我知道这是可能的,因为 Tapbots Pastebot 就是这么做的。我试图在我的 iPhone 应用程序在后台运行时抓取 UIPasteboard 并将其添加到 UITableView 中,就像 Pastebot 所做的那样,但我也尝试缩短链接(如果它是 URL)并将其复制回 UIPastboard 以便准备就绪供用户粘贴到任何地方。现在,Pastebot 显然在后台运行,播放音频文件 10 分钟。我已经在 applicationDidFinishLaunching 中设置了 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]];
}
}
任何人都可以为我指明获取 UIPasteboard 并缩短链接(如果它是 URL)并将其发送回 UIPasteboard 的方向吗?我已阅读多任务开发文档和 UIPasteboard 文档。如果有人有解决方案,可以与我分享吗?
Thanks
我成功实现类似目标的唯一方法就是不去理会NSNotificationCenter
而只是复制内容UIPasteboard
在后台定期进行。
下面的代码检查UIPasteboard
每秒一次,持续一千秒。我相信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];
});
}
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