如何确定变量的范围以用作公共静态最终字符串？

Question

This code is in the onCreate and reading an IP address from a txt file:

DefaultHttpClient httpclient = new DefaultHttpClient();
try {
HttpGet httppost = new HttpGet("http://readdeo.uw.hu/uploads/IP.txt");
HttpResponse response;

    response = httpclient.execute(httppost);

        HttpEntity ht = response.getEntity();

        BufferedHttpEntity buf = new BufferedHttpEntity(ht);

        InputStream is = buf.getContent();


        BufferedReader r = new BufferedReader(new InputStreamReader(is));

        StringBuilder total = new StringBuilder();
        String line;
        while ((line = r.readLine()) != null) {
            total.append(line.trim());
        //    txv.setText(total);
        }} catch (ClientProtocolException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

How can i make it to use the "total" StringBuilder variable in this String for other methods?

private static final String SERVER_IP = "IP_ADDRESS";

Answer 1

You can add the IP address as a field in some class and then set its value:

class YourClass {
    String mIpAddress;

    ...

    void yourMethod() {
        ...
        ipAddress = total;
    }
}

And then you should think about what happens when somewhere else someone accesses mIpAddress before it is initialized.

Answer 2

you can fix this issue by handler.

first, you can use below code, such as

private int static final RESULT_IP_ADDRESS = 100;

Message msg = mHandler.obtainMessage(RESULT_IP_ADDRESS);
msg.getData().putString("IP_ADDRESS_KEY", total.toString());
msg.sendToTarget();

class MyHandler extends Handler{
    @override
    public void handleMessage(Message msg) {
        switch(msg.what) {
            case RESULT_IP_ADDRESS:
                String total = msg.getData().getString("IP_ADDRESS_KEY");
                // call your method with total data
                break;
            default:
                break;
        }
    }
}