Android Priority Job Queue (Job Manager)（一）_jobmanager android-优快云博客

Android Priority Job Queue (Job Manager)（一）

一、为什么要引入Android Priority Job Queue (Job Manager)？
如今的APP开发中，几乎绝大多数APP没有不需要后台线程操作和运行的任务，Android平台自身提供了一些后台线程的编程实现模型和API。比如常见的主流后台+线程处理方式：
A、 AsyncTask，
B、 Loaders，
C、以及更复杂的Service组合线程池（Thread Pool），
D、Java的Thread结合Handler。
等等。
但是以上方式的问题很多，尤其是在耦合到Android本身的Activity或Fragment生命周期时候，要处理各种实际的场景，还有就是当在线程操作中如果处理失败，又该怎么办？有些情况，比如当用户在WIFI或者2G/3G/4G不同网络时候的不同网络加载策略。假设用户在发送一条消息到服务器，但是在线程发送过程中网络中断，在一定时延后网络又接通，此时线程又该如何决定发送任务的再次处理？如果使用Java Thread，Android本身又不允许在主线程外更新UI。如果使用Service，那么还要解决Service和，等等等诸如此类问题全部丢到线程中处理，将会额外但又不得不处理多种状态情况。
所以，为解决上述问题，就需要引入一种相对完善、可以解决后台+线程的简单易用的线程任务调度管理框架，为此引入Android Priority Job Queue (Job Manager)。
Android Priority Job Queue (Job Manager)是github上的一个Android开源项目，项目主页是：https://github.com/yigit/android-priority-jobqueue
Android Priority Job Queue (Job Manager)在其项目主页有完整的项目研究背景和作用，简单概括起来就是简化了Android涉及到的后台线程编程开发工作，使得开发者从后台线程繁琐的开发和代码维护中解脱出来，专注于业务逻辑。

二、Android Priority Job Queue (Job Manager)使用简介。

(1) Android Priority Job Queue (Job Manager)首先需要初始化和配置，在初始化和配置阶段，Android Priority Job Queue (Job Manager)类似Java线程池，写一个MyApplication继承自
Android Application，在此完成初始化。MyApplication.java：

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package zhangphil.app;
import android.app.Application;
import android.util.Log;
import com.birbit.android.jobqueue.JobManager;
import com.birbit.android.jobqueue.config.Configuration;
import com.birbit.android.jobqueue.log.CustomLogger;
/**
* Created by Phil on 2016/10/9.
*/
public class MyApplication extends Application {
private JobManager jobManager;
private static MyApplication instance;
public MyApplication() {
instance = this;
}
public static MyApplication getInstance() {
return instance;
}
@Override
public void onCreate() {
super.onCreate();
getJobManager();// ensure it is created
}
public synchronized JobManager getJobManager() {
if (jobManager == null) {
configureJobManager();
}
return jobManager;
}
private void configureJobManager() {
Configuration.Builder builder = new Configuration.Builder(this)
.customLogger(new CustomLogger() {
private static final String TAG = “zhangphil job”;
@Override
public boolean isDebugEnabled() {
return true;
}
@Override
public void d(String text, Object… args) {
Log.d(TAG, String.format(text, args));
}
@Override
public void e(Throwable t, String text, Object… args) {
Log.e(TAG, String.format(text, args), t);
}
@Override
public void e(String text, Object… args) {
Log.e(TAG, String.format(text, args));
}
@Override
public void v(String text, Object… args) {
}
})
.minConsumerCount(1)//always keep at least one consumer alive
.maxConsumerCount(3)//up to 3 consumers at a time
.loadFactor(3)//3 jobs per consumer
.consumerKeepAlive(120);//wait 2 minute
jobManager = new JobManager(builