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

• WebViewClient

辅助WebView处理各种通知与请求事件

• WebSettings

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

实例

• 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

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()

• 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() {

        //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

标签：String,url,connection,OkHttp,new,Android,WebView,view
来源： https://blog.csdn.net/Qricis/article/details/122452076