uniapp怎么改变checkbox选中状态

<checkbox-group @change="checkboxChange" name="limitarea" >
<label>
<checkbox value="1" :checked="limitArea"/>
<text>限定地区</text>
</label>
</checkbox-group>
<script>
export default {
data() {
return {
limitArea:0
}
},
methods: {
checkboxChange: function(e){
var self = this;
if( e.detail.value.length > 0 ){
uni.showModal({
title: &#39;限定地区&#39;,
content: &#39;限定地区，可能需要等待较长时间&#39;,
confirmText: "确定",
cancelText: "取消",
success: function (res) {
if (res.confirm) {
self.limitArea = 1;
}else{
self.limitArea = 0;
}
}
});
}else{
this.limitArea = 0;
}
}
},
components: {}
}
</script>

checkboxChange: function(e){
var self = this;
if( e.detail.value.length > 0 ){//点击勾选
self.limitArea = 1;  // *****加上这句代码*******
uni.showModal({
title: '限定地区',
content: '限定地区，可能需要等待较长时间',
confirmText: "确定",
cancelText: "取消",
success: function (res) {
if (res.confirm) {
self.limitArea = 1;
}else{
self.limitArea = 0;
}
}
});
}else{
this.limitArea = 0;
}
}