Android使用JSON進行數據解析

Android使用JSON進行數據解析

一、Json數據格式的定義

Json的全稱：JavaScript Object Notation

Json建構於兩種結構：對象（“名稱/值”對的集合）和數組（值得有序列表）

1.Json對象是一個無序“名稱/值對”的集合。如： {“name”: “jack”, “age”:100}

2.數組是值得有序結合。如：{“students”:[{“name”: “jack”, “age”:100} ,{“name”: “tom”, “age”:10}]}

下面我們通過訪問一個JSON數據的網址連接來進行數據解析並在Android客戶端進行顯示（id、pinyin、name）

完成效果：

佈局文件：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" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="ID" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="NAME" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="PINYIN" />
    </LinearLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="?android:attr/listDivider" />

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

cell.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/id"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <TextView
        android:id="@+id/name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <TextView
        android:id="@+id/pinyin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

</LinearLayout>

HttpUtils類

public class HttpUtils {

	public static String getJsonString(String path) {
		try {
			URL url = new URL(path);
			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
			conn.setConnectTimeout(3000);
			conn.setRequestMethod("GET");
			conn.setDoInput(true);
			if (conn.getResponseCode() == 200) {
				return changeInputStream(conn.getInputStream());
			}
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "";
	}

	private static String changeInputStream(InputStream inputStream) {
		// TODO Auto-generated method stub
		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
		String jsonString = "";
		int len = 0;
		byte[] data = new byte[1024];
		try {
			while ((len = inputStream.read(data)) != -1) {
				outputStream.write(data, 0, len);
			}
			jsonString = new String(outputStream.toByteArray());
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return jsonString;
	}
}

JsonTools類

public class JsonTools {

	public static List<City> getListPersons(String key, String jsonString) {
		List<City> list = new ArrayList<City>();
		try {
			JSONObject object = new JSONObject(jsonString);
			JSONArray array = object.getJSONArray(key);
			for (int i = 0; i < array.length(); i++) {
				JSONObject jsonObject = array.getJSONObject(i);
				City city = new City();
				city.setId(jsonObject.getInt("id"));
				city.setName(jsonObject.getString("name"));
				city.setPinyin(jsonObject.getString("pinyin"));
				list.add(city);
			}
		} catch (JSONException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return list;
	}
}

實體類City

public class City {
	private String name;
	private int id;
	private String pinyin;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getPinyin() {
		return pinyin;
	}

	public void setPinyin(String pinyin) {
		this.pinyin = pinyin;
	}

	@Override
	public String toString() {
		return "City [name=" + name + ", id=" + id + ", pinyin=" + pinyin + "]";
	}

	public City(String name, int id, String pinyin) {
		super();
		this.name = name;
		this.id = id;
		this.pinyin = pinyin;
	}

	public City() {
		super();
	}

}

MainActivity

public class MainActivity extends Activity {

	private ListView listView;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		listView = (ListView) findViewById(R.id.listview);

		List<Map<String, Object>> data = new ArrayList<Map<String, Object>>();

		String path = "這裏填寫JSON數據的網址連接";
		List<City> cities = JsonTools.getListPersons("cities",
				HttpUtils.getJsonString(path));

		for (City city : cities) {
			Map<String, Object> map = new HashMap<String, Object>();
			map.put("ID", city.getId());
			map.put("NAME", city.getName());
			map.put("PINYIN", city.getPinyin());

			data.add(map);
		}

		SimpleAdapter adapter = new SimpleAdapter(MainActivity.this, data,
				R.layout.cell, new String[] { "ID", "NAME", "PINYIN" },
				new int[] { R.id.id, R.id.name, R.id.pinyin });
		listView.setAdapter(adapter);
	}
}