在Android中实现多线程同步

1. java中对多线程访问控制可使用关键字synchronized
下面将以Producer Consumer模型介绍android中线程同步的使用。

步骤：
建立一android project，
修改main activity如下：

代码：

package com.test.thread;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class MultiThread extends Activity {

    private static final String MultiThread_ACTIVITY_TAG = "MultiThread_TAG";
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        CubbyHole c = new CubbyHole();
        Producer p1 = new Producer(c, 1);
        Consumer c1 = new Consumer(c, 1);

        p1.start();
        c1.start();

        // Test log system.
        //testLog();

        setContentView(R.layout.main);

    }

    // This is a example to use android.util.Log.
    public void testLog() {
        Log.i(MultiThread_ACTIVITY_TAG, "=============================");

        Log.d(MultiThread_ACTIVITY_TAG, "this is a DEBUG of MyAndroid. ");
        Log.i(MultiThread_ACTIVITY_TAG, "this is a INFO of MyAndroid. ");
        Log.w(MultiThread_ACTIVITY_TAG, "this is a WARNING of MyAndroid. ");
    }


    public class Producer extends Thread {
        private CubbyHole cubbyhole;
        private int number;

        public Producer(CubbyHole c, int number) {
            cubbyhole = c;
            this.number = number;
        }

        public void run() {
            for (int i = 0; i < 10; i++) {
                cubbyhole.put(i);
                Log.d(MultiThread_ACTIVITY_TAG, "Producer #" + this.number + " put: " + i);
                //System.out.println("Producer #" + this.number + " put: " + i);
                try {
                    sleep((int)(Math.random() * 100));
                } catch (InterruptedException e) {}
            }
        }
    }

    public class CubbyHole {
        private int contents;
        private boolean available = false;

        public synchronized int get() {
            while (available == false) {
                try {
                    wait();
                    } catch (InterruptedException e) { }
            }

            available = false;
            notifyAll();
            return contents;
        }

        public synchronized void put(int value) {
            while (available == true) {
                try {
                    wait();
                    } catch (InterruptedException e) { }
            }
            contents = value;
            available = true;
            notifyAll();
        }
    }


    public class Consumer extends Thread {
        private CubbyHole cubbyhole;
        private int number;

        public Consumer(CubbyHole c, int number) {
            cubbyhole = c;
            this.number = number;
        }

        public void run() {
            int value = 0;
            for (int i = 0; i < 10; i++) {
                value = cubbyhole.get();
                Log.d(MultiThread_ACTIVITY_TAG, "Consumer #" + this.number + " got: " + value);
                //System.out.println("Consumer #" + this.number + " got: " + value);
            }
        }
    }
}

2. 上面的代码中引入了android.util.Log包，以拥有debug。
运行上面的工程后，在dbg窗口的Logcat区，显示打出的log。

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/shilongdred1979/archive/2008/10/19/3080142.aspx

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