我知道这是可能的,因为 Tapbots Pastebot 会这样做。当我的 iPhone 应用程序在后台运行时,我试图抓取 UIPasteboard 并将其添加到 UITableView 就像 Pastebot 一样,但我也在尝试缩短链接,如果它是一个 URL 并将其复制回 UIPastboard 以便它准备好供用户粘贴到任何地方。现在 Pastebot 显然通过播放音频文件 10 分钟在后台运行。我已经在 applicationDidFinishLaunching 中像这样设置了 NSNotificationCenter
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(pasteboardChangedNotification:) name:UIPasteboardChangedNotification object:[UIPasteboard generalPasteboard]];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(pasteboardChangedNotification:) name:UIPasteboardRemovedNotification object:[UIPasteboard generalPasteboard]];
- (void)pasteboardChangedNotification:(NSNotification*)notification {
pasteboardChangeCount_ = [UIPasteboard generalPasteboard].changeCount;
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
if (pasteboardChangeCount_ != [UIPasteboard generalPasteboard].changeCount) {
[[NSNotificationCenter defaultCenter] postNotificationName:UIPasteboardChangedNotification object:[UIPasteboard generalPasteboard]];
}
}
任何人都可以指出我如何抓取 UIPasteboard 并缩短链接,如果它是一个 URL 并将其发送回 UIPasteboard?我已经阅读了多任务开发文档和 UIPasteboard 文档。如果有人有解决方案,您可以与我分享吗?
谢谢
最佳答案
我设法实现类似目标的唯一方法是不打扰 NSNotificationCenter
,而只是在后台定期复制 UIPasteboard
的内容。
下面的代码每秒检查一次 UIPasteboard
一千秒。我相信一个应用程序可以在后台运行大约 10 分钟而不播放音频。如果您在后台播放音频文件,应用程序可以继续运行。
- (void)applicationDidEnterBackground:(UIApplication *)application
{
// Create a background task identifier
__block UIBackgroundTaskIdentifier task;
task = [application beginBackgroundTaskWithExpirationHandler:^{
NSLog(@"System terminated background task early");
[application endBackgroundTask:task];
}];
// If the system refuses to allow the task return
if (task == UIBackgroundTaskInvalid)
{
NSLog(@"System refuses to allow background task");
return;
}
// Do the task
dispatch_async(dispatch_get_global_queue(0, 0), ^{
NSString *pastboardContents = nil;
for (int i = 0; i < 1000; i++)
{
if (![pastboardContents isEqualToString:[UIPasteboard generalPasteboard].string])
{
pastboardContents = [UIPasteboard generalPasteboard].string;
NSLog(@"Pasteboard Contents: %@", pastboardContents);
}
// Wait some time before going to the beginning of the loop
[NSThread sleepForTimeInterval:1];
}
// End the task
[application endBackgroundTask:task];
});
}
关于iphone - 在后台运行时像 Pastebot 一样抓取 UIPasteboard,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/5721733/