iOS GCD多執行緒

多執行緒 iOS開發 · 發表 2018-12-04 18:43:20

摘要：直接上程式碼 --> 各種執行緒的建立方式 /// 建立非同步佇列 dispatch_queue_t async = dispatch_queue_create("async_queue", DISPATCH_QUEUE_CON...

直接上程式碼 --> 各種執行緒的建立方式

/// 建立非同步佇列
dispatch_queue_t async = dispatch_queue_create("async_queue", DISPATCH_QUEUE_CONCURRENT);
/// 建立同步佇列
dispatch_queue_t sync = dispatch_queue_create("sync_queue", DISPATCH_QUEUE_SERIAL);


/// 建立主佇列
dispatch_queue_t main_queue = dispatch_get_main_queue();

/// 全域性併發佇列
dispatch_queue_t global_queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

/// 同步
dispatch_sync(global_queue, ^{

});

/// 非同步
dispatch_async(global_queue, ^{

});

執行緒建立的6中方式

第一種 --> 同步併發(從上往下依次執行，沒有開啟新執行緒) 在當前執行緒中執行任務，不會開啟新執行緒，執行完一個任務，再執行下一個任務
| 執行結果 --> 新增至主執行緒執行先執行begin最後執行end，依次執行

- (void)syncConcurrentThread
{
NSLog(@"同步併發---begin %@",[NSThread currentThread]);
dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_CONCURRENT);
dispatch_sync(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncConcurrent = 1--%@",[NSThread currentThread]);
}
});
dispatch_sync(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncConcurrent = 2--%@",[NSThread currentThread]);
}
});
dispatch_sync(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncConcurrent = 3--%@",[NSThread currentThread]);
}
});
NSLog(@"同步併發---end %@",[NSThread currentThread]);

}
執行結果：
同步併發---begin <NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 1--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 1--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 1--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 2--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 2--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 2--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 3--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 3--<NSThread: 0x600000566940>{number = 1, name = main}
syncConcurrent = 3--<NSThread: 0x600000566940>{number = 1, name = main}
同步併發---end <NSThread: 0x600000566940>{number = 1, name = main}

第二種 --> 非同步併發(開啟多個新執行緒，任務隨機接近同時執行) 可以開啟多個執行緒，任務同時隨機執行
| 執行結果 --> 先執行主執行緒程式碼(begin，end)，在執行子執行緒程式碼，並隨機執行

- (void)asyncConcurrentThread
{
NSLog(@"非同步併發---begin %@",[NSThread currentThread]);

dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_CONCURRENT);
dispatch_async(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncConcurrent = 1--%@",[NSThread currentThread]);
}
});
dispatch_async(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncConcurrent = 2--%@",[NSThread currentThread]);
}
});
dispatch_async(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncConcurrent = 3--%@",[NSThread currentThread]);
}
});
NSLog(@"非同步併發---end %@",[NSThread currentThread]);

}
執行結果：
非同步併發---begin <NSThread: 0x600000566940>{number = 1, name = main}
非同步併發---end <NSThread: 0x600000566940>{number = 1, name = main}
asyncConcurrent = 1--<NSThread: 0x600000538980>{number = 3, name = (null)}
asyncConcurrent = 3--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncConcurrent = 2--<NSThread: 0x60000050ad40>{number = 5, name = (null)}
asyncConcurrent = 1--<NSThread: 0x600000538980>{number = 3, name = (null)}
asyncConcurrent = 3--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncConcurrent = 2--<NSThread: 0x60000050ad40>{number = 5, name = (null)}
asyncConcurrent = 1--<NSThread: 0x600000538980>{number = 3, name = (null)}
asyncConcurrent = 3--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncConcurrent = 2--<NSThread: 0x60000050ad40>{number = 5, name = (null)}

第三種 --> 同步序列 (任務依次執行，沒有開啟新執行緒) 不會開啟新執行緒，在當前執行緒執行任務。任務是序列的，執行完一個任務，再執行下一個任務
| 執行結果 --> 先執行主執行緒的程式碼(begin,end)，在加入主執行緒依次執行

