android - 将 Context 传递给辅助类以在 Try/Catch 时显示 Toast

Question

我有一个 JSON 帮助程序类。如果出现错误，我一直在尝试显示 Toast 消息，而不是强制关闭它。问题是，由于这是一个帮助类，它没有上下文并且不能显示 Toast。任何人都可以帮助引导我朝着正确的方向前进，了解如何传递 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

刚刚在您的方法中添加了一个 Context...public static JSONObject getJSONfromURL(String url, Context context) { Toast.makeText(context...); 然后从 Activity 中调用它或其他上下文...来自 Activity :getJSONfromURL(url, this); 因为这可能不会在 UIThread 中完成，所以它将在线程或 AsyncTask 中，如果它在Activity，你可以这样做:getJSONfromURL(url, MyHappyActivity.this); 另外，考虑使用 Application 而不是 Activity ... Activity 的 getApplicationContext() 会给你那个上下文:getJSONfromURL(url, getApplicationContext()); 如果从 Activity 中调用。