java - JSON 和内存问题

Question

我正在尝试从网络加载大量数据到我的 android 应用程序，但我一直收到此错误:

07-18 10:16:00.575: E/AndroidRuntime(30117): java.lang.OutOfMemoryError: [memory exhausted]

并且已经阅读了很多关于 JSON 的内容。我找到了一些解决方案，但没有任何帮助。

这是我的代码:

public class HistoricoAdapter extends BaseAdapter {
    private Context ctx;
    JSONArray jsonArray;

    public HistoricoAdapter(Context ctx) {
        this.ctx = ctx;

        String readHttp = readHttp();

        try {
            // transforma a string retornada pela função readHttp() em array
            jsonArray = new JSONArray(readHttp);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public String readHttp() {

        // Acessa a URL que retorna uma string com  os dados do banco
        StringBuilder builder = new StringBuilder();
        HttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet("some url");
        try {
            HttpResponse response = client.execute(httpGet);
            StatusLine statusLine = response.getStatusLine();

            int statusCode = statusLine.getStatusCode();
            if (statusCode == 200) {
                HttpEntity entity = response.getEntity();
                InputStream content = entity.getContent();
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(content));
                String line;
                while ((line = reader.readLine()) != null) {
                    builder.append(line);
                }
            } else {
                Log.e(this.toString(), "Erro ao ler JSON!");
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return builder.toString();
    }

    public int getCount() {
        return jsonArray.length();
    }
    public boolean isEmpty(){

        if(jsonArray.toString().isEmpty()){
            return true;
        }
        else {
            return false;
        }
    }

    public Object getItem(int position) {
        JSONObject ob = null;
        try {
            ob = jsonArray.getJSONObject(position);
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return ob;
    }

    public long getItemId(int arg0) {
        return 0;
    }

    public View getView(int position, View view, ViewGroup arg2) {

        LayoutInflater layout = (LayoutInflater) ctx
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View v = layout.inflate(R.layout.listar_compromisso, null);

        try {
            JSONObject obj = (JSONObject) getItem(position);



        } catch (Exception ex) {

        }

        return v;
    }
}

谁能预测我为什么会收到此错误？

Answer 1

如果您收到此错误，则您的 JSON 必须太大而无法缓冲到内存中。

问题是org.json太基础了，无法处理。

您需要一个高级库来流式传输响应，例如 GSON 或 Jackson .

• GSON - Streaming
• Jackson - Processing model: Streaming API