- (void)syncSerialThread
{
NSLog(@"同步序列---begin %@",[NSThread currentThread]);

dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_SERIAL);
dispatch_sync(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncSerial = 1--%@",[NSThread currentThread]);
}
});
dispatch_sync(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncSerial = 2--%@",[NSThread currentThread]);
}
});
dispatch_sync(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncSerial = 3--%@",[NSThread currentThread]);
}
});
NSLog(@"同步序列---end %@",[NSThread currentThread]);

}
執行結果：
同步序列---begin <NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 1--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 1--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 1--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 2--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 2--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 2--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 3--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 3--<NSThread: 0x600000566940>{number = 1, name = main}
syncSerial = 3--<NSThread: 0x600000566940>{number = 1, name = main}
同步序列---end <NSThread: 0x600000566940>{number = 1, name = main}

第四種 --> 非同步序列 (開啟一個執行緒) 會開啟新執行緒，但是因為任務是序列的，執行完一個任務，再執行下一個任務
| 執行結果 --> 先執行主執行緒(begin,end)，然後在新的執行緒依次執行任務

- (void)asyncSerialThread
{
NSLog(@"非同步序列---begin %@",[NSThread currentThread]);

dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_SERIAL);
dispatch_async(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncSerial = 1--%@",[NSThread currentThread]);
}
});
dispatch_async(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncSerial = 2--%@",[NSThread currentThread]);
}
});
dispatch_async(sync, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncSerial = 3--%@",[NSThread currentThread]);
}
});
NSLog(@"非同步序列---end %@",[NSThread currentThread]);

}
執行結果：
非同步序列---begin <NSThread: 0x600000566940>{number = 1, name = main}
非同步序列---end <NSThread: 0x600000566940>{number = 1, name = main}
asyncSerial = 1--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 1--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 1--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 2--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 2--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 2--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 3--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 3--<NSThread: 0x600000538880>{number = 4, name = (null)}
asyncSerial = 3--<NSThread: 0x600000538880>{number = 4, name = (null)}

第五種 --> 同步執行 + 主佇列在主執行緒呼叫(卡死) 在其他執行緒呼叫(不會卡死，不會開啟新執行緒，依次執行)
| 執行結果 --> 在主佇列執行(卡死) 在子執行緒中(依次執行)

- (void)syncMainThread
{
NSLog(@"同步執行 + 主佇列 ---begin %@",[NSThread currentThread]);

dispatch_queue_t main_queue = dispatch_get_main_queue();
dispatch_sync(main_queue, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncMain = 1--%@",[NSThread currentThread]);
}
});
dispatch_sync(main_queue, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncMain = 2--%@",[NSThread currentThread]);
}
});
dispatch_sync(main_queue, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"syncMain = 3--%@",[NSThread currentThread]);
}
});


NSLog(@"同步執行 + 主佇列 ---end %@",[NSThread currentThread]);

}
執行結果：
---begin <NSThread: 0x6000011b6940>{number = 1, name = main}

第六種 --> 非同步執行 + 主佇列在主執行緒中依次執行
| 執行結果 --> 先執行主線(begin,end)，然後依次執行任務

- (void)asyncMainThread
{
NSLog(@"非同步執行 + 主佇列 ---begin %@",[NSThread currentThread]);

dispatch_queue_t main_queue = dispatch_get_main_queue();
dispatch_async(main_queue, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncMain = 1--%@",[NSThread currentThread]);
}
});
dispatch_async(main_queue, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncMain = 2--%@",[NSThread currentThread]);
}
});
dispatch_async(main_queue, ^{
for (int i = 0; i < 3; i++) {
NSLog(@"asyncMain = 3--%@",[NSThread currentThread]);
}
});
NSLog(@"非同步執行 + 主佇列 ---end %@",[NSThread currentThread]);
}
執行結果：
非同步執行 + 主佇列 ---begin <NSThread: 0x6000018f6980>{number = 1, name = main}
非同步執行 + 主佇列 ---end <NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 1--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 1--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 1--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 2--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 2--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 2--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 3--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 3--<NSThread: 0x6000018f6980>{number = 1, name = main}
asyncMain = 3--<NSThread: 0x6000018f6980>{number = 1, name = main}

iOS GCD多執行緒

執行緒建立的6中方式

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