iOS Development Summary (A0)-nstimer

<span id="Label3"></p><p><p>Nstimer is an ios-developed timer, easy to use, but with a few caveats</p></p><p><p>1. The two common ways to create Nstimer are</p></p><pre><pre>+ (nstimer *) timerwithtimeinterval: (nstimeinterval) ti target: (<span style="color: #0000ff;">ID</span>) atarget selector: (SEL) aselector userInfo :(<span style="color: #0000ff;">ID</span><span style="color: #000000;">) userInfo repeats: (BOOL) yesorno;</span> + (nstimer *) scheduledtimerwithtimeinterval: (nstimeinterval) ti target: (<span style="color: #0000ff;">ID</span>) atarget selector: (SEL) Aselector UserInfo: (<span style="color: #0000ff;">ID</span>) userInfo repeats: (BOOL) yesorno;</pre></pre><p><p>The first timer to be created needs to be manually added to the runloop, otherwise the timer will not work and the method added to Runloop is:</p></p><pre><pre><span style="color: #000000;"> [[nsrunloop mainrunloop] Addtimer:timer formode:runloopmode];<br></span></pre></pre><p><p>Or</p></p><pre><pre><span> </span>currentrunloop] Addtimer:timer formode:runloopmode];</pre></pre><p><p><span style="line-height: 1.5;">The difference between Mainrunloop and Currentrunlopp is</span></p></p><p><p><span style="line-height: 1.5;">-mainrunloop is the main thread of the Runloop</span></p></p><p><p><span style="line-height: 1.5;">-currentrunlopp is the runloop of the current thread</span></p></p><p><p><span style="line-height: 1.5;">There are two types of runloopmode:</span> Nsdefaultrunloopmode and <em id="__mceDel" style="line-height: 1.5;">nsrunloopcommonmodes, the difference:</em></p></p><p><p><em style="line-height: 1.5;">-nsdefaultrunloopmode, such as TableView when scrolling, the timer fails</em></p></p><p><p><em style="line-height: 1.5;">-<em id="__mceDel">the timer does not expire when Nsrunloopcommonmodes,tableview scrolling</em></em></p></p><p><p><em>For more information, refer to</em></p></p><p><p><em>Http://www.cnblogs.com/zhangjie/p/3727469.html</em></p></p><p><p><em>Http://www.cnblogs.com/zhangjie/p/3727485.html</em></p></p><p><p></p></p><p><p><span style="line-height: 1.5;">The second timer created, the system is automatically added to the Runloop (current run loop in the default Mode)</span></p></p><p><p></p></p><p><p><span style="line-height: 1.5;">2. When the timer retain target, only the timer invalidate, the target is Released.</span></p></p><p><p>For a timer that does not repeat, the timer automatically expires after execution, and for a repeating timer, manual [timer invalidate] is required;</p></p><p><p><span style="line-height: 1.5;"></span></p></p><p><p><span style="line-height: 1.5;">3. Timer time interval is approximate time, to be accurate and timely, can use Cadisplaylink (reference http://www.cnblogs.com/YouXianMing/p/4029547.html) and GCD (follow-up will specialize in summarizing GCD)</span></p></p><p><p></p></p><p><p><span style="line-height: 1.5;"></span></p></p><p><p></p></p><p><p>iOS Development Summary (A0)-nstimer</p></p></span>