WebView
brief introduction
- It is generally used to load some network interfaces
- Android is a high-performance browser with built-in webkit kernel, and WebView is a control encapsulated on this basis. WebView can be simply regarded as a browser control that can be nested on the interface!
method
- WebChromeClient
Assist WebView in handling Javascript dialog boxes, website icons, website title s, loading progress, etc
| method | effect |
| onJsAlert(WebView view,String url,String message,JsResult result) | Handling Alert dialog in Js |
| onJsConfirm(WebView view,String url,String message,JsResult result) | Process the Confirm dialog in Js |
| onJsPrompt(WebView view,String url,String message,String defaultValue,JsPromptResult result) | Process Prompt dialog in Js |
| onProgressChanged(WebView view,int newProgress) | Called when the loading progress bar changes |
| onReceivedIcon(WebView view, Bitmap icon) | Get the icon of the web page |
| onReceivedTitle(WebView view, String title) | Get the title of the page |
- WebViewClient
Assist WebView to handle various notification and request events
| method | effect |
| onPageStared(WebView view,String url) | Notify the main program that the web page starts loading |
| onPageFinished(WebView view,String url,Bitmap favicon) | Notify the main program that the web page is loaded |
| doUpdateVisitedHistory(WebView view,String url,boolean isReload) | Update history |
| onLoadResource(WebView view,String url) | Notifies the main program that WebView is about to load the resource with the specified url |
| onScaleChanged(WebView view,float oldScale,float newScale) | Called when the zoom of the ViewView changes |
| shouldOverrideKeyEvent(WebView view,KeyEvent event) | Controls whether WebView processes the key pressing time. If true is returned, WebView does not process it, and if false is returned, WebView processes it |
| shouldOverrideUrlLoading(WebView view,String url) | Controls the processing of newly loaded URLs. Returning true means that the main program does not process WebView. Returning false means that WebView will process it |
| onReceivedError(WebView view,int errorCode,String description,String failingUrl) | Called when an unrecoverable error message is encountered |
- WebSettings
WebView related configuration settings, such as setJavaScriptEnabled() setting whether JS script execution is allowed
| method | effect |
| getSettings() | Returns a WebSettings object to control the property setting of WebView |
| loadUrl(String url) | Loads the specified Url |
| loadData(String data,String mimeType,String encoding) | Load the specified data into WebView Using "data:" as the tag header, this method cannot load network data Where mimeType is the data type, such as textml, image / jpeg Encoding is the encoding method of characters |
| loadDataWithBaseURL(String baseUrl, String data, String mimeType, String encoding, String historyUrl) | More powerful than loadData above |
| setWebViewClient(WebViewClient client) | Specify a WebViewClient object for WebView WebViewClient can assist WebView in handling various notifications, requests and other events. |
| setWebChromeClient(WebChromeClient client) | Specify a WebChromeClient object for WebView. WebChromeClient is specially used to assist WebView in processing js dialog boxes, website title s, website icons, loading progress bars, etc |
example
- xml
<WebView android:id="@+id/web_view" android:layout_width="409dp" android:layout_height="729dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" />
- MainActivity
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView webView = findViewById(R.id.web_view);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebViewClient(new WebViewClient());
webView.loadUrl("https://www.baidu.com");
}
}- Manifest
On Android 9 After 0, the url does not support plaintext format, so either encrypt https, add a line of Android: usesclleartexttraffic = "true" in the application (but not), or reduce the SDK version
<uses-permission android:name="android.permission.INTERNET"/> <application android:allowBackup="true" android:usesCleartextTraffic="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application>
- Download address
DoSomeAndroidTest/WebView at main · qricis/DoSomeAndroidTest · GitHub
Network request mode
- In the past, there were generally two ways to send Http requests on Android: HttpURLConnection and HttpClient. However, due to the excessive number of API s of HttpClient, Android 6 0 has been completely removed from the system
// HttpURLConnection
// Get the instance
URL url = new URL("http://baidu.com");
HttpUriConnection connection = (HttpURLConnection) url.openConnection();
// Set the method used for the request (get / post). Get indicates that you want to obtain data from the server, and post indicates that you want to submit data to the server
connection.setRequestMethod("GET")
// connection timed out
connection.setConnectTimeout(8000);
// Number of milliseconds read timeout
connection.setReadTimeout(8000);
// Gets the input stream returned by the server
InputStream in = connection.getInputStream();
// Call the disconnect() method to close the http connection
connection.disconnect()- xml
<Button android:id="@+id/send_request" android:layout_width="163dp" android:layout_height="0dp" android:text="@string/sendrequest" android:onClick="sendResquest" app:layout_constraintHeight_default="percent" app:layout_constraintHeight_percent="0.08" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> <ScrollView android:layout_width="match_parent" android:layout_height="0dp" android:layout_marginTop="1dp" app:layout_constraintHeight_default="percent" app:layout_constraintHeight_percent="0.9" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.0" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@+id/send_request" app:layout_constraintVertical_bias="1.0"> <TextView android:id="@+id/response_text" android:layout_width="match_parent" android:layout_height="wrap_content" /> </ScrollView>
- Manifest
<uses-permission android:name="android.permission.INTERNET"/> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application>
- MainActivity
public class MainActivity extends AppCompatActivity {
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
responseText = findViewById(R.id.response_text);
}
public void sendResquest(View view) {
sendRequestWithHttpURLConnection();
}
private void sendRequestWithHttpURLConnection() {
//Start a thread to initiate a network request
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("https://www.baidu.com");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
//How to submit data to the server
/*connection.setRequestMethod("POST");
DataOutputStream out = new DataOutputStream(connection.getOutputStream());
out.writeBytes("username=admin&password=123456");*/
//Read the obtained input stream
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (Exception 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() {
//Perform UI operations here and display the results on the interface
responseText.setText(response);
}
});
}
}OkHttp
- build.gradle
implementation 'com.squareup.okhttp3:mockwebserver:4.8.1'
- MainActivity
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://www.baidu.com")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
showResponse(responseData);
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}- Upgraded version (parsing data)
private void parseXMLWithPull(String xmlData) {
try {
XmlPullParserFactory 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) {
//Start parsing a node
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;
}
//Finish parsing a node
case XmlPullParser.END_TAG:{
if ("app".equals(nodeName)) {
Log.d("MainActivity","id is " + id);
Log.d("MainActivity","name is " + name);
Log.d("MainActivity","version is " + version);
}
break;
}
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void parseXMLWithSAX(String xmlData) {
try {
SAXParserFactory factory = SAXParserFactory.newInstance();
XMLReader xmlReader = factory.newSAXParser().getXMLReader();
ContentHandler handler = new ContentHandler();
//Set the instance of ContentHandler to XMLReader
xmlReader.setContentHandler(handler);
//Start parsing
xmlReader.parse(new InputSource(new StringReader(xmlData)));
} catch (Exception e) {
e.printStackTrace();
}
}
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");
Log.d("MainActivity","id is " + id);
Log.d("MainActivity","name is " + name);
Log.d("MainActivity","version is " + version);
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void parseJSONWithGson(String jsonData) {
Gson gson = new Gson();
List<App> appList = gson.fromJson(jsonData,new TypeToken<List<App>>(){}.getType());
for (App app : appList) {
Log.d("MainActivity","id is " + app.getId());
Log.d("MainActivity","name is " + app.getName());
Log.d("MainActivity","version is " + app.getVersion());
}
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
//Perform UI operations here and display the results on the interface
responseText.setText(response);
}
});
}Download address
DoSomeAndroidTest/NetworkTest at main · qricis/DoSomeAndroidTest · GitHub