Question

如何创建一个应用程序，在SQLite数据库中记录一系列经度和纬度值，并将它们显示为MapActivity上的彩色轨迹。

我需要帮助。如何将地图坐标存储在sqlite数据库中，并在表格中显示旅程详细信息。例如，我已经完成了从孟买到浦那的一次旅程。然后如何将数据存储到数据库中，以供将来参考。当用户点击旅程名称时它应该提供所有细节

Answer 1

如果您是Sqlite的新手，那么请查看此类以获取数据库创建两个数据库文件，如下所示

----＆GT;＆GT;＆GT;＆GT; Database.h

在此文件中写下以下代码

#import <Foundation/Foundation.h>
#import <sqlite3.h>


@interface DataBase : NSObject {

    sqlite3 *database;

}

+(DataBase *) shareDataBase;

-(BOOL) createDataBase:(NSString *)DataBaseName;

-(NSString*) GetDatabasePath:(NSString *)database;

-(NSMutableArray *) getAllDataForQuery:(NSString *)sql  forDatabase:(NSString *)database;
-(void) inseryQuery:(NSString *) insertSql forDatabase:(NSString *)database1;
-(void) deleteQuery:(NSString *) deleteSql forDatabase:(NSString *)database1;
-(void) updateQuery:(NSString *) updateSql forDatabase:(NSString *)database1;

@end

----＆GT;＆GT;＆GT;＆GT; Database.m

在此文件中写下以下代码

#import "DataBase.h"


@implementation DataBase

static DataBase *SampleDataBase =nil;


+(DataBase*) shareDataBase{

    if(!SampleDataBase){
        SampleDataBase = [[DataBase alloc] init];
    }

    return SampleDataBase;

}


-(NSString *) GetDatabasePath:(NSString *)database1{


    [self createDataBase:database1];

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    return [documentsDirectory stringByAppendingPathComponent:database1];
}


-(BOOL) createDataBase:(NSString *)DataBaseName{
    BOOL success; 

    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:DataBaseName];

    success = [fileManager fileExistsAtPath:writableDBPath];
    if (success) return success;
    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:DataBaseName];
    success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];

    if (!success) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error!!!" message:@"Failed to create writable database" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil];
        [alert show];
        [alert release];

    }
    return success;
}



-(NSMutableArray *) getAllDataForQuery:(NSString *)sql  forDatabase:(NSString *)database1{

    sqlite3_stmt *statement = nil ;

    NSString *path = [self GetDatabasePath:database1];

    NSMutableArray *alldata;
    alldata = [[NSMutableArray alloc] init];

    if(sqlite3_open([path UTF8String],&database) == SQLITE_OK )
    {
        NSString *query = sql;

        if((sqlite3_prepare_v2(database,[query UTF8String],-1, &statement, NULL)) == SQLITE_OK)
        {
            while(sqlite3_step(statement) == SQLITE_ROW)
            {   

                NSMutableDictionary *currentRow = [[NSMutableDictionary alloc] init];

                int count = sqlite3_column_count(statement);

                for (int i=0; i < count; i++) {

                    char *name = (char*) sqlite3_column_name(statement, i);
                    char *data = (char*) sqlite3_column_text(statement, i);

                    NSString *columnData;
                    NSString *columnName = [NSString stringWithCString:name encoding:NSUTF8StringEncoding];


                    if(data != nil)
                        columnData = [NSString stringWithCString:data encoding:NSUTF8StringEncoding];
                    else {
                        columnData = @"";
                    }

                    [currentRow setObject:columnData forKey:columnName];
                }

                [alldata addObject:currentRow];
            }
        }
        sqlite3_finalize(statement); 
    }
    sqlite3_close(database);

    return alldata;

}

-(void) inseryQuery:(NSString *) insertSql forDatabase:(NSString *)database1{

    sqlite3_stmt *statement = nil ;

    NSString *path = [self GetDatabasePath:database1];

    if(sqlite3_open([path UTF8String],&database) == SQLITE_OK )
    {
        if((sqlite3_prepare_v2(database,[insertSql UTF8String],-1, &statement, NULL)) == SQLITE_OK)
        {
            if(sqlite3_step(statement) == SQLITE_OK){
            }
        }
        sqlite3_finalize(statement); 
    }
    sqlite3_close(database);

}

-(void) updateQuery:(NSString *) updateSql forDatabase:(NSString *)database1{

    sqlite3_stmt *statement = nil ;

    NSString *path = [self GetDatabasePath:database1];

    if(sqlite3_open([path UTF8String],&database) == SQLITE_OK )
    {
        if((sqlite3_prepare_v2(database,[updateSql UTF8String],-1, &statement, NULL)) == SQLITE_OK)
        {
            if(sqlite3_step(statement) == SQLITE_OK){
            }
        }
        sqlite3_finalize(statement); 
    }
    sqlite3_close(database);

}

-(void) deleteQuery:(NSString *) deleteSql forDatabase:(NSString *)database1{

    sqlite3_stmt *statement = nil ;

    NSString *path = [self GetDatabasePath:database1];

    if(sqlite3_open([path UTF8String],&database) == SQLITE_OK )
    {
        if((sqlite3_prepare_v2(database,[deleteSql UTF8String],-1, &statement, NULL)) == SQLITE_OK)
        {
            if(sqlite3_step(statement) == SQLITE_OK){
            }
        }
        sqlite3_finalize(statement); 
    }
    sqlite3_close(database);

}



@end

现在获取数据使用以下代码

NSString *sql = @"select * from UserInfo"; <br>
userInfo = [[DataBase shareDataBase] getAllDataForQuery:sql forDatabase:@"Sample.db"];

它将以NSDictionary的形式返回所有行的数组。

要添加新记录，请使用以下代码

NSString *sql = [NSString stringWithFormat:@"insert into userInfo values ('city','name','phone')"];
[[DataBase shareDataBase] inseryQuery:sql forDatabase:@"Sample.db"];

同样，还有更新和删除记录的方法。

所以这是我见过的最好的例子，我们只需要调用一个方法来获取，插入，更新或删除。

感谢您看到这个问题，

Answer 2

在项目中获取位置导入管理框架。点击此链接

http://developer.apple.com/library/ios/#samplecode/LocateMe/Introduction/Intro.html#//apple_ref/doc/uid/DTS40007801获取获取位置的示例。

这是在json中设置位置的格式

[{ “经度”： “45.2655”， “纬度”： “23.2655”}，{ “经度”： “45.2655”， “纬度”： “23.2655”}，{ “经度”： “45.2655”，”纬度 “：” 23.2655" }]

感谢。

Answer 3

您需要创建一个包含字段的表...... Source，Destination，SourceLat，SourceLong，DestinationLat，DestinationLong .......在此您将传递

Source - Mumbai,(or other) - text - varchar type
Destinatino - Pune, (or other) -text - varchar type
SourceLat - coordinate.latitude; - number with decimal precison upto 10 points.
SourceLong - coordinate.longitude - number with decimal precison upto 10 points.
DestinationLat - coordinate.latitude; - number with decimal precison upto 10 points.
DestinationLong - coordinate.longitude - number with decimal precison upto 10 points.

谢谢，

Answer 4

首先你需要创建NSMutableArray * arrayOflocation的对象;在.h文件中，

然后在您的locationUpdate方法中编写以下代码

NSMutableDictionary *LocationDic = [[NSMutableDictionary alloc] init];
[LocationDic setObject:[NSString stringWithFormat:@"%f",c.latitude] forKey:@"Latitude"];
[LocationDic setObject:[NSString stringWithFormat:@"%f",c.longitude] forKey:@"Longitude"];

[arrayOflocation addObject:LocationDic];

现在当您保存行程时，您需要为json格式创建字符串，因为您需要使用json API，您可以轻松地使用google获取它。如果要将字符串保存在文件中，请编写以下代码。

NSString *dataString = [arrayOflocation JSONRepresentation];
//// code to write dataString in txt file.

并且最终需要将文件名存储在sqlite中以及旅行的其他细节。

使地图坐标（lan，＆amp; long）存储在sqlite数据库中

4 个答案: