Unit9：網路技術
阿新 • • 發佈：2020-09-21
1. 使用webView
res中：
<WebView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/web_view"
/>
java中：
WebView webView = findViewById(R.id.web_view); webView.getSettings().setJavaScriptEnabled(true); webView.setWebViewClient(new WebViewClient()); // 網頁跳轉在WebView中顯示 webView.loadUrl("http://www.baidu.com");
.xml中：
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
...
android:requestLegacyExternalStorage="true"
android:usesCleartextTraffic="true">
2. 傳送HTTP
1.httpconnection
textView = findViewById(R.id.text_view); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { new Thread(new Runnable() { @Override public void run() { HttpURLConnection connection = null; BufferedReader reader = null; try { URL url = new URL("http://www.baidu.com"); connection = (HttpURLConnection) url.openConnection(); connection.setRequestMethod("GET"); connection.setConnectTimeout(8000); connection.setReadTimeout(8000); InputStream in = connection.getInputStream(); reader = new BufferedReader(new InputStreamReader(in)); StringBuilder response = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { response.append(line); } showResponse(response.toString()); } catch (IOException e) { e.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } if (connection != null) { connection.disconnect(); } } } }).start(); } }); private void showResponse(final String response) { runOnUiThread(new Runnable() { @Override public void run() { textView.setText(response); } }); }
.xml中：
新增許可權控制，如上
2.OkHttp
.gradle中：
implementation 'com.squareup.okhttp3:okhttp:3.10.0'
java中：
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://www.baidu.com")
.build();
try {
Response response = client.newCall(request).execute();
String responseData = response.body().string();
showResponse(responseData);
} catch (IOException e) {
e.printStackTrace();
}
.xml中：
引入許可權控制，如上
3. xml解析
1.PULL
// 解析xml檔案
private void parseXMLWithPull(String xmlData) {
XmlPullParserFactory factory = null;
try {
factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
xmlPullParser.setInput(new StringReader(xmlData));
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT) {
String nodeName = xmlPullParser.getName();
switch (eventType) {
// 開始解析某個節點
case XmlPullParser.START_TAG: {
if ("id".equals(nodeName)) {
id = xmlPullParser.nextText();
} else if("name".equals(nodeName)) {
name = xmlPullParser.nextText();
} else if("version".equals(nodeName)) {
version = xmlPullParser.nextText();
}
break;
}
// 完成解析某個節點
case XmlPullParser.END_TAG: {
if ("app".equals(nodeName)) {
System.out.println("id is " + id);
System.out.println("name is " + name);
System.out.println("version is " + version);
}
break;
}
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.SAX
.java中：
繼承DefaultHandler類：
public class ContentHandler extends DefaultHandler {
private String nodeName;
private StringBuilder id;
private StringBuilder name;
private StringBuilder version;
/**
* 開始解析的時候呼叫
*/
@Override
public void startDocument() throws SAXException {
super.startDocument();
id = new StringBuilder();
name = new StringBuilder();
version = new StringBuilder();
}
/**
* 開始解析某個節點的時候呼叫
*/
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
super.startElement(uri, localName, qName, attributes);
// 記錄當前節點名稱
nodeName = localName;
}
/**
* 獲取節點內容的時候呼叫
*/
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
super.characters(ch, start, length);
// 根據當前節點名稱判斷將內容新增到哪個StringBuilder物件中
if ("id".equals(nodeName)) {
id.append(ch,start,length);
} else if ("name".equals(nodeName)) {
name.append(ch,start,length);
} else if ("version".equals(nodeName)) {
version.append(ch,start,length);
}
}
/**
* 完成某個節點的時候呼叫
*/
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
super.endElement(uri, localName, qName);
if ("app".equals(localName)) {
System.out.println("id is " + id.toString().trim());
System.out.println("name is " + name.toString().trim());
System.out.println("version is " + version.toString().trim());
// 最後要將StringBuilder清空掉,不然影響下一次內容讀取
id.setLength(0);
name.setLength(0);
version.setLength(0);
}
}
/**
* 完成整個xml解析的時候呼叫
*/
@Override
public void endDocument() throws SAXException {
super.endDocument();
}
}
java.activity中:
private void parseXMLWithSAX(String xmlData) {
SAXParserFactory factory = SAXParserFactory.newInstance();
try {
XMLReader xmlReader = factory.newSAXParser().getXMLReader();
ContentHandler handler = new ContentHandler();
// 將ContentHandler的例項設定到XMLReader中
xmlReader.setContentHandler(handler);
// 開始執行解析
xmlReader.parse(new InputSource(new StringReader(xmlData)));
} catch (Exception e) {
e.printStackTrace();
}
}
4. JSON解析
1.JSONObject
private void parseJSONWithJSONObject(String jsonData) {
try {
JSONArray jsonArray = new JSONArray(jsonData);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String id = jsonObject.getString("id");
String name = jsonObject.getString("name");
String version = jsonObject.getString("version");
System.out.println("id is " + id);
System.out.println("name is " + name);
System.out.println("version is " + version);
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.GSON
.gradle中：
implementation 'com.google.code.gson:gson:2.8.4'
java中：
新建App類，作為對映物件
java.Activity中：
private void parseJSONWithGSON(String jsonData) {
Gson gson = new Gson();
List<App> appList = gson.fromJson(jsonData, new TypeToken<List<App>>() {
}.getType());
for (App app:appList
) {
System.out.println("id is " + app.getId());
System.out.println("name is " +app.getName());
System.out.println("version is " +app.getVersion());
}
}