IOS learning 4. Storing chat records and ios storing chat records

IOS learning 4. Storing chat records and ios storing chat records

It mainly uses sqlite3 to store chat records

Import sqlite3.dylib, click Add Other, and press shift + command + G to enter/Usr/lib/libsqlite3.dylibAnd then OK. Import <sqlite3.h>

1. A new file Text class is used for storage, and. m does not require any operation.

1 # import <Foundation/Foundation. h> 2 3 @ interface Text: NSObject4 // chat content 5 @ property (nonatomic, copy) NSString * userText; 6 // The time when the chat content is sent 7 @ property (nonatomic, copy) NSString * currentTime; 8 @ end

2. encapsulate another TextModel class for Data Operations

1 # import <Foundation/Foundation. h> 2 # import <sqlite3.h> 3 @ class Text; 4 @ interface TextModel: NSObject 5 // create table 6-(BOOL) createList :( sqlite3 *) db; 7 // insert 8-(BOOL) insertList :( Text *) insertList; 9 // get data 10-(NSMutableArray *) getList; 11 @ end

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/// TextModel. m // Save the chat record /// Created by 736376103@qq.com on 16/4/4. // Copyright©2016 736376103@qq.com. all rights reserved. // # import "TextModel. h "# import" Text. h "@ implementation TextModel // defines a variable static sqlite3 * _ database;-(NSString *) filename {NSString * path = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) lastObject]; // print it here. It is convenient to use MesaSQLite to open the sqlite3 file, which can be added, deleted, modified, and queried. It is mainly free of charge ~~~ NSLog (@ "% @", path); return [path stringByAppendingPathComponent: @ "LIKE. sqlite "];}-(BOOL) openDB {// obtain path NSString * path = [self filename]; NSFileManager * fileManager = [NSFileManager defaultManager]; // determine whether the database has BOOL find = [fileManager fileExistsAtPath: path]; // if it is true, open the database. if it does not exist, if (find) is automatically created) {NSLog (@ "database exists"); if (sqlite3_open ([path UTF8String], & _ database )! = SQLITE_ OK) {// failed disabled. It is said that this is a good habit. It is hard to understand sqlite3_close (_ database); NSLog (@ "failed to open the database"); return NO ;} // create a table [self createList: _ database]; return YES;} // same as if (sqlite3_open (path. UTF8String, & _ database) = SQLITE_ OK) {[self createList: _ database]; return YES;} else {sqlite3_close (_ database ); NSLog (@ "failed to open database"); return NO;} # pragma mark -- Create Table-(BOOL) createList :( sqlite3 *) db {// I am missing a primary key Add it by yourself. -- id integer primary key autoincrement NSString * SQL = [NSString stringWithFormat: @ "CREATE TABLE IF NOT EXISTS DRINK (userText TEXT, currentTime TEXT)"]; sqlite3_stmt * stmt; // The sqlite3_prepare_v2 interface resolves an SQL statement to the statement structure. using this interface to access the database is currently a better method NSInteger sqlReturn = sqlite3_prepare_v2 (_ database, SQL. UTF8String,-1, & stmt, NULL); //-1 indicates the length of the SQL statement. <0 automatically calculates if (sqlReturn! = SQLITE_ OK) {NSLog (@ "failed to create table"); return NO;} int success = sqlite3_step (stmt); // release stmt sqlite3_finalize (stmt); if (success! = SQLITE_DONE) {NSLog (@ "Table creation failed"); return NO;} NSLog (@ "table created successfully"); return YES ;} # pragma mark -- insert-(BOOL) insertList :( Text *) insertList {if ([self openDB]) {sqlite3_stmt * stmt ;//? NSString * SQL = [NSString stringWithFormat: @ "INSERT INTO DRINK (userText, currentTime) VALUES (?,?) "]; // Int success = sqlite3_exec (_ database, SQL. UTF8String, NULL, NULL, & error); int success = sqlite3_prepare_v2 (_ database, SQL. UTF8String,-1, & stmt, NULL); if (success! = SQLITE_ OK) {NSLog (@ "insert failed"); sqlite3_close (_ database); return NO;} sqlite3_bind_text (stmt, 1, [insertList. userText UTF8String],-1, SQLITE_TRANSIENT); sqlite3_bind_text (stmt, 2, [insertList. currentTime UTF8String],-1, SQLITE_TRANSIENT); // execute the insert statement success = sqlite3_step (stmt); // release stmt sqlite3_finalize (stmt); NSLog (@ "% @", insertList. userText); NSLog (@ "% @", insertList. currentTime); // If fail Ed if (success = SQLITE_ERROR) {NSLog (@ "failed insert into database"); sqlite3_close (_ database); return NO;} sqlite3_close (_ database); return YES ;} return NO; }# pragma mark -- Get-(NSMutableArray *) getList {NSMutableArray * array = nil; // you can check whether the function is enabled, here we can use dispatch_once to execute only once if ([self openDB]) {sqlite3_stmt * stmt; NSString * SQL = [NSString stringWithFormat: @ "SELECT userText, currentTime FROM DRINK"]; If (sqlite3_prepare_v2 (_ database, SQL. UTF8String,-1, & stmt, NULL )! = SQLITE_ OK) {NSLog (@ "failed to get list");} else {array = [NSMutableArray array]; // traverses records, starting from 0, do not write the error while (sqlite3_step (stmt) = SQLITE_ROW) {Text * p = [[Text alloc] init]; char * strText = (char *) sqlite3_column_text (stmt, 0); // make a judgment. if the record is nil and it is not executed, let's think about it here, why should we judge if (strText! = NULL) {p. userText = [NSString stringwithuf8string: strText];} char * strTime = (char *) sqlite3_column_text (stmt, 1); // if (strTime! = NULL) {p. currentTime = [NSString stringwithuf8string: strTime] ;}// Add a variable array [array addObject: p] ;}// release stmt sqlite3_finalize (stmt); sqlite3_close (_ database );} return array;} @ end

3. ViewController. h: drag a tableview and a textfield on the storyboard.

#import <UIKit/UIKit.h>@interface ViewController : UIViewController@property (weak, nonatomic) IBOutlet UITableView *tableview;@property (weak, nonatomic) IBOutlet UITextField *textField;@end

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/// ViewController. m // Save the chat record /// Created by 736376103@qq.com on 16/4/4. // Copyright©2016 736376103@qq.com. all rights reserved. // # import "ViewController. h "# import" TableViewCell. h "# import" Text. h "# import" TextModel. h "// implement UITablevView and UITextField proxy @ interface ViewController () <UITableViewDataSource, UITableViewDelegate, UITextFieldDelegate> // data source @ property (nonatomic, strong) NSMutableArray * dataSource; // data processing class @ property (nonatomic, strong) TextModel * textModel; @ end @ implementation ViewController // load data-(void) reloadDataSource {if (_ textModel = nil) {_ textModel = [[TextModel alloc] init];} // get data _ dataSource = [_ textModel getList];}-(void) viewDidLoad {[super viewDidLoad]; // sets proxy _ textField. delegate = self; // call the data loading method [self reloadDataSource];}-(void) didreceivemorywarning {[super didreceivemorywarning];}-(void) sendMessageContent :( NSString *) text {// obtain the time NSDate * date = [NSDate date]; NSDateFormatter * dateForMatter = [[NSDateFormatter alloc] init]; // hh: mm is in the format, datformatter can be used freely. dateFormat = @ "hh: mm"; NSString * timeString = [dateForMatter stringFromDate: date]; Text * t = [[Text alloc] init]; // The property t that saves the time to Text. currentTime = timeString; // input content t. userText = text; // insert it to the database [_ textModel insertList: t];} # pragma mark -- UITextField proxy-(BOOL) textFieldShouldReturn :( UITextField *) textField {// custom method to save the input content to Text [self sendMessageContent: textField. text]; // cancel the first response [textField resignFirstResponder]; // clear the keyboard textField. text = @ ""; // after the data is inserted, load the data once, equivalent to adding data to the data source [self reloadDataSource]; // refresh the interface, display the newly inserted data [_ tableview reloadData]; return YES ;}# pragma mark -- TableView Data Source-(NSInteger) tableView :( UITableView *) tableView numberOfRowsInSection :( NSInteger) section {return _ dataSource. count;}-(UITableViewCell *) tableView :( UITableView *) tableView cellForRowAtIndexPath :( NSIndexPath *) indexPath {Text * p = _ dataSource [indexPath. row]; // custom Cell TableViewCell * cell = [TableViewCell tableView: tableView]; // cell cannot be clicked. selectionStyle = UITableViewCellSelectionStyleNone; cell. timeLabel. text = p. currentTime; cell. otherLabel. text = p. userText; return cell ;}# pragma mark -- proxy method-(CGFloat) tableView :( UITableView *) tableView heightForRowAtIndexPath :( NSIndexPath *) indexPath {return 80 ;}@ end

4. Custom cell

# Import <UIKit/UIKit. h> @ interface TableViewCell: UITableViewCell // chat content @ property (strong, nonatomic) UILabel * OtherLabel; // time @ property (strong, nonatomic) UILabel * timeLabel; // avatar, find a graph by yourself @ property (strong, nonatomic) UIImageView * meImageView; + (instancetype) tableView :( UITableView *) tableView; @ end

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/// TableViewCell. m // Save the chat record /// Created by 736376103@qq.com on 16/4/4. // Copyright©2016 736376103@qq.com. all rights reserved. // # import "TableViewCell. h "@ implementation TableViewCell // create the control-(id) initWithStyle :( identifier) style reuseIdentifier :( NSString *) reuseIdentifier {if (self = [super initWithStyle: style reuseIdentifier: reuseIdentifier]) {CGFloat width = [UIScreen mainScreen]. bounds. size. width; _ OtherLabel = [[UILabel alloc] initWithFrame: CGRectMake (0, 40, width-40, 30)]; _ OtherLabel. font = [UIFont systemFontOfSize: 16]; _ OtherLabel. numberOfLines = 0; _ OtherLabel. lineBreakMode = NSLineBreakByTruncatingTail; _ OtherLabel. textAlignment = NSTextAlignmentRight; [self. contentView addSubview: _ OtherLabel]; _ timeLabel = [[UILabel alloc] initWithFrame: CGRectMake (width/2-20, 0, 40, 20)]; _ timeLabel. font = [UIFont systemFontOfSize: 12]; [self. contentView addSubview: _ timeLabel]; _ meImageView = [[UIImageView alloc] initWithFrame: CGRectMake (width-40, 10, 30, 30)]; _ meImageView. image = [UIImage imageNamed: @ "003"]; [self. contentView addSubview: _ meImageView];} return self;} + (instancetype) tableView :( UITableView *) tableView {TableViewCell * cell = [tableView dequeueReusableCellWithIdentifier: @ "ChatTableViewCell"] // cell reuse if (cell = nil) {cell = [[TableViewCell alloc] initWithStyle: UITableViewCellStyleDefault reuseIdentifier: @ "ChatTableViewCell"];} return cell;} @ end