Question

我有一个JSON助手类。如果出现错误而不是强制关闭，我一直试图显示Toast消息。问题是，因为这是一个帮助类，它没有上下文，也不能显示Toast。任何人都可以帮助引导我如何传递Context吗？

 public class JSONfunction {



public static JSONObject getJSONfromURL(String url) {
    InputStream is = null;
    String result = "";
    JSONObject json = null;

    // HTTP Post
    try {

        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(url);
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();

    } catch (Exception e) {

        Log.e("JSONfunction", "Error converting internet " + e.toString());
    }

    // Convert Response to String
    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        result = sb.toString();
    } catch (Exception e) {
        Log.e("JSONfunction", "Error converting result " + e.toString());
    }

    try {
        json = new JSONObject(result);

    } catch (JSONException e) {
        Log.e("JSONfunction", "Error parsing data " + e.toString());
    }

    return json;
}



public static JSONArray getJSONArray(String string) {
    // TODO Auto-generated method stub
    return null;
}

public static String getString(String string) {
    // TODO Auto-generated method stub
    return null;
}
 }

Answer 1

刚刚为您的方法添加了一个上下文... public static JSONObject getJSONfromURL(String url, Context context) { Toast.makeText(context...);}，然后从一个Activity或其他上下文中调用它...来自一个活动：getJSONfromURL(url, this);，因为这可能不是UIThread，那么它将在一个线程或AsyncTask中，如果它在一个Activity中，你可以这样做：getJSONfromURL(url, MyHappyActivity.this);另外，考虑使用Application而不是Activity ...来自Activity的getApplicationContext（）会给你该上下文：getJSONfromURL(url, getApplicationContext());如果从活动中调用。

将Context传递给helper类以在Try / Catch中显示Toast

1 个答案: