Question

我是java和android编程的新手，并且通过遵循一些教程，我试图制作一个Android应用程序，必须向php页面发出Http请求以读取输出字符串。我在doInBackground方法中得到以下错误：

Multiple markers at this line
    - Exception MalformedURLException is not compatible with throws clause in 
     AsyncTask<Void,String,String>.doInBackground(Void[])
    - Exception IOException is not compatible with throws clause in AsyncTask<Void,String,String>.doInBackground(Void[])
    - Exception IOException is not compatible with throws clause in AsyncTask<Void,String,String>.doInBackground(Void[])
    - implements android.os.AsyncTask<java.lang.Void,java.lang.String,java.lang.String>.doInBackground
    - Exception MalformedURLException is not compatible with throws clause in 
     AsyncTask<Void,String,String>.doInBackground(Void[])

有什么想法吗？谢谢

这是MainActivity.java代码：

public class MainActivity extends Activity {

    Button button;
    TextView finalResult;

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

        @Override
        public String doInBackground(Void... v) throws IOException, MalformedURLException{


            try{
            URL url = new URL("http://myUrl");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            BufferedReader read = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line = read.readLine();
            String html = "";
            while (line != null){
                html += line;
                line = read.readLine();
            }
            return html;
            }
            catch(MalformedURLException ex){
                System.out.println(ex.getMessage());
                }
            catch(Exception ee){
                System.out.println(ee.getMessage());
                }
        }
        @Override
        public void onPreExecute(){
        }
        @Override
        public void onPostExecute(String result){
            finalResult.setText(result);
        }
}

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

        button = (Button) findViewById(R.id.asynkButton);
        finalResult = (TextView) findViewById(R.id.textView1);
        button.setOnClickListener(new View.OnClickListener(){
            @Override
               public void onClick(View view) {
                ConnessioneAsyncTask runner = new ConnessioneAsyncTask();
                runner.execute();
            }
        });
    }
}

Answer 1

doInBackground方法不会声明任何throws clause并且您正在尝试添加throws声明。您需要在代码中处理所有异常，而不是使用throws子句声明它。这是doInBackground方法的javadoc。因此，简而言之，您需要删除throws子句才能使其有效。

Android：AsyncTask和HttpConnection错误

1 个答案: