WebView的用法

1.使用webView简单加载网页

*该操作需要在Manifest中注册INTERNET权限

<uses-permission android:name="android.permission.INTERNET" />

• setJavaScriptEnabled(true) : 使WebView支持JS脚本
• setWebViewClient(new WebViewClient)：设置一个实例，在webView中显示网页内容，而非在系统浏览器。

public class WebViewTestActivity extends AppCompatActivity {
    private WebView mWebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_web_view_test);
        init();
    }

    private void init() {
        mWebView = findViewById(R.id.web_view);
        mWebView.getSettings().setJavaScriptEnabled(true);
        mWebView.setWebViewClient(new WebViewClient());
        mWebView.loadUrl("http://www.baidu.com");
    }
}

使用HttpURLConnection

    /**
     * this function should run in a Background Tread
     */
    private void generateRequest(){
        BufferedReader br = null;
        HttpURLConnection conn = null;
        try {
            URL url = new URL("http://www.baidu.com");
            conn = (HttpURLConnection) url.openConnection();
            //Http请求主要有两种：GET和POST，GET从服务器获取数据，POST可以提交数据给服务器
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(8000);
            conn.setReadTimeout(8000);
            InputStream input = conn.getInputStream();

            //read input stream from opened conn
            br = new BufferedReader(new InputStreamReader(input));
            StringBuilder response = new StringBuilder();
            String line;
            while ((line = br.readLine()) != null) {
                response.append(line);
            }
        }  catch (IOException e){
            e.printStackTrace();
        } finally {
            try{
                if(br != null){
                    br.close();
                }
                if(conn != null){
                    conn.disconnect();
                }
            } catch (IOException e){
                e.printStackTrace();
            }
        }
    }

使用OkHttp

OkHttp是一个Android的开源项目，可以用来替代原生的HttpURLConnection来进行网络操作。
下面是GET 和POST request的使用方法：

    public void generateOkHttpRequest() {
        OkHttpClient client = new OkHttpClient();

        //踩坑：这里的Request后面不要加括号，Builder是Request里面的静态内部类，加了语法就错了

        //get请求
        Request getRequest = new Request.Builder() //the default method is GET
                .url("http://www.baidu.com")
                .build();
        try {
            Response response = client.newCall(getRequest).execute();
            String responseString = response.body().string();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //post请求
        RequestBody requestBody = new FormBody.Builder()
                .add("name", "lyh")
                .add("password", "admin")
                .build();
        Request postRequest = new Request.Builder()
                .url("http:/www.baidu.com")
                .post(requestBody)
                .build();
        try {
            Response response = client.newCall(postRequest).execute();
            String responseString = response.body().string();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }