Android：在哪里以及如何自动刷新列表视图（我有刷新功能）
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【中文标题】Android：在哪里以及如何自动刷新列表视图（我有刷新功能）【英文标题】：Android: Where and how to auto refresh listview (I have the refresh function) 【发布时间】：2015-09-11 22:47:25 【问题描述】：这是我的 MainActivity，我真的需要帮助来创建一个每分钟自动刷新列表视图的函数
在我的 MainActivity 我有这个代码：
//This method is called when swipe refresh is pulled down
@Override
public void onRefresh()
fetchOrders();
我已经阅读了一些关于处理程序的文章，我得说我不知道将处理程序的代码放在哪里，因此如果你能帮我发布我的完整 MainActivity 以及额外的所需代码，那就是不胜感激
提前致谢！
public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener
private int mInterval = 5000; // 5 seconds by default, can be changed later
private Handler mHandler;
private String TAG = MainActivity.class.getSimpleName();
private String URL = "http://troyka.esy.es/troyka/orders.php";
private SwipeRefreshLayout swipeRefreshLayout;
private ListView listView;
private SwipeListAdapter adapter;
private List<Order> orderList;
// initially offset will be 0, later will be updated while parsing the json
private int offSet = 0;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView);
//RelativeLayout.LayoutParams layout_description = new RelativeLayout.LayoutParams(50,10);
//Rl.setLayoutParams(layout_description);
swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
orderList = new ArrayList<>();
adapter = new SwipeListAdapter(this, orderList);
listView.setAdapter(adapter);
swipeRefreshLayout.setOnRefreshListener(this);
/**
* Showing Swipe Refresh animation on activity create
* As animation won't start on onCreate, post runnable is used
*/
swipeRefreshLayout.post(new Runnable()
@Override
public void run()
swipeRefreshLayout.setRefreshing(true);
fetchOrders();
);
mHandler = new Handler();
startRepeatingTask();
Runnable mStatusChecker = new Runnable()
@Override
public void run()
//updateStatus(); //this function can change value of mInterval.
mHandler.postDelayed(mStatusChecker, mInterval);
;
void startRepeatingTask()
mStatusChecker.run();
void stopRepeatingTask()
mHandler.removeCallbacks(mStatusChecker);
/**
* This method is called when swipe refresh is pulled down
*/
@Override
public void onRefresh()
fetchOrders();
/**
* Fetching movies json by making http call
*/
private void fetchOrders()
// showing refresh animation before making http call
swipeRefreshLayout.setRefreshing(true);
// appending offset to url
String url = URL + offSet;
// Volley's json array request object
JsonArrayRequest req = new JsonArrayRequest(url,
new Response.Listener<JSONArray>()
@Override
public void onResponse(JSONArray response)
Log.d(TAG, response.toString());
if (response.length() > 0)
// looping through json and adding to order list
for (int i = 0; i < response.length(); i++)
try
JSONObject orderObj = response.getJSONObject(i);
int rank = orderObj.getInt("rank");
String title = orderObj.getString("title");
Order m = new Order(rank, title);
orderList.add(0, m);
// updating offset value to highest value
if (rank >= offSet)
offSet = rank;
catch (JSONException e)
Log.e(TAG, "JSON Parsing error: " + e.getMessage());
adapter.notifyDataSetChanged();
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
, new Response.ErrorListener()
@Override
public void onErrorResponse(VolleyError error)
Log.e(TAG, "Server Error: " + error.getMessage());
Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
);
// Adding request to request queue
MyApplication.getInstance().addToRequestQueue(req);
【问题讨论】：
【参考方案1】：您可以通过向 Handler 添加延迟任务来做到这一点。完整代码如下：
public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener
private int mInterval = 5000; // 5 seconds by default, can be changed later
private Handler mHandler;
private String TAG = MainActivity.class.getSimpleName();
private String URL = "http://troyka.esy.es/troyka/orders.php";
private SwipeRefreshLayout swipeRefreshLayout;
private ListView listView;
private SwipeListAdapter adapter;
private List<Order> orderList;
// initially offset will be 0, later will be updated while parsing the json
private int offSet = 0;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView);
//RelativeLayout.LayoutParams layout_description = new RelativeLayout.LayoutParams(50,10);
//Rl.setLayoutParams(layout_description);
swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
orderList = new ArrayList<>();
adapter = new SwipeListAdapter(this, orderList);
listView.setAdapter(adapter);
swipeRefreshLayout.setOnRefreshListener(this);
/**
* Showing Swipe Refresh animation on activity create
* As animation won't start on onCreate, post runnable is used
*/
swipeRefreshLayout.post(new Runnable()
@Override
public void run()
swipeRefreshLayout.setRefreshing(true);
fetchOrders();
);
mHandler = new Handler();
startRepeatingTask();
Runnable mStatusChecker = new Runnable()
@Override
public void run()
//updateStatus(); //this function can change value of mInterval.
