Question

我正在创建一个class来检查给定的URL是否有效，但我没有理解如何将此类调用到其他类中，因为在我的项目中，我必须检查每个班级的URL回复。我的代码是：`

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnected()) {
        MyTask task = new MyTask();
        task.execute();
    }
}

private class MyTask extends AsyncTask<Void, Void, Boolean> {

    @Override
    protected Boolean doInBackground(Void... params) {

        try {

            URL url = new URL("http://www.google.com");
            HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
            urlc.setConnectTimeout(10 * 1000);
            urlc.connect();
            if (urlc.getResponseCode() == 200) {
                Log.wtf("Connection", "Success !");
                return true;
            } else {
                return false;
            }
        } catch (MalformedURLException e1) {
            return false;
        } catch (IOException e) {
            return false;
        }
    }

    @Override
    protected void onPostExecute(Boolean result) {
        boolean bResponse = result;
    }
}

Answer 1

你快到了！

private class MyTask extends AsyncTask<Void, Void, Boolean> {
    private URL mUrl;

    public MyTask(URL url) {
        mUrl = url;
    }

    @Override
    protected Boolean doInBackground(Void... params) {
        try {
            HttpURLConnection urlc = (HttpURLConnection) mUrl.openConnection();
            urlc.setConnectTimeout(10 * 1000);
            urlc.connect();
            if (urlc.getResponseCode() == 200) {
                Log.wtf("Connection", "Success !");
                return true;
            } else {
                return false;
            }
        } catch (MalformedURLException e1){
            return false;
        } catch (IOException e) {
            return false;
        }
    }
}

当您需要检查责任时：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnected()) {
        URL url = new URL("http://www.google.com");
        MyTask task = new MyTask(url){
            @Override
            protected void onPostExecute(Boolean result) {
               if (result) {
                   // Do your work here
               }
            }
        };
        task.execute();
    }
}

Answer 2

首先，您可以为api调用创建一个常见的异步类：

public class BackgroundNetwork extends AsyncTask<Void, String, Void> {

    private ProgressDialog progressDialog;
    Context context;


    public BackgroundNetwork(Context activity) {
        context = activity;
        progressDialog = new ProgressDialog(context);
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        if(progressDialog.isShowing()){
            progressDialog.dismiss();
        }
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog.show();
        progressDialog.setCancelable(false);
    }

    @Override
    protected Void doInBackground(Void... params) {
        return null;
    }

}

其次，您可以在活动中使用async类，并调用如下：

new BackgroundNetwork(context){
            protected Void doInBackground(Void... params) {
                checkUrl();
                return null;
            };

            protected void onPostExecute(Void result) {

            };
        }.execute();

private checkUrl(){
        URL myurl = new URL(url);
        URLConnection connection = myurl.openConnection();
        connection.setConnectTimeout(30 * 1000); // optional depends on you
        HttpURLConnection httpConnection = (HttpURLConnection) connection;
        int responseCode = -1;
        try {
            responseCode = httpConnection.getResponseCode();
        } catch (Exception e1) {                    
                throw e1;                   
        }
        if (responseCode == HttpURLConnection.HTTP_OK) {
              //connection is OK and do what you want
              //...
        }
        else
        {
              //connection is not OK
              httpConnection.disconnect();
        }
}

如何在Android中检查特定网址是否有效？

2 个答案: