iOS UISearchBar with UITableView example

UISearchBar class provides a text field for entering text, a search button, a bookmark button, and a cancel button. With the help of the UISearchBarDelegate protocol you can implement the actions that will perform search on a database locally or send a request to the remote server when text is entered or buttons are clicked. In this example we implement the search bar to find a country by its name. The search request is sent to the remote server where a Java Servlet performs a simple query over the MySQL database to return a JSON array that is then displayed to the user using the Table view.

Java Servlet backend for remote search - CountrySearch.java

package com.as400samplecode;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

import com.as400samplecode.util.Country;
import com.google.gson.Gson;
import com.google.gson.JsonObject;

public class CountrySearch extends HttpServlet {
 
 private static final long serialVersionUID = 1L;
 
 public CountrySearch() {
  super();
 }

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  doPost(request,response);
 }

 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

  PrintWriter out = response.getWriter();
  
  //check of query data is sent
  String queryString = request.getParameter("queryString");
  if(queryString == null){
   queryString = "";
  }
  
  //get list of countries and prepare JSON array to send back
  ArrayList<Country> countryList = new ArrayList<Country>();
  Connection conn = null;             
  PreparedStatement stmt = null;      
  String sql = null;
  
  try {       
   Context ctx = (Context) new InitialContext().lookup("java:comp/env");
   conn = ((DataSource) ctx.lookup("jdbc/mysql")).getConnection(); 

   sql = "Select * from country where code <> 'CIV' "; 
   if(!queryString.trim().equals("")){
    sql += "and lcase(name) like ?";
   }
   
   stmt = conn.prepareStatement(sql);
   if(!queryString.trim().equals("")){
    stmt.setString(1, "%" + queryString.trim().toLowerCase() + "%" );
   }
   
   ResultSet rs = stmt.executeQuery();  
   while(rs.next()){ 
    
    Country country = new Country();
    country.setCode(rs.getString("code").trim());
    country.setName(rs.getString("name").trim());
    countryList.add(country);
    
   }                                                                          
   rs.close();                                                                
   
   stmt.close();                                                              
   stmt = null;                                                               
   conn.close();                                                              
   conn = null;  
   
  }                                                                
  catch(Exception e){
   e.printStackTrace();
  }                       

  finally {                                                        
   
   if (stmt != null) {                                             
    try {                                                          
     stmt.close();                                                 
    } catch (SQLException sqlex) {                                 
     // ignore -- as we can't do anything about it here            
    }                                                              

    stmt = null;                                             
   }                                                         

   if (conn != null) {                                       
    try {                                                    
     conn.close();                                           
    } catch (SQLException sqlex) {                           
     // ignore -- as we can't do anything about it here      
    }                                                        

    conn = null;                                             
   }                                                         
  } 
  
  Gson gson = new Gson();
  JsonObject myObj = new JsonObject();
  myObj.add("countryList", gson.toJsonTree(countryList));
  myObj.addProperty("success", true);
  out.println(myObj.toString());

 }
 
}

Interface file for the App Delegate - MySearchBarAppDelegate.h

#import <UIKit/UIKit.h>

@class MySearchBarViewController;

@interface MySearchBarAppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) MySearchBarViewController *viewController;

@end

Implementation file for the App Delegate - MySearchBarAppDelegate.m

#import "MySearchBarAppDelegate.h"
#import "MySearchBarViewController.h"

@implementation MySearchBarAppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[MySearchBarViewController alloc]
                           initWithNibName:@"MySearchBarViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

@end

Interface file for the UISearchBar View Controller - MySearchBarViewController.h

#import <UIKit/UIKit.h>

@interface MySearchBarViewController : UIViewController <UISearchBarDelegate,
                                UITableViewDelegate,UITableViewDataSource>

@property (nonatomic, strong) UISearchBar *mySearchBar;
@property (nonatomic, strong) UITableView *myTableView;
@property (nonatomic, strong) NSMutableArray *countryList;

@property (nonatomic, strong) NSString *queryString;

@end

Implementation file for the UISearchBar View Controller - MySearchBarViewController.m

#import "MySearchBarViewController.h"

@interface MySearchBarViewController ()

@end

@implementation MySearchBarViewController

@synthesize mySearchBar;
@synthesize myTableView;
@synthesize countryList;
@synthesize queryString;

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    //create a search bar and add to the top of the screen
 CGRect myFrame = CGRectMake(self.view.bounds.origin.x, self.view.bounds.origin.y,
                                self.view.bounds.size.width, 44.0f);
    self.mySearchBar = [[UISearchBar alloc] initWithFrame:myFrame];
    //set the delegate to self so we can listen for events
    self.mySearchBar.delegate = self;
    //display the cancel button next to the search bar
    self.mySearchBar.showsCancelButton = YES;
    //add the search bar to the view
    [self.view addSubview:self.mySearchBar];
    
    //set the frame for the table view
    myFrame.origin.y += 44;
    myFrame.size.height = self.view.bounds.size.height - 44;
    self.myTableView = [[UITableView alloc] initWithFrame:myFrame
                                                    style:UITableViewStylePlain];
    //set the table view delegate and the data source
    self.myTableView.delegate = self;
    self.myTableView.dataSource = self;
    //set table view resize attribute
    self.myTableView.autoresizingMask = UIViewAutoresizingFlexibleWidth |
                                        UIViewAutoresizingFlexibleHeight;
    //set background view and color
    self.myTableView.backgroundColor = [UIColor whiteColor];
    self.myTableView.backgroundView = nil;
    //add table view to the main view
    [self.view addSubview:self.myTableView];
    
    //execute the search without any query to display all countries
    [self handleSearch:self.mySearchBar];
}

//search button was tapped
- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar {
    [self handleSearch:searchBar];
}

//user finished editing the search text
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar {
    [self handleSearch:searchBar];
}

//do our search on the remote server using HTTP request
- (void)handleSearch:(UISearchBar *)searchBar {
    
    //check what was passed as the query String and get rid of the keyboard
    NSLog(@"User searched for %@", searchBar.text);
    self.queryString = searchBar.text;
    [searchBar resignFirstResponder];
    
    //setup the remote server URI
    NSString *hostServer = @"http://demo.mysamplecode.com/Servlets_JSP/";
    NSString *myUrlString = [NSString stringWithFormat:@"%@CountrySearch",hostServer];
    
    //pass the query String in the body of the HTTP post
    NSString *body;
    if(self.queryString){
        body =  [NSString stringWithFormat:@"queryString=%@", self.queryString];
    }
    NSURL *myUrl = [NSURL URLWithString:myUrlString];
    
    //make the HTTP request
    NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:myUrl];
    [urlRequest setTimeoutInterval:60.0f];
    [urlRequest setHTTPMethod:@"POST"];
    [urlRequest setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    [NSURLConnection
     sendAsynchronousRequest:urlRequest
     queue:queue
     completionHandler:^(NSURLResponse *response,
                         NSData *data,
                         NSError *error) {
         //we got something in reponse to our request lets go ahead and process this
         if ([data length] >0 && error == nil){
                 [self parseResponse:data];
         }
         else if ([data length] == 0 && error == nil){
             NSLog(@"Empty Response, not sure why?");
         }
         else if (error != nil){
             NSLog(@"Not again, what is the error = %@", error);
         }
     }];
    
}

//parse our JSON response from the server and load the NSMutableArray of countries
- (void) parseResponse:(NSData *) data {
    
    NSString *myData = [[NSString alloc] initWithData:data
                                             encoding:NSUTF8StringEncoding];
    NSLog(@"JSON data = %@", myData);
    NSError *error = nil;
    
    id jsonObject = [NSJSONSerialization
                     JSONObjectWithData:data
                     options:NSJSONReadingAllowFragments
                     error:&error];
    if (jsonObject != nil && error == nil){
        NSLog(@"Successfully deserialized...");
        
        NSNumber *success = [jsonObject objectForKey:@"success"];
        if([success boolValue] == YES){
            
            self.countryList = [jsonObject objectForKey:@"countryList"];
            dispatch_async(dispatch_get_main_queue(), ^{
                [self.myTableView reloadData];
            });
        }
        else {
            [self.navigationController popToRootViewControllerAnimated:YES];
        }
    }
    
}

//number of rows in a given section of a table view
- (NSInteger)tableView:(UITableView *)tableView
 numberOfRowsInSection:(NSInteger)section{
    
    NSInteger numberOfRows = 0;
    //get the count from the array
    if ([tableView isEqual:self.myTableView]){
        numberOfRows = self.countryList.count;
    }
    //if user searched for something and found nothing just add a row to display a message
    if(numberOfRows == 0 && [self.queryString length] > 0){
        numberOfRows = 1;
    }
    NSLog(@"Rows: %i", numberOfRows);
    return numberOfRows;
}


//asks the data source for a cell to insert in a particular location of the table view
- (UITableViewCell *) tableView:(UITableView *)tableView
          cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    
    UITableViewCell *myCellView = nil;
    
    if ([tableView isEqual:self.myTableView]){
        
        static NSString *TableViewCellIdentifier = @"CountryCells";
        //create a reusable table-view cell object located by its identifier
        myCellView = [tableView dequeueReusableCellWithIdentifier:TableViewCellIdentifier];
        if (myCellView == nil){
            myCellView = [[UITableViewCell alloc]
                          initWithStyle:UITableViewCellStyleValue1
                          reuseIdentifier:TableViewCellIdentifier];
        }
        
        //if there are countries to display
        if(self.countryList.count > 0){
            NSDictionary *countryInfo = [self.countryList objectAtIndex:indexPath.row];
            NSLog(@"Country Info = %@",countryInfo);
            
            NSString *countryCode = [countryInfo  valueForKey:@"code"];
            NSString *countryName = [countryInfo  valueForKey:@"name"];
            myCellView.textLabel.text = [NSString stringWithFormat:@"%@",countryName];
            myCellView.detailTextLabel.text = countryCode;
        }
        //display message to user
        else {
            myCellView.textLabel.text = @"No Results found, try again!";
            myCellView.detailTextLabel.text = @"";
        }
        
        //set the table view cell style
        [myCellView setSelectionStyle:UITableViewCellSelectionStyleNone];
        
    }
    return myCellView;
}

//user tapped on the cancel button
- (void)searchBarCancelButtonClicked:(UISearchBar *) searchBar {
    NSLog(@"User canceled search");
    [searchBar resignFirstResponder];
}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Reference

• iOS UISearchBar Class