mHandler.postDelayed(mStatusChecker, mInterval);
;
void startRepeatingTask()
mStatusChecker.run();
void stopRepeatingTask()
mHandler.removeCallbacks(mStatusChecker);
//added code start here
Runnable mAutoRefreshRunnable = new Runnable()
@Override
public void run()
fetchOrders()
mHandler.postDelayed(mAutoRefreshRunnable, 1000);
;
@Override
protected void onResume()
mHandler.postDelayed(mAutoRefreshRunnable, 1000);
@Override
protected void onPause()
mHandler.removeCallbacks(mAutoRefreshRunnable);
//added code ends here
/**
* This method is called when swipe refresh is pulled down
*/
@Override
public void onRefresh()
fetchOrders();
/**
* Fetching movies json by making http call
*/
private void fetchOrders()
// showing refresh animation before making http call
swipeRefreshLayout.setRefreshing(true);
// appending offset to url
String url = URL + offSet;
// Volley's json array request object
JsonArrayRequest req = new JsonArrayRequest(url,
new Response.Listener<JSONArray>()
@Override
public void onResponse(JSONArray response)
Log.d(TAG, response.toString());
if (response.length() > 0)
// looping through json and adding to order list
for (int i = 0; i < response.length(); i++)
try
JSONObject orderObj = response.getJSONObject(i);
int rank = orderObj.getInt("rank");
String title = orderObj.getString("title");
Order m = new Order(rank, title);
orderList.add(0, m);
// updating offset value to highest value
if (rank >= offSet)
offSet = rank;
catch (JSONException e)
Log.e(TAG, "JSON Parsing error: " + e.getMessage());
adapter.notifyDataSetChanged();
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
, new Response.ErrorListener()
@Override
public void onErrorResponse(VolleyError error)
Log.e(TAG, "Server Error: " + error.getMessage());
Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
);
// Adding request to request queue
MyApplication.getInstance().addToRequestQueue(req);
【讨论】：
嗨 Derek，感谢您的回复，我在 2 行上遇到编译错误：mAutoRefreshRunnable.fetchOrders(); .postDelayed(mAutoRefreshRunnable, 1000);可能是因为要求我导入 java.util.logging.Handler 或 android.Os.Handler 而我选择了 android.Os.Handler，介意我通过电子邮件将完整代码发送给您吗？ 嗯，我打错了，再检查更新的代码 另一个重要的问题，我如何在获取新数据后添加振动和声音响铃？ , 毕竟不是在每次自动刷新数据都插入之后 ***.com/questions/6462105/…，你可以看看这里。您可能需要创建一个单独的问题以获得最佳答案 将其作为一个新问题发布，并希望听到您的回答 - ***.com/questions/32537861/…以上是关于Android：在哪里以及如何自动刷新列表视图（我有刷新功能）的主要内容，如果未能解决你的问题，请参考以下文章