初学_Android4高级编程-7 异步http框架得到有道翻译的XML与json资源并解析出需要的数据&使用DownloadManager

※使用URLConnection连接Internet资源
try {
URL url = new URL("www.baidu.com");
URLConnection connection = url.openConnection();
HttpURLConnection httpURLConnection = (HttpURLConnection) connection;
int responseCode = httpURLConnection.getResponseCode();
if(responseCode == 200){
InputStream inputStream = httpURLConnection.getInputStream();
}
} catch (IOException e) {
e.printStackTrace();
}

※使用AsyncHttpClient连接有道翻译，获取xml，json格式的资源并解析。

初始化组件
textView = (TextView) findViewById(R.id.id_textview);
textView2 = (TextView) findViewById(R.id.id_textview2);
editText = (EditText) findViewById(R.id.id_edit_text);
Button button = (Button) findViewById(R.id.id_button_json);
Button button1 = (Button) findViewById(R.id.id_button_xml);
button.setOnClickListener(this);
button1.setOnClickListener(this);

点击事件
@Override
public void onClick(View v) {
    switch (v.getId()){
        case R.id.id_button_xml:
            connect("xml");
            break;
        case R.id.id_button_json:
            connect("json");
            break;
    }
}

//连接有道翻译并获取资源
public void connect(final String doctype){
    final AsyncHttpClient httpClient = new AsyncHttpClient();
    RequestParams params = new RequestParams();
    params.put("keyfrom", "sdasfafas");
    params.put("key", "66594842");
    params.put("type", "data");
    params.put("doctype", doctype);
    params.put("version", "1.1");
    params.put("q", editText.getText());
    httpClient.get("http://fanyi.youdao.com/openapi.do", params, new AsyncHttpResponseHandler() {
        @Override
        public void onSuccess(int i, Header[] headers, byte[] bytes) {
            if(doctype.equals("xml")){
                try {
                    textView2.setText("xml格式\n" + parsingXml(new ByteArrayInputStream(bytes)));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            } else {
                textView.setText("json格式\n" + parsingJson(bytes));
            }
        }
        @Override
        public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {
            textView.setText("连接失败");
            textView2.setText("");
        }
    });
}

//解析Json
public String parsingJson(byte[] bytes) {
    StringBuilder ans = new StringBuilder();
    try {
        JSONObject jsonObject = new JSONObject(new String(bytes, "UTF-8"));
        JSONArray jsonArray = jsonObject.getJSONObject("basic").getJSONArray("explains");
        for (int j = 0; j < jsonArray.length(); j++) {
            if (j != 0) {
                ans.append("\n");
            }
            ans.append(jsonArray.getString(j));
        }
    } catch (JSONException | UnsupportedEncodingException e) {
        e.printStackTrace();
    }
    return ans.toString();
}

//解析Xml
public String parsingXml(InputStream inputStream) throws Exception {
    StringBuffer ans = new StringBuffer();
    XmlPullParser parser = Xml.newPullParser();
    parser.setInput(inputStream, "UTF-8");
    int eventType = parser.getEventType();
    parser.next();
    while (eventType != XmlPullParser.END_DOCUMENT) {
        if (eventType == XmlPullParser.START_TAG && parser.getName().equals("explains")) {
            parser.nextTag();
            while (eventType == XmlPullParser.START_TAG && parser.getName().equals("ex")) {
                parser.next();
                ans.append(parser.getText()).append("\n");
                parser.nextTag();
                eventType = parser.nextTag();
            }
        }
        eventType = parser.next();
    }
    return ans.toString();
}

※使用DownloadManager下载文件
下载文件并动态注册一个广播接收器监听下载完成
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
final TextView textView = (TextView) findViewById(R.id.text_view);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
DownloadManager downloadManager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse("http://www.baidu.com/link?url=tFfogxNoCPbAgWS5g2dsoOmx0IO-oNS8N4f2UFcLkuSopfdQvD81Nc2sBD8aMxjdsU8wos9J4DIaJV9DJY0ARSj_0qR_RUVan_aUkHNWKGvELk0MPT5Vst5fQ4HsipCd");
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setDescription("百度手机助手");
//下载完成后也会继续在标题栏显示Notification
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
long reference = downloadManager.enqueue(request);
}
});
thread.start();
}
});

    IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
    BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            long refrence = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID,-1);
            textView.setText("Complete , "+refrence);
        }
    };
    registerReceiver(receiver,filter);
}