如何在可选择的时间内多次执行 asynctask？

Question

我在 mainactivty 上有 7 个单选按钮，每个按钮都需要不同的时间（1 分钟、5 分钟、10 分钟……），我有异步任务，我正在从服务器（php）调用图片，所以我想要当用户选择第一个单选按钮（1 分钟）时，异步任务每 1 分钟执行一次，我尝试了 radiobutton.ischecked 和 puttet 处理程序，但没有成功 我的服务器正在工作，我正在收到响应，但我无法使用此设置执行异步任务来设置壁纸，它查看了我的代码

  TextView txt;
Button btn;
ImageView imageView;
String forecastJsonStr;
RadioButton rd1,rd2,rd3,rd4,rd5,rd6,rd7;
Runnable mHandlerTask;
Handler mHandler;
RadioGroup radioGroup;

private final static int INTERVAL = 4000  ; //1 min
private final static int INTERVAL2 = 1000 * 60 * 5; // 5 min
private final static int INTERVAL3 = 1000 * 60 * 10; // 10 min
private final static int INTERVAL4 = 1000 * 60 * 15; // 15 min
private final static int INTERVAL5 = 1000 * 60 * 30 ; // 30 min
private final static int INTERVAL6 = 1000 * 60 * 60; // 1 hour
private final static int INTERVAL7 = 1000 * 60 * 1440; // 1 day

private final String hostName = "http://555.555.555.555";
private final String hostRequestName = "/yay.php";
private final String hostWallpaperName = "/wallpaper/";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    txt = (TextView) findViewById(R.id.textView);
    imageView = (ImageView) findViewById(R.id.imageView);
    rd1 = (RadioButton)findViewById(R.id.radioButton) ;
    rd2 = (RadioButton)findViewById(R.id.radioButton2) ;
    rd3 = (RadioButton)findViewById(R.id.radioButton3) ;
    rd4 = (RadioButton)findViewById(R.id.radioButton4) ;
    rd5 = (RadioButton)findViewById(R.id.radioButton5) ;
    rd6 = (RadioButton)findViewById(R.id.radioButton6) ;
    rd7 = (RadioButton)findViewById(R.id.radioButton7) ;
    radioGroup = (RadioGroup)findViewById(R.id.radiogroup) ;
    mHandler = new Handler();
    btn = (Button) findViewById(R.id.button);

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
                if(rd1.isChecked()) {
                    mHandlerTask = new Runnable() {
                        @Override
                        public void run() {
                            new WallpaperData().execute();
                            mHandler.postDelayed(mHandlerTask, INTERVAL);
                            startRepeatingTask();
                        }
                    };


                }
        }
        void startRepeatingTask()
        {
            mHandlerTask.run();
        }

    });
}


private class WallpaperData extends AsyncTask<Void, Void, String> {

    @Override
    protected String doInBackground(Void... params) {

        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;


        try {

            URL url = new URL("http://555.555.555.555/yay.php");

            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("POST");
            urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            urlConnection.setDoInput(true);
            urlConnection.setDoOutput(true);
            urlConnection.connect();
            DataOutputStream wr = new DataOutputStream(
                    urlConnection.getOutputStream());
            wr.write("method=get_random_wallpaper".getBytes());
            wr.flush();
            wr.close();

            InputStream inputStream = urlConnection.getInputStream();
            StringBuffer buffer = new StringBuffer();
            if (inputStream == null) {
                return null;
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));

            String line;
            while ((line = reader.readLine()) != null) {

                buffer.append(line + "\n");
                Log.d("hey", buffer.toString());

            }

            if (buffer.length() == 0) {
                return null;
            }
            forecastJsonStr = buffer.toString();

            return forecastJsonStr;
        } catch (IOException e) {
            Log.e("PlaceholderFragment", "Error ", e);

            return null;
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (final IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Override
    protected void onPostExecute(final String forecastJsonStr) {

        txt.setText(forecastJsonStr);

        Thread thread = new Thread(new Runnable() {

            @Override
            public void run() {

                            WallpaperManager wallpaperManager = WallpaperManager.getInstance(getApplicationContext());
                            try {
                                Bitmap result = Picasso.with(getBaseContext())
                                        .load(hostName + hostWallpaperName + forecastJsonStr)
                                        .get();
                                wallpaperManager.setBitmap(result);
                            } catch (IOException ex) {
                                ex.printStackTrace();
                            }

                        }
        });
        thread.start();

        super.onPostExecute(forecastJsonStr);


    }

}
 }

Answer 1

创建一个变量来存储选择间隔。将mHandlerTask 和startRepeatingTask 方法移到onCreate 之外。在onClick 内部调用startRepeatingTask 方法。

请看下面的代码，

private final static int SELECTED_INTERVAL = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    ...

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(rd1.isChecked()) {
                SELECTED_INTERVAL = INTERVAL;
            } else if (rd2.isChecked()) {
                SELECTED_INTERVAL = INTERVAL2;
            }
            stopRepeatingTask();
            startRepeatingTask();
        }
    });
}

void startRepeatingTask() {
    mHandlerTask.run();
}

void stopRepeatingTask() {
    mHandler.removeCallbacks(null);
}

Runnable mHandlerTask = new Runnable() {
    @Override
    public void run() {
        new WallpaperData().execute();
        mHandler.postDelayed(mHandlerTask, SELECTED_INTERVAL);
    }
};

@Override
public void onDestroy() {
    super.onDestroy();
    stopRepeatingTask();
}