【实战】android获取天气情况（Json来返回数据）

在输入框输入查询的城市，即可输出天气情况

一、android工程结构：

、

MainActivity.java:

package com.lcz.research;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.net.URLEncoder;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import com.lcz.research.utils.StreamTool;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.app.Activity;import android.app.ProgressDialog;import android.text.TextUtils;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity implements View.OnClickListener {private Button btn;private EditText ed_city;private TextView city_result1;private TextView city_result2;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        btn=(Button) findViewById(R.id.btn);        btn.setOnClickListener(this);                ed_city=(EditText) findViewById(R.id.ed_city);        city_result1=(TextView) findViewById(R.id.city_result1);        city_result2=(TextView) findViewById(R.id.city_result2);    }        private final static String PATH="http://wthrcdn.etouch.cn/weather_mini?city=";protected static final int SUCCESS = 0;protected static final int INVALID_CITY = 1;protected static final int ERROR = 2;    private String city;    String ul;            private Handler mhandler=new Handler(){    public void handleMessage(android.os.Message msg) {    dialog.dismiss();    switch (msg.what) {case SUCCESS:JSONArray data=(JSONArray) msg.obj;try {String day01= data.getString(0);String day02= data.getString(1);city_result1.setText(day01);city_result2.setText(day02);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}break;case INVALID_CITY:Toast.makeText(MainActivity.this, "城市无效", 0).show();break;case ERROR:Toast.makeText(MainActivity.this, "网络无效", 0).show();break;default:break;}    };    };    ProgressDialog dialog=null;    public void onClick(View v) {// TODO Auto-generated method stubcity=ed_city.getText().toString().trim();if(TextUtils.isEmpty(city)){Toast.makeText(this, "路径错误", 0).show();return ;}dialog=new ProgressDialog(this);dialog.setMessage("正在玩命加载中");dialog.show();//发起请求给那个网站new Thread(){public void run() {try {    ul=PATH+URLEncoder.encode(city,"UTF-8");URL url=new URL(ul);//设置必要的参数信息HttpURLConnection conn=(HttpURLConnection) url.openConnection();conn.setConnectTimeout(5000);conn.setRequestMethod("GET");//判断响应码int code = conn.getResponseCode();if(code==200){//连接网络成功InputStream in = conn.getInputStream();String data = StreamTool.decodeStream(in);//解析json格式的数据JSONObject jsonObj=new JSONObject(data);//获得desc的值String result = jsonObj.getString("desc");if("OK".equals(result)){//城市有效，返回了需要的数据JSONObject dataObj = jsonObj.getJSONObject("data");JSONArray jsonArray = dataObj.getJSONArray("forecast");//通知更新uiMessage msg = Message.obtain();msg.obj=jsonArray;msg.what=SUCCESS;mhandler.sendMessage(msg);}else{//城市无效Message msg=Message.obtain();msg.what=INVALID_CITY;mhandler.sendMessage(msg);}}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();Message msg = Message.obtain();msg.what=ERROR;mhandler.sendMessage(msg);}};}.start();}    }

StreamTool.java:

package com.lcz.research.utils;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;public class StreamTool {public static String decodeStream(InputStream in) throws IOException {// 底层流ByteArrayOutputStream baos = new ByteArrayOutputStream();int len =0;byte[] buf = new byte[1024];while((len=in.read(buf))>0){baos.write(buf, 0, len);}String data = baos.toString();return data;}}

2.activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"  android:orientation="vertical"    tools:context=".MainActivity" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="请输入你要查询的城市" /> <EditText       android:id="@+id/ed_city"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        /> <Button    android:id="@+id/btn"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="查询" />  <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/city_result1" />  <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/city_result2" /></LinearLayout>

3.AndroidMainfest.xml

    <uses-permission android:name="android.permission.INTERNET"/>