線程狀態轉換圖：

幾個容易混淆概念的方法

Thread.sleep()、 Thread.join() 或 Object.wait()，
他們都是阻塞方法並聲明拋出 InterruptedException.
當線程調用這些方法進入阻塞狀態後，如果外部調用了interrupt(),
線程進入就緒狀態，並且這些方法拋出InterruptedException異常。

<code>public void Thread.interrupt() // 設置線程的中斷狀態flag.
public boolean Thread.isInterrupted() // 獲取線程的中斷狀態flag值
public static boolean Thread.interrupted() // 取線程的中斷狀態flag值，並重置flag值為false.
public final void join() throws InterruptedException  //指的是調用者進入阻塞狀態, 而不是線程對象進入阻塞狀態, 線程對象繼續在執行， 不受影響， 看下面的例子.
public static void yield(); //線程從運行狀態， 回到就緒狀態./<code>

<code>//demo: join()
public class BottomBarManager {
    private final Object handlePopupMenuAction(int actionCode, Object... args) {
    switch (actionCode) {
            case Actions.MenuContainer.DOWNLOAD: // 下載
                ThreadTest tt = new ThreadTest();
                tt.start();
                try {
                    tt.join();  //當前線程等待tt線程執行完再往下執行
                    //作用是, 當前的UI線程進入阻塞狀態， 直到等tt線程執行完再往下繼續執行, tt線程該幹什麼還幹什麼， 不受影響. 

                    //千萬不要誤理解成tt線程進入了阻塞狀態.
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                JLog.i();
            break;

    }

    private class ThreadTest extends Thread {

        @Override
        public void run() {
            try {
                sleep(100000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            JLog.i();
        }
    }

}/<code>

中斷線程的最佳實踐是: 中斷 + 條件變量。

最佳模板：

<code>public class BestPractice extends Thread {
    private volatile boolean finished = false;   // ① volatile條件變量
    public void stopMe() {
        finished = true;    // ② 發出停止信號
        interrupt();
    }
    @Override
    public void run() {
        while (!finished) {    // ③ 檢測條件變量
        try {
                // do dirty work   // ④業務代碼
        } catch (InterruptedException e) {
                if (finished) {
                    return;
                } 

                continue;
        }
        }
    }
}/<code>

當④處的代碼阻塞於wait()或sleep()時，線程不能立刻檢測到條件變量。因此②處的代碼最好同時調用interrupt()方法。

典型的體現是在volley項目中：

<code>// CacheDispatcher.java
public class CacheDispatcher extends Thread {
    private volatile boolean mQuit = false;

    public void quit() {
        mQuit = true;
        interrupt();
    }

    @Override
    public void run() {
        Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);

        // Make a blocking call to initialize the cache.
        mCache.initialize();

        while (true) {
            try {
                // Get a request from the cache triage queue, blocking until
                // at least one is available.
                final Request> request = mCacheQueue.take(); //****** block方法, it throws InterruptedException;
                request.addMarker("cache-queue-take");

                // Attempt to retrieve this item from cache.
                Cache.Entry entry = mCache.get(request.getCacheKey());
                if (entry == null) {
                    request.addMarker("cache-miss");
                    // Cache miss; send off to the network dispatcher.
                    mNetworkQueue.put(request);
                    continue;
                }

                // We have a cache hit; parse its data for delivery back to the request. 

                request.addMarker("cache-hit");
                Response> response = null;
                try {
                    response = request.parseNetworkResponse(
                            new NetworkResponse(entry.data, entry.responseHeaders));
                } catch (Exception e) {
                    mDelivery.postError(request, new ParseError(e));
                    continue;
                } catch (Error error) {
                    mDelivery.postError(request, new ParseError(error));
                    continue;
                }
                request.addMarker("cache-hit-parsed");

            } catch (InterruptedException e) {
                // We may have been interrupted because it was time to quit.
                if (mQuit) {
                    return;
                }
                continue;
            } catch (OutOfMemoryError error) {
                if (mQuit) {
                    return;
                }
                continue;
            }
        }
    }

}/<code>