Interpretation of Amap API documentation: Java code to implement bus online running status query

Interpretation of the Amap API document: Java code to implement online bus running status query

Introduction: With the development of cities, the importance of public transportation has become increasingly prominent. People have a strong demand for the running status of buses, such as real-time arrival time, congestion level and other information. Amap provides a powerful API to meet this need. This article will interpret the Amap API document, use Java code to query the online running status of buses, and provide code examples.

1. API Overview
   Amap API provides rich bus query functions, including real-time bus location, single line bus location, designated line bus location, etc. Developers can choose the appropriate interface to call based on specific needs, and parse the required information from the returned JSON data.
2. Get the Developer Key
   Before using the Amap API, you need to apply for the Developer Key. Only by carrying a valid Key can you successfully access the API service. The application process is very simple. You only need to register in the developer center of the Amap open platform and create an application to obtain the Key.
3. Introducing the Amap API SDK
   To use Java to query the online running status of buses, you need to first introduce the Java version SDK of the Amap API. You can find the SDK download link on the Amap official website and include the SDK into the project's dependencies.
4. Query real-time bus location
   In the Java code, calling the real-time bus location query interface of the Amap API requires passing in the three parameters of longitude, latitude and line ID. The longitude and latitude are used to determine the location, and the line ID is used to specify the bus line to be queried.

The following is a Java code example that calls the real-time bus location query interface:

import com.amap.api.maps.model.LatLng;
import com.amap.api.services.busline.BusLineQuery;
import com.amap.api.services.busline.BusLineSearch;
import com.amap.api.services.busline.BusLineSearch.OnBusLineSearchListener;
import com.amap.api.services.busline.BusLineItem;
import com.amap.api.services.busline.BusLineResult;

public class BusLineSearchExample {
    private static final String KEY = "your_amap_api_key";

    public static void main(String[] args) {
        // 初始化查询对象
        BusLineQuery query = new BusLineQuery("bus_line_id", BusLineQuery.SearchType.BY_LINE_ID, "city_code");
        // 设置查询结果监听器
        BusLineSearch search = new BusLineSearch(context, query);
        search.setOnBusLineSearchListener(new OnBusLineSearchListener() {
            @Override
            public void onBusLineSearched(BusLineResult result, int rCode) {
                if (rCode == 1000) {
                    // 查询成功，处理结果
                    for (BusLineItem item : result.getBusLines()) {
                        // 获取公交车位置信息
                        LatLng position = item.getBusStations().get(item.getBusStations().size() - 1).getLatLonPoint();
                        // 处理位置信息
                        // ...
                    }
                } else {
                    // 查询失败，处理错误信息
                    // ...
                }
            }
        });
        // 发起查询
        search.searchBusLineAsyn();
    }
}

In the code example, first create a query object by passing in the bus line ID and city code. Then set the query result listener. When the query is successful, the bus line object list is obtained through the getBusLines() method, and the bus location information can be further obtained. Finally, initiate a query through the searchBusLineAsyn() method.

It should be noted that since calling the Amap API requires a valid Key, you need to replace the Key with the Key you applied for in the code example.

5. Other bus query interface
   In addition to the real-time bus location query interface, the Amap API also provides other bus query interfaces, such as querying the bus location of a single line and specifying the bus location. Location etc. Developers can choose the appropriate interface to call based on specific needs, and parse the returned JSON data according to the API document.

Conclusion: This article interprets the Amap API document, uses Java code to implement bus online running status query, and provides code examples. Readers can refer to the code examples and adjust them according to actual needs to develop a more powerful and practical bus query application. At the same time, developers can also explore other functions of the Amap API to create a smarter and more convenient urban transportation system.

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