iOS 開發筆記 - 呼叫外部程式來處理一些資源（URL Scheme）

把一些 resource 轉交給外部程式，常見的就是 URL Scheme 技巧。

已知 URL scheme ，判斷是否支援：

if ([[UIApplication sharedApplication] canOpenURL:url])
    [[UIApplication sharedApplication] openURL:url];

若是 file:// 開頭的，可以用這試試：

UIDocumentInteractionController *dic = [UIDocumentInteractionController interactionControllerWithURL:url];
[dic presentOptionsMenuFromRect:self.view.bounds inView:self.view animated:YES];

其他，可以用這試試：

UIActivityViewController *avc = [[UIActivityViewController alloc] initWithActivityItems:@[url] applicationActivities:nil];
[self presentViewController:avc animated:YES completion:nil];

iOS 開發筆記 - 使用 Facebook SDK 4.0 分享至塗鴉牆與簡易的 publish_actions 權限判斷流程

大概都遵循 Facebook 文件，這邊指紀錄在一個 ViewController 中，啟動分享至使用者塗鴉牆的流程，包括判斷使用者是否安裝過 Facebook app、是否授權 publish_actions 等，以及選擇用 Facebook app 分享或是用 Facebook SDK 分享等。

#import <FBSDKCoreKit/FBSDKCoreKit.h>
#import <FBSDKShareKit/FBSDKShareLinkContent.h>
#import <FBSDKShareKit/FBSDKShareDialog.h>
#import <FBSDKShareKit/FBSDKShareAPI.h>
#import <FBSDKShareKit/FBSDKShareOpenGraphAction.h>

#import <FBSDKLoginKit/FBSDKLoginManager.h>
#import <FBSDKLoginKit/FBSDKLoginManagerLoginResult.h>

@interface ViewController () <FBSDKSharingDelegate>
@property (nonatomic, strong) NSString *url;
@end

@implementation ViewController

#pragma mark - FBSDKSharingDelegate

- (void)sharer:(id<FBSDKSharing>)sharer didCompleteWithResults:(NSDictionary *)results {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"INFO" message:@"done" delegate:nil cancelButtonTitle:@"ok" otherButtonTitles: nil];
    [alertView show];
}

- (void)sharer:(id<FBSDKSharing>)sharer didFailWithError:(NSError *)error {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"INFO" message:@"error" delegate:nil cancelButtonTitle:@"ok" otherButtonTitles: nil];
    [alertView show];
}

- (void)sharerDidCancel:(id<FBSDKSharing>)sharer {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"INFO" message:@"cancel" delegate:nil cancelButtonTitle:@"ok" otherButtonTitles: nil];
    [alertView show];
}

#pragma mark - share methods

- (void)useFacebookApp {
    FBSDKShareLinkContent *content = [[FBSDKShareLinkContent alloc] init];
    content.contentURL = [NSURL URLWithString:self.url];
    [FBSDKShareDialog showFromViewController:self
                                 withContent:content
                                    delegate:nil];
}

- (void)useFacebookSDK {
    FBSDKShareLinkContent *content = [[FBSDKShareLinkContent alloc] init];
    content.contentURL = [NSURL URLWithString:self.url];
    [FBSDKShareAPI shareWithContent:content delegate:self];
}

#pragma mark - init action

- (void)doShare
{
    if (![FBSDKAccessToken currentAccessToken]) {
        FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];
        [login logInWithPublishPermissions:@[@"publish_actions"] handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
            if (error) {
                // Process error
                NSLog(@"Process error");
            } else if (result.isCancelled) {
                // Handle cancellations
            } else {
                if ([result.grantedPermissions containsObject:@"publish_actions"]) {
                    [self useFacebookSDK];
                } else {
                    [self useFacebookApp];
                }
            }
        }];
        return;
    } else if ([[FBSDKAccessToken currentAccessToken] hasGranted:@"publish_actions"]) {
        [self useFacebookSDK];
    } else {
        [self useFacebookApp];
    }
    return;
}

@end