>>439
もっとシンプルにしてやろうw

- (void)methodA:(UIButton *)sender {
[sender setTitle:@"実行中" forState:UIControlStateNormal];
[self performSelectorInBackground:@selector(methodB:) withObject:sender];
}

- (void)methodB:(UIButton *)button {
//時間のかかる処理
[button setTitle:@"完了" forState:UIControlStateNormal];
}