position: fixed;bottom: 55px;right: 10px;background-color: #575859;color: #ffffff;padding: 5px;border-radius: 4px;font-size: 12px;z-index: 999;}
}
</style>