//异步任务处理    //创建内部类,来实现网络异步请求    //新建内部类 继承 AsyncTask    @SuppressLint("StaticFieldLeak")    class RequestNetworkDataTask extends AsyncTask
    
      {        @Override        protected void onPreExecute() {            super.onPreExecute();            textView.setText("加载中");            //主线程        }        @Override        protected String doInBackground(String[] strings) {            String result = requestData(strings[0]);            return result;            //子线程,需要异步执行的命令在此执行        }        @Override        protected void onPostExecute(String s) {            super.onPostExecute(s);            textView.setText(s);            //主线程            //异步代码处理完后,在主线程中进行进一步操作        }    }
    

在需要调用这个自定义内部类的地方使用以下代码

String url = getEditTextUrl();                new RequestNetworkDataTask().execute(url);

下面是通过EditText 获取输入的网址

通过点击Button 在下方的TextView中显示网址对应的网站源码

public class NetworkActivity extends AppCompatActivity implements View.OnClickListener {    private EditText editText;    private Button btn;    private TextView textView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_network);        initView();        btn.setOnClickListener(this);    }    private void initView() {        editText = findViewById(R.id.act_network_url_et);        btn = findViewById(R.id.act_network_getNet_btn);        textView = findViewById(R.id.act_network_show_tv);    }    @Override    public void onClick(View view) {        switch (view.getId()) {            case R.id.act_network_getNet_btn:                String url = getEditTextUrl();                new RequestNetworkDataTask().execute(url);                break;        }    }    private String getEditTextUrl() {        return editText != null ? editText.getText().toString() : "";    }    private String requestData(String urlString) {        try {            URL url = new URL(urlString);            //打开Url            HttpURLConnection connection = (HttpURLConnection) url.openConnection();            //设置超时时间            connection.setConnectTimeout(5000);            //设置请求方法            connection.setRequestMethod("GET");            //开始请求            connection.connect();            int response = connection.getResponseCode();            //请求的消息            String reponseMessage = connection.getResponseMessage();            InputStream inputStream = connection.getInputStream();            Reader reader = new InputStreamReader(inputStream, "UTF-8");            char[] buffer = new char[1024 * 8];            reader.read(buffer);            String content = new String(buffer);            return content;        } catch (IOException e) {            e.printStackTrace();        }        return null;    }    //异步任务处理    //创建内部类,来实现网络异步请求    @SuppressLint("StaticFieldLeak")    class RequestNetworkDataTask extends AsyncTask
    
      {        @Override        protected void onPreExecute() {            super.onPreExecute();            textView.setText("加载中");            //主线程        }        @Override        protected String doInBackground(String[] strings) {            String result = requestData(strings[0]);            return result;        }        @Override        protected void onPostExecute(String s) {            super.onPostExecute(s);            textView.setText(s);            //主线程        }    }}