Question

我也想对列表进行升序和降序排序。我想做到这一点而不使用覆盖方法。我已经尝试过"dependencies": { "@mauron85/react-native-background-geolocation": "^0.6.3", "@react-native-community/async-storage": "^1.9.0", "@react-native-community/masked-view": "^0.1.10", "@react-navigation/drawer": "^5.8.2", "@react-navigation/material-bottom-tabs": "^5.1.6", "@react-navigation/native": "^5.5.1", "@react-navigation/stack": "^5.0.6", "react": "16.11.0", "react-native": "0.62.2", "react-native-action-button": "^2.8.5", "react-native-animatable": "^1.3.3", "react-native-background-timer": "^2.2.0", "react-native-camera": "git+https://git@github.com/react-native-community/react-native-camera.git", "react-native-geolocation-service": "^5.0.0", "react-native-gesture-handler": "^1.6.1", "react-native-linear-gradient": "^2.5.6", "react-native-maps": "^0.27.1", "react-native-paper": "^3.6.1", "react-native-reanimated": "^1.9.0", "react-native-safe-area-context": "^3.0.5", "react-native-screens": "^2.9.0", "react-native-vector-icons": "^6.6.0", "rn-fetch-blob": "^0.12.0" },。效果很好。但是我想找到另一种方法。有人可以帮我吗？

Collections.reverse()

Answer 1

collections.sort方法接受具有排序方法的comparator。该方法的javadoc提供了答案：

第一个参数小于，等于或大于第二个参数时，为负整数，零或正整数。

因此，通过更改返回的值，可以更改顺序。您可以编写自己的代码，也可以使用原始类型的实现（因为您是通过double值进行排序的）。升序：

 @Override
    public int compare(ModelPortfolioDTO o1, ModelPortfolioDTO o2) {
        return Double.compare(Double.parseDouble(o1.getSharpRatio()), Double.parseDouble(o2.getSharpRatio()));
    }

降序（注意元素的倒序）：

 @Override
public int compare(ModelPortfolioDTO o1, ModelPortfolioDTO o2) {
    return Double.compare(Double.parseDouble(o2.getSharpRatio()), Double.parseDouble(o1.getSharpRatio()));
}

降序排序

1 个答案: