没有互联网时如何从tableView中的plist读取数据

Question

我从 json url 在 plist 中写入数组。 我想当不存在互联网 tableview 时从 plist 获取数据，当存在时 tableView 从 json url 获取数据

这是我的代码（我在 Document 文件夹应用程序中创建 plist 文件）：

#import "ViewController.h"
#define DOC_DIR [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]


@implementation ViewController
{
    NSMutableArray *name;
    NSMutableData *data;
    NSString *listPath;
    NSMutableArray *array;
    NSArray *n;
    NSMutableArray *add;
}
@synthesize table;
-(NSString*)Dir
{
    return [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES)objectAtIndex:0];
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    NSURL *url = [NSURL URLWithString:@"http://myDomain.com/test.php"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    NSURLConnection *con = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    [con start];


}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    data = [[NSMutableData alloc]init];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData
{
    [data appendData:theData];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    name = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
    for (int i = 0; i < [name count]; i++) {

    NSIndexPath *indexPath = [self.table indexPathForSelectedRow];
    n = [[name objectAtIndex:(indexPath.row)+i]objectForKey:@"title"];
    if(!add){
        add = [NSMutableArray array];
    }
    [add addObject:n];
    }
    NSLog(@"add = %@",add);
    [table reloadData];
    [self WriteToPlist:add];
}
- (void)WriteToPlist:(NSArray*)dataArray
{
    NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:dataArray,@"Name", nil];
    NSString *Path = [DOC_DIR stringByAppendingPathComponent:@"Plist.plist"];
    [dic writeToFile:Path atomically:YES];
    NSLog(@"Path : %@",Path);
}

这段代码从 json 读取数据：

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return [name count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }
    cell.textLabel.text = [[name objectAtIndex:indexPath.row] objectForKey:@"title"];
//top code read data from json and I want when no internet read data from plist 
    return cell;
}

Answer 1

// Path to the plist (in the application bundle)
NSString *path = [[NSBundle mainBundle] pathForResource:
    @"Plist" ofType:@"plist"];

// Build the array from the plist  
NSMutableArray *array2 = [[NSMutableArray alloc] initWithContentsOfFile:path];

// Show the string values  
for (NSString *str in array2)
  NSLog(@"--%@", str);

你有数组，现在只需将值设置为数据源数组

[tableview reloadData];

要检查互联网连接，您可以使用Reachability class provided by apple

Answer 2

第1步：检查Internet是否已连接或未使用以下方法，实施此方法

- (BOOL) connectedToInternet
{
    NSURL *requestURL = [NSURL URLWithString:@"http://www.google.com"];
    NSData *data = [NSData dataWithContentsOfURL:requestURL];

    return ([data bytes]>0) ? YES : NO;
}

或

第 1 步：如果您知道的话，您还可以实现 Reachability Class 来检查 Apple 的 Internet 连接。

第 2 步：现在在调用 Web 服务请求之前检查您的方法中的连接性

if([self connectedToInternet])
{
    // Make a reqeust to server
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    NSURL *url = [NSURL URLWithString:@"http://yourDomain.com/test.php"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    NSURLConnection *con = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    [con start];
}
else
{
    // Write a Handy code to load Data from Your Local Plist
    // Path to plist From Documents Folder
    NSString *docFilePath = [DOC_DIR stringByAppendingPathComponent:@"Data.plist"];

    NSDictionary *dictData = [NSDictionary dictionaryWithContentsOfFile:docFilePath];


    NSLog(@"%@",dictData);
    // Reload your TableView
}