列表数组中插入数据后，刷新UI的问题

dataArray: T[] = [];  
let oldArr: ObservedArray<T> = [];  
for(let a of this.dataArray) {  
  oldArr.push(a);  
}  
  
oldArr.splice(index, 0, ...newData);  
  
this.clear();  
this.dataArray.push(...newData);  
this.notifyDataReload();