[SOP_多线程编程] 三种多线程的步骤 #Android

Runnable.md

通过实现 Runnable 接口的实例来创建线程

class RunnableDemo implements Runnable {
   private Thread t;
   private String threadName;
   
   RunnableDemo( String name) {
      threadName = name;
      System.out.println("Creating " +  threadName );
   }
   
   public void run() {
      System.out.println("Running " +  threadName );
      try {
         for(int i = 4; i > 0; i--) {
            System.out.println("Thread: " + threadName + ", " + i);
            // 让线程睡眠一会
            Thread.sleep(50);
         }
      }catch (InterruptedException e) {
         System.out.println("Thread " +  threadName + " interrupted.");
      }
      System.out.println("Thread " +  threadName + " exiting.");
   }
   
   public void start () {
      System.out.println("Starting " +  threadName );
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}
 
public class TestThread {
 
   public static void main(String args[]) {
      RunnableDemo R1 = new RunnableDemo( "Thread-1");
      R1.start();
      
      RunnableDemo R2 = new RunnableDemo( "Thread-2");
      R2.start();
   }   
}

通过 Runnable 接口的匿名类来创建线程

new Thread(new Runnable() {
	@Override
    public void run() {
    	// 处理具体的逻辑 (耗时)
    }
}).start();

Thread.md

基本概念

创建一个线程的第二种方法是创建一个新的类，该类继承 Thread 类，然后创建一个该类的实例。 继承类必须重写 run() 方法，该方法是新线程的入口点。它也必须调用 start() 方法才能执行。 该方法尽管被列为一种多线程实现方式，但是本质上也是实现了 Runnable 接口的一个实例。

缺点

使用继承导致耦合性高 , 不如使用接口

实例

class ThreadDemo extends Thread {
   private Thread t;
   private String threadName;
   
   ThreadDemo( String name) {
      threadName = name;
      System.out.println("Creating " +  threadName );
   }
   
   public void run() { // run() 中处理具体的逻辑
      System.out.println("Running " +  threadName );
      try {
         for(int i = 4; i > 0; i--) {
            System.out.println("Thread: " + threadName + ", " + i);
            // 让线程睡眠一会
            Thread.sleep(50);
         }
      }catch (InterruptedException e) {
         System.out.println("Thread " +  threadName + " interrupted.");
      }
      System.out.println("Thread " +  threadName + " exiting.");
   }
   
   public void start () {
      System.out.println("Starting " +  threadName );
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}
 
public class TestThread { 
   public static void main(String args[]) {
      ThreadDemo T1 = new ThreadDemo( "Thread-1");
      T1.start();
      
      ThreadDemo T2 = new ThreadDemo( "Thread-2");
      T2.start();
   }   
}