学习安卓有一段时间了,应该提高自己的实战能力,做一些简单的Demo。下面我们介绍一下如何利用网络API实现天气预报功能,主要涉及到如何利用API获得网络数据,网络数据返回一般是JSON格式,这里又涉及到JSON的解析问题,这些都是比较基础的问题,应该予以掌握。
首先在http://apistore.baidu.com/?qq-pf-to=pcqq.c2c找到你想要的API,这里我们选择http://apistore.baidu.com/astore/serviceinfo/1798.html,网页里有关于API的介绍:
接口地址:http://apistore.baidu.com/microservice/weather
请求方法:GET
请求参数:
参数名 | 类型 | 必填 | 参数位置 | 描述 | 默认值 |
citypinyin | string | 是 | urlParam | 城市拼音 | beijing |
请求示例:
http://apistore.baidu.com/microservice/weather?citypinyin=beijing
JSON返回示例:
{
errNum: 0,
errMsg: "success",
retData: {
city: "北京", //城市
pinyin: "beijing", //城市拼音
citycode: "101010100", //城市编码
date: "15-02-11", //日期
time: "11:00", //发布时间
postCode: "100000", //邮编
longitude: 116.391, //经度
latitude: 39.904, //维度
altitude: "33", //海拔
weather: "晴", //天气情况
temp: "10", //气温
l_tmp: "-4", //最低气温
h_tmp: "10", //最高气温
WD: "无持续风向", //风向
WS: "微风(<10m/h)", //风力
sunrise: "07:12", //日出时间
sunset: "17:44" //日落时间
}
}
下面搞一下布局文件:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:text="天气预报"
android:textSize="26dp" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:orientation="horizontal" >
<EditText
android:id="@+id/myedit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1111" />
<Button
android:id="@+id/searchweather"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="查询天气 " />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:orientation="horizontal" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="城市:" />
<TextView
android:id="@+id/city"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:orientation="horizontal" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="天气:" />
<TextView
android:id="@+id/weather"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:orientation="horizontal" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="实时气温:" />
<TextView
android:id="@+id/temp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:orientation="horizontal" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="最低气温:" />
<TextView
android:id="@+id/h_temp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="30dp"
android:orientation="horizontal" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="最高气温:" />
<TextView
android:id="@+id/l_temp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
</LinearLayout>
下面连接工具类:
package org.lxh.demo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class HttpDownloader {
private URL url = null;
/**
* 根据URL下载文件,前提是这个文件当中的内容是文本,函数的返回值就是文本当中的内容 1.创建一个URL对象
* 2.通过URL对象,创建一个HttpURLConnection对象 3.得到InputStream 4.从InputStream当中读取数据
*
* @param urlStr
* @return
*/
public String download(String urlStr) {
StringBuffer sb = new StringBuffer();
String line = null;
BufferedReader buffer = null;
try {
url = new URL(urlStr);
HttpURLConnection urlConn = (HttpURLConnection) url
.openConnection();
urlConn.setRequestMethod("GET");
urlConn.setConnectTimeout(8000);
urlConn.setReadTimeout(8000);
buffer = new BufferedReader(new InputStreamReader(
urlConn.getInputStream()));
while ((line = buffer.readLine()) != null) {
sb.append(line);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
buffer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
获取返回字符串之后要对此JSON数据进行解析:
package org.lxh.demo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.json.JSONObject;
public class Util {
public List<Map<String, Object>> getInformation(String jonString)
throws Exception {
JSONObject jsonObject = new JSONObject(jonString);
JSONObject retData = jsonObject.getJSONObject("retData");
List<Map<String, Object>> all = new ArrayList<Map<String, Object>>();
Map<String, Object> map = new HashMap<String, Object>();
map.put("cityName", retData.optString("city"));
map.put("weather", retData.optString("weather"));
map.put("temp", retData.optString("temp"));
map.put("l_temp", retData.optString("l_tmp"));
map.put("h_temp", retData.optString("h_tmp"));
all.add(map);
return all;
}
}
下面Activity程序:
package org.lxh.demo;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Main extends Activity {
private EditText citynameEditText;
private Button searchWeatherButton;
private TextView citynametTextView;
private TextView weahterTextView;
private TextView tempTextView;
private TextView h_tempTextView;
private TextView l_tempTextView;
String jonString;
ProgressDialog progressDialog;
private static final int SET = 1;
@SuppressLint("HandlerLeak")
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SET:
Util util = new Util();
try {
List<Map<String, Object>> all = util
.getInformation(msg.obj.toString());
Iterator<Map<String, Object>> iterator = all.iterator();
while (iterator.hasNext()) {
Map<String, Object> map = iterator.next();
Log.d("天气", map.get("weather").toString());
citynametTextView.setText(map.get("cityName")
.toString());
weahterTextView.setText(map.get("weather").toString());
tempTextView.setText(map.get("temp").toString());
h_tempTextView.setText(map.get("l_temp").toString());
l_tempTextView.setText(map.get("h_temp").toString());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
}
break;
}
}
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); // 生命周期方法
super.setContentView(R.layout.main); // 设置要使用的布局管理器
citynameEditText = (EditText) findViewById(R.id.myedit);
searchWeatherButton = (Button) findViewById(R.id.searchweather);
citynametTextView = (TextView) findViewById(R.id.city);
weahterTextView = (TextView) findViewById(R.id.weather);
tempTextView = (TextView) findViewById(R.id.temp);
h_tempTextView = (TextView) findViewById(R.id.h_temp);
l_tempTextView = (TextView) findViewById(R.id.l_temp);
searchWeatherButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
new Thread(new NewThread()).start();
Log.d("按键", "Success");
}
});
}
private class NewThread implements Runnable {
public void run() {
String address = "http://apistore.baidu.com/microservice/weather?citypinyin="
+ citynameEditText.getText().toString();
HttpDownloader httpDownloader = new HttpDownloader();
String jonString = httpDownloader.download(address);
Message msg = Main.this.handler
.obtainMessage(Main.SET, jonString);
Main.this.handler.sendMessage(msg);
}
}
}
运行实例效果: