uniapp 获取控件高度 控件剩余100%

uni.getSystemInfo({
				success: res => {
					uni.createSelectorQuery().select(".uni-search-bar")
						.boundingClientRect(searchBarBoundRect => {
							uni.createSelectorQuery().select(".uni-card")
								.boundingClientRect(cardBoundRect => {
									this.mapHeight = res.windowHeight - searchBarBoundRect.height - cardBoundRect.height-30;
								}).exec();
						}).exec();
				}
			});