實現android非同步呼叫WEB API的方法,並實現回調

上一篇文章 實現android非同步呼叫WEB API的方法 在做完了事之後沒有告訴主線程，我在這裡改進一下讓他在完事後可以告訴主線程，這樣就比較實用了

首先定義一個介面並簡單實現一下,onTaskCompleted 就是我們將來完成非同步後腰回調的方法：

public interface OnTaskCompleted{    void onTaskCompleted(JSONObject result);}public class Callback implements OnTaskCompleted{    @Override    public void onTaskCompleted(JSONObject result) {        // do something with result here!    }}

然後修改我的非同步呼叫的代碼

public class ApiCall extends AsyncTask {    private OnTaskCompleted listener;    private String result;    public ApiCall(OnTaskCompleted listener){        this.listener=listener;    }    protected Long doInBackground(URL... urls) {        int count = urls.length;        long totalSize = 0;        StringBuilder resultBuilder = new StringBuilder();        for (int i = 0; i < count; i++) {            try {                // Read all the text returned by the server                InputStreamReader reader = new InputStreamReader(urls[i].openStream());                BufferedReader in = new BufferedReader(reader);                String resultPiece;                while ((resultPiece = in.readLine()) != null) {                    resultBuilder.append(resultPiece);                }                in.close();             } catch (MalformedURLException e) {                 e.printStackTrace();             } catch (IOException e) {                 e.printStackTrace();             }             // if cancel() is called, leave the loop early             if (isCancelled()) {                 break;             }         }         // save the result         this.result = resultBuilder.toString();         return totalSize;     }    protected void onProgressUpdate(Integer... progress) {        // update progress here    }    // called after doInBackground finishes    protected void onPostExecute(Long result) {        Log.v("result, yay!", this.result);        // put result into a json object        try {            JSONObject jsonObject = new JSONObject(this.result);            // call callback            listener.onTaskCompleted(jsonObject);        } catch (JSONException e) {            e.printStackTrace();        }    }}

調用就很簡單了

URL url = null;try {    url = new URL("http://127.0.0.0/search");} catch (MalformedURLException e) {    e.printStackTrace();}new ApiCall(new Callback()).execute(url);