使用 let that = this;

demo(){
	let that = this;
	dd.getLocation({
	  success(res) {
		that.location = res;
	  },
	  fail() {
		dd.alert({ title: '定位失败' });
	  },
	})
}

使用箭头函数;

demo(){
	dd.getLocation({
	  success:(res)=> {
		this.location = res;
	  },
	  fail() {
		dd.alert({ title: '定位失败' });
	  },
	})
}

在成功方法内调用成功后需要执行的方法

demo(){
	let that = this
	dd.getLocation({
	  success:(res)=> {
			that.demo1(res.data);
	  },
	  fail() {
		dd.alert({ title: '定位失败' });
	  },
	})
}，
demo1(val){
	console,log(val);
}