我一直在开发android应用程序.
我有后端(Web应用程序)和前端(Android应用程序).
在我的应用程序中,它的类别包含一堆项目列表.
当我选择一个类别时,它将调用一个用于调用DB中所有数据的任务.
任务完成后调用所有数据,它将直接指向活动.
活动将显示ListVIEw中的所有数据.
现在,例如,我从后端(Web)插入新数据.
我只想说我插入一个新的行包含一个拳击到运动类别.
因此,在DB中,它将在桌上运动中进行拳击.
在我的AndroID应用程序中,我目前处于运动类别.
因此,当拳击插入新数据库时,它应该有自动刷新并显示列表中的拳击.
但是,当我点击类别列表中的某个类别时,如果该任务仅运行一次,我该怎么办呢？
我想比较数据库中的数据总数和AndroID应用程序中显示的数据.
当数据不相同时,它将再次调用该任务.
这是我希望我的应用程序刷新的代码
ConnectivityManager connManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI); if(mWifi.isConnected()) { refresh = new Runnable() { public voID run() { // Do something handler.postDelayed(refresh, 1000); } }; handler.post(refresh); /*grIDArray = new ArrayList<FlipItem>(); adapter = new PackageListItemAdapter(this, this, grIDArray); adapter.notifyDataSetChanged();*/ } else { refresh = new Runnable() { public voID run() { // Do something handler.postDelayed(refresh, 60000); } }; handler.post(refresh); /*grIDArray = new ArrayList<FlipItem>(); adapter = new PackageListItemAdapter(this, this, grIDArray); adapter.notifyDataSetChanged();*/ }我在那里评论的代码,使我的列表只显示9我在DB上有15个项目.
这就是为什么我评论这条线
解决方法:
在适配器上调用notifyDataSetChanged().
有关如何/何时调用notifyDataSetChanged()的一些其他细节可以在此Google I/O video中查看.
使用Handler及其postDelayed方法使列表的适配器无效,如下所示：
final Handler handler = new Handler()handler.postDelayed( new Runnable() { @OverrIDe public voID run() { adapter.notifyDataSetChanged(); handler.postDelayed( this, 60 * 1000 ); }}, 60 * 1000 );您只能更新主(UI)线程中的UI.
通过在主线程中创建处理程序,您可以确保发布到处理程序的所有内容也在主线程中运行.
try { valIDat_user(receivedname); final Handler handler = new Handler(); handler.postDelayed( new Runnable() { @OverrIDe public voID run() { todoItems.clear(); //alertDialog.cancel(); valIDat_user(receivedname); handler.postDelayed( this, 60 * 1000 ); } }, 60 * 1000 ); } catch(Exception e) { display("Network error.\nPlease check with your network settings."); }首先验证用户是第一次加载数据,使用处理程序后我可以每隔一分钟更新一次值
我的完整代码如下
package com.example.employeeinduction;import java.io.BufferedReader;import java.io.IOException;import java.io.inputStream;import java.io.inputStreamReader;import java.util.ArrayList;import java.util.Collections;import java.util.Iterator;import java.util.List;import org.apache.http.httpResponse;import org.apache.http.nameValuePair;import org.apache.http.clIEnt.httpClIEnt;import org.apache.http.clIEnt.entity.UrlEncodedFormEntity;import org.apache.http.clIEnt.methods.httpPost;import org.apache.http.impl.clIEnt.DefaulthttpClIEnt;import org.apache.http.message.BasicnameValuePair;import org.apache.http.params.BasichttpParams;import org.apache.http.params.httpconnectionParams;import org.apache.http.params.httpParams;import org.Json.JsONArray;import org.Json.JsONObject;import androID.app.Activity;import androID.app.AlertDialog;import androID.app.ProgressDialog;import androID.content.Context;import androID.content.DialogInterface;import androID.content.Intent;import androID.content.res.TypedArray;import androID.os.AsyncTask;import androID.os.Bundle;import androID.os.Handler;import androID.support.v4.Widget.DrawerLayout;import androID.util.Log;import androID.vIEw.Menu;import androID.vIEw.MenuItem;import androID.vIEw.VIEw;import androID.Widget.AdapterVIEw;import androID.Widget.AdapterVIEw.OnItemClickListener;import androID.Widget.ArrayAdapter;import androID.Widget.ImageVIEw;import androID.Widget.ListVIEw;import androID.Widget.PopupMenu;import androID.Widget.PopupMenu.OnMenuItemClickListener;import androID.Widget.Toast;public class pdf extends Activity{ ImageVIEw iv; public boolean connect=false,logged=false; public String db_select; ListVIEw l1; AlertDialog alertDialog; String mPwd,Uname1="Success",Uname,ret,receivedname; public Iterator<String> itr; //private String SERVICE_URL = "http://61.12.7.197:8080/pdf"; //private String SERVICE_URL1 = "http://61.12.7.197:8080/url"; //private final String SERVICE_URL = "http://10.54.3.208:8080/Employee/person/pdf"; //private final String SERVICE_URL1 = "http://10.54.3.208:8080/Employee/person/url"; private final String SERVICE_URL = Urlmanager.Address+"pdf"; private final String SERVICE_URL1 = Urlmanager.Address+"url"; private final String TAG = "pdf"; ArrayList<String> todoItems; Boolean isInternetPresent = false; ConnectionDetector cd; ArrayAdapter<String> aa; public List<String> List1=new ArrayList<String>(); public DrawerLayout mDrawerLayout; public ListVIEw mDrawerList; //public ActionbarDrawerToggle mDrawerToggle; // NavigationDrawer Title "Nasdaq" in this example public CharSequence mDrawerTitle; // App Title "Navigation Drawer" in this example public CharSequence mTitle; // slIDer menu items details public String[] navMenuTitles=null; public TypedArray navMenuIcons; public ArrayList<NavDrawerItem> navDrawerItems; public NavDrawerlistadapter adapter; @OverrIDe protected voID onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentVIEw(R.layout.slIDing_project); iv = (ImageVIEw)findVIEwByID(R.ID.imageVIEw2); l1 = (ListVIEw)findVIEwByID(R.ID.List); mTitle = mDrawerTitle = getTitle(); // getting items of slIDer from array navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items); // getting Navigation drawer icons from res navMenuIcons = getResources() .obtainTypedArray(R.array.nav_drawer_icons); mDrawerLayout = (DrawerLayout) findVIEwByID(R.ID.drawer_layout); mDrawerList = (ListVIEw) findVIEwByID(R.ID.List_slIDermenu); navDrawerItems = new ArrayList<NavDrawerItem>(); // List item in slIDer at 1 Home Nasdaq details navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceID(0, -1))); // List item in slIDer at 2 Facebook details navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceID(1, -1))); // List item in slIDer at 3 Google details navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceID(2, -1))); // List item in slIDer at 4 Apple details // Recycle array navMenuIcons.recycle(); mDrawerList.setonItemClickListener(new SlIDeMenuClickListener()); // setting List adapter for Navigation Drawer adapter = new NavDrawerlistadapter(getApplicationContext(), navDrawerItems); mDrawerList.setAdapter(adapter); if (savedInstanceState == null) { displayVIEw(0); } iv.setonClickListener(new VIEw.OnClickListener() { @OverrIDe public voID onClick(VIEw v) { PopupMenu popup = new PopupMenu(getBaseContext(), v); /** Adding menu items to the popumenu */ popup.getMenuInflater().inflate(R.menu.main, popup.getMenu()); popup.setonMenuItemClickListener(new OnMenuItemClickListener() { @OverrIDe public boolean onMenuItemClick(MenuItem item) { switch (item.getItemID()){ case R.ID.Home: Intent a = new Intent(pdf.this,Design_Activity.class); startActivity(a); //Projects_Accel.this.finish(); // return true; break; case R.ID.logout: /*Intent z = new Intent(this,MainActivity.class); z.addFlags(Intent.FLAG_ACTIVITY_CLEAR_top); startActivity(z); this.finish();*/ Intent z = new Intent(pdf.this,MainActivity.class); z.setFlags(Intent.FLAG_ACTIVITY_CLEAR_top | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(z); pdf.this.finish(); // return true; break; } return true; } }); popup.show(); } }); todoItems = new ArrayList<String>(); aa = new ArrayAdapter<String>(this,R.layout.List_row,R.ID.Title,todoItems); l1.setAdapter(aa); todoItems.clear(); Intent intent = getIntent(); receivedname = (String) intent.getSerializableExtra("PROJECT"); cd = new ConnectionDetector(getApplicationContext()); isInternetPresent = cd.isConnectingToInternet(); if(isInternetPresent) { try { valIDat_user(receivedname); final Handler handler = new Handler(); handler.postDelayed( new Runnable() { @OverrIDe public voID run() { todoItems.clear(); //alertDialog.cancel(); valIDat_user(receivedname); handler.postDelayed( this, 60 * 1000 ); } }, 60 * 1000 ); } catch(Exception e) { display("Network error.\nPlease check with your network settings."); } } else { display("No Internet Connection.."); } l1.setonItemClickListener(new OnItemClickListener() { public voID onItemClick(AdapterVIEw<?> parent, VIEw vIEw, int position, long ID) { String name=(String)parent.getItemAtposition(position); /*Toast.makeText(getBaseContext(), name, Toast.LENGTH_LONG).show(); Intent i = new Intent(getBaseContext(),WebvIEw.class); i.putExtra("USERname", name); startActivity(i);*/ cd = new ConnectionDetector(getApplicationContext()); isInternetPresent = cd.isConnectingToInternet(); if(isInternetPresent) { try { valIDat_user1(receivedname,name); } catch(Exception e) { display("Network error.\nPlease check with your network settings."); } } else { display("No Internet Connection.."); } } }); } private class SlIDeMenuClickListener implements ListVIEw.OnItemClickListener {@OverrIDepublic voID onItemClick(AdapterVIEw<?> parent, VIEw vIEw, int position, long ID) { // display vIEw for selected item displayVIEw(position);}}@OverrIDepublic boolean onCreateOptionsMenu(Menu menu) {getMenuInflater().inflate(R.menu.main, menu);//setMenuBackground();return true;}/*@OverrIDepublic boolean onoptionsItemSelected(MenuItem item) {// Title/iconif (mDrawerToggle.onoptionsItemSelected(item)) { return true;}// Handle action bar actions clickswitch (item.getItemID()) {case R.ID.action_settings: return true;default: return super.onoptionsItemSelected(item);}}*///called when invalIDateOptionsMenu() invoke @OverrIDepublic boolean onPrepareOptionsMenu(Menu menu) {// if Navigation drawer is opened, hIDe the action items//boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);//menu.findItem(R.ID.action_settings).setVisible(!drawerOpen);return super.onPrepareOptionsMenu(menu);}private voID displayVIEw(int position) {// update the main content with called Fragmentswitch (position) {case 1: //fragment = new Fragment2Profile(); Intent i = new Intent(pdf.this,Design_Activity.class); startActivity(i); pdf.this.finish(); break;case 2: //fragment = new Fragment3logout(); Intent z = new Intent(pdf.this,MainActivity.class); z.setFlags(Intent.FLAG_ACTIVITY_CLEAR_top | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(z); pdf.this.finish(); break;default: break;}} public voID display(String msg) { Toast.makeText(pdf.this, msg, Toast.LENGTH_LONG).show(); } private voID valIDat_user(String st) { WebServiceTask wst = new WebServiceTask(WebServiceTask.POST_TASK, this, ""); wst.addnameValuePair1("table_name", st); // wst.addnameValuePair("Emp_PWD", stg2); // db_select=stg1; //display("I am"); wst.execute(new String[] { SERVICE_URL }); //display(SERVICE_URL); } private voID valIDat_user1(String stg1,String stg2) { db_select=stg1; WebServiceTask wst = new WebServiceTask(WebServiceTask.POST_TASK, this, "Loading..."); wst.addnameValuePair1("pdf_name", stg1); wst.addnameValuePair1("table_name1", stg2); wst.execute(new String[] { SERVICE_URL1 }); } @SuppressWarnings("deprecation") public voID no_net() { display( "No Network Connection"); final AlertDialog alertDialog = new AlertDialog.Builder(pdf.this).create(); alertDialog.setTitle("No Internet Connection"); alertDialog.setMessage("You don't have internet connection.\nElse please check the Internet Connection Settings."); //alertDialog.setIcon(R.drawable.error_info); alertDialog.setCancelable(false); alertDialog.setbutton("Close", new DialogInterface.OnClickListener() { public voID onClick(DialogInterface dialog, int which) { alertDialog.cancel(); pdf.this.finish(); System.exit(0); } }); alertDialog.setbutton2("Use Local DataBase", new DialogInterface.OnClickListener() { public voID onClick(DialogInterface dialog, int which) { display( "Accessing local DataBase....."); alertDialog.cancel(); } }); alertDialog.show(); } private class WebServiceTask extends AsyncTask<String, Integer, String> { public static final int POST_TASK = 1; private static final String TAG = "WebServiceTask"; // connection timeout, in milliseconds (waiting to connect) private static final int CONN_TIMEOUT = 12000; // socket timeout, in milliseconds (waiting for data) private static final int SOCKET_TIMEOUT = 12000; private int taskType = POST_TASK; private Context mContext = null; private String processMessage = "Processing..."; private ArrayList<nameValuePair> params = new ArrayList<nameValuePair>(); private ProgressDialog pDlg = null; public WebServiceTask(int taskType, Context mContext, String processMessage) { this.taskType = taskType; this.mContext = mContext; this.processMessage = processMessage; } public voID addnameValuePair1(String name, String value) { params.add(new BasicnameValuePair(name, value)); } @SuppressWarnings("deprecation") private voID showProgressDialog() { pDlg = new ProgressDialog(mContext); pDlg.setMessage(processMessage); pDlg.setProgressDrawable(mContext.getWallpaper()); pDlg.setProgressstyle(ProgressDialog.STYLE_SPINNER); pDlg.setCancelable(false); pDlg.show(); } @OverrIDe protected voID onPreExecute() { showProgressDialog(); } protected String doInBackground(String... urls) { String url = urls[0]; String result = ""; httpResponse response = doResponse(url); if (response == null) { return result; } else { try { result = inputStreamToString(response.getEntity().getContent()); } catch (IllegalStateException e) { Log.e(TAG, e.getLocalizedMessage(), e); } catch (IOException e) { Log.e(TAG, e.getLocalizedMessage(), e); } } return result; } @OverrIDe protected voID onPostExecute(String response) { handleResponse(response); pDlg.dismiss(); } // Establish connection and socket (data retrIEval) timeouts private httpParams gethttpParams() { httpParams htpp = new BasichttpParams(); httpconnectionParams.setConnectionTimeout(htpp, CONN_TIMEOUT); httpconnectionParams.setSoTimeout(htpp, SOCKET_TIMEOUT); return htpp; } private httpResponse doResponse(String url) { // Use our connection and data timeouts as parameters for our // DefaulthttpClIEnt httpClIEnt httpclIEnt = new DefaulthttpClIEnt(gethttpParams()); httpResponse response = null; try { switch (taskType) { case POST_TASK: httpPost httppost = new httpPost(url); // Add parameters httppost.setEntity(new UrlEncodedFormEntity(params)); response = httpclIEnt.execute(httppost); break; } } catch (Exception e) { display("Remote DataBase can not be connected.\nPlease check network connection."); Log.e(TAG, e.getLocalizedMessage(), e); return null; } return response; } private String inputStreamToString(inputStream is) { String line = ""; StringBuilder total = new StringBuilder(); // Wrap a BufferedReader around the inputStream BufferedReader rd = new BufferedReader(new inputStreamReader(is)); try { // Read response until the end while ((line = rd.readline()) != null) { total.append(line); } } catch (IOException e) { Log.e(TAG, e.getLocalizedMessage(), e); } // Return full string return total.toString(); } } public voID handleResponse(String response) { //display("JsON responce is : "+response); if(!response.equals("")) { try { JsONObject Jso = new JsONObject(response); int Uname = Jso.getInt("status1"); if(Uname==1) { String status = Jso.getString("reps1"); ret=status.substring(12,status.length()-2); todoItems.add(0, ret); aa.notifyDataSetChanged(); } else if(Uname==-1) { String status = Jso.getString("status"); //ret=status.substring(12,status.length()-2); //display(status); Intent intObj=new Intent(pdf.this,WebvIEw.class); intObj.putExtra("USERname",status); startActivity(intObj); } else if(Uname>1) {// int count=Integer.parseInt(Uname);// display("Number of Projects have been handling in AFL right Now: "+count); List1=new ArrayList<String>(); JsONArray array=Jso.getJsONArray("reps1"); for(int i=0;i<array.length();i++) { List1.add(array.getJsONObject(i).getString("pdfname")); }Collections.sort(List1); Collections.reverse(List1); itr=List1.iterator(); while(itr.hasNext()) { //str1=itr.next()+"\n"; todoItems.add(0, itr.next().toString()); aa.notifyDataSetChanged(); } //tv1.setText(str1); } else { final Context context = this; AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder( context); // set Title alertDialogBuilder.setTitle(""); // set dialog message alertDialogBuilder .setMessage("Records unavailable for this project!") .setCancelable(false) .setPositivebutton("Exit",new DialogInterface.OnClickListener() { public voID onClick(DialogInterface dialog,int ID) { // if this button is clicked, close // current activity pdf.this.finish(); } }); // create alert dialog alertDialog = alertDialogBuilder.create(); // show it alertDialog.show(); } } catch (Exception e) { Log.e(TAG, e.getLocalizedMessage(), e); return; } } else { display("unable to reach the server"); } } /** * SlIDer menu item click Listener * */ /*private class SlIDeMenuClickListener implements ListVIEw.OnItemClickListener { @OverrIDe public voID onItemClick(AdapterVIEw<?> parent, VIEw vIEw, int position, long ID) { // display vIEw for selected item displayVIEw(position); } } private voID displayVIEw(int position) { // update the main content with called Fragment // Fragment fragment = null; switch (position) { case 0: // fragment = new Fragment1User(); break; case 1: // fragment = new Fragment2Profile(); break; case 2: // fragment = new Fragment3logout(); break; default: break; } }*/}以上是内存溢出为你收集整理的新数据插入listview时Android自动刷新全部内容，希望文章能够帮你解决新数据插入listview时Android自动刷新所遇到的程序开发问题。
如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。
欢迎分享，转载请注明来源：内存溢出
微信扫一扫
支付宝扫一扫
评论列表（0条）