Android基础之WebView | 网络请求方式 | HttpURLConnection | OkHttp | 带实例

2023-10-22 17:13:46

WebView

简介

一般用于加载一些网络界面
Android内置webkit内核的高性能浏览器,而WebView则是在这个基础上进行封装后的一个控件,WebView直译网页视图,我们可以简单的看作一个可以嵌套到界面上的一个浏览器控件！

方法

WebChromeClient

辅助WebView处理Javascript的对话框、网站图标、网站title、加载进度等

方法	作用
onJsAlert(WebView view,String url,String message,JsResult result)	处理Js中的Alert对话框
onJsConfirm(WebView view,String url,String message,JsResult result)	处理Js中的Confirm对话框
onJsPrompt(WebView view,String url,String message,String defaultValue,JsPromptResult result)	处理Js中的Prompt对话框
onProgressChanged(WebView view,int newProgress)	当加载进度条发生改变时调用
onReceivedIcon(WebView view, Bitmap icon)	获得网页的icon
onReceivedTitle(WebView view, String title)	获得网页的标题

WebViewClient

辅助WebView处理各种通知与请求事件

方法	作用
onPageStared(WebView view,String url)	通知主程序网页开始加载
onPageFinished(WebView view,String url,Bitmap favicon)	通知主程序,网页加载完毕
doUpdateVisitedHistory(WebView view,String url,boolean isReload)	更新历史记录
onLoadResource(WebView view,String url)	通知主程序WebView即将加载指定url的资源
onScaleChanged(WebView view,float oldScale,float newScale)	ViewView的缩放发生改变时调用
shouldOverrideKeyEvent(WebView view,KeyEvent event)	控制webView是否处理按键时间,如果返回true,则WebView不处理,返回false则处理
shouldOverrideUrlLoading(WebView view,String url)	控制对新加载的Url的处理,返回true,说明主程序处理WebView不做处理,返回false意味着WebView会对其进行处理
onReceivedError(WebView view,int errorCode,String description,String failingUrl)	遇到不可恢复的错误信息时调用

WebSettings

WebView相关配置的设置，比如setJavaScriptEnabled()设置是否允许JS脚本执行

方法	作用
getSettings()	返回一个WebSettings对象,用来控制WebView的属性设置
loadUrl(String url)	加载指定的Url
loadData(String data,String mimeType,String encoding)	加载指定的Data到WebView中.使用"data:"作为标记头,该方法不能加载网络数据.其中mimeType为数据类型如:textml,image/jpeg. encoding为字符的编码方式
loadDataWithBaseURL(String baseUrl, String data, String mimeType, String encoding, String historyUrl)	比上面的loadData更加强大
setWebViewClient(WebViewClient client)	为WebView指定一个WebViewClient对象.WebViewClient可以辅助WebView处理各种通知,请求等事件。
setWebChromeClient(WebChromeClient client)	为WebView指定一个WebChromeClient对象,WebChromeClient专门用来辅助WebView处理js的对话框,网站title,网站图标,加载进度条等

实例

<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

在Android9.0之后，url不支持明文格式，所以要么进行加密https，要么在application里添加一行android:usesCleartextTraffic="true"(但是也不行)，或者降低SDK版本

<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>

下载地址

DoSomeAndroidTest/WebView at main · qricis/DoSomeAndroidTest · GitHub

网络请求方式

在过去，Android上发送Http请求一般有两种方式：HttpURLConnection和HttpClient，但是由于HttpClient的API数量过多，在Android6.0的系统中，被完全移除了

// HttpURLConnection

// 获取该实例
URL url = new URL("http://baidu.com");
HttpUriConnection connection = (HttpURLConnection) url.openConnection();

// 设置请求所用的方法(get/post),get表示希望从服务器获取数据，post表示希望提交数据给服务器
connection.setRequestMethod("GET")

// 连接超时
connection.setConnectTimeout(8000);

// 读取超时的毫秒数
connection.setReadTimeout(8000);

// 获取服务器返回的输入流
InputStream in = connection.getInputStream();

// 调用disconnect()方法关闭该http连接
connection.disconnect()

<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() {

        //开启线程来发起网络请求
        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();

                    //向服务器提交数据的写法
                    /*connection.setRequestMethod("POST");
			                    DataOutputStream out = new DataOutputStream(connection.getOutputStream());
			                    out.writeBytes("username=admin&password=123456");*/

                    //对获取到的输入流进行读取
                    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() {
                //在这里进行UI操作，将结果显示在界面上
                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();
}

升级版(解析数据)

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) {
                    //开始解析某个节点
                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;
                }
                    //完成解析某个节点
                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();
        //将ContentHandler的实例设置到XMLReader中
        xmlReader.setContentHandler(handler);
        //开始执行解析
        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() {
            //在这里进行UI操作，将结果显示在界面上
            responseText.setText(response);
        }
    });
}

下载地址

DoSomeAndroidTest/NetworkTest at main · qricis/DoSomeAndroidTest · GitHub

码农公寓

WebView

简介

方法

实例

网络请求方式

OkHttp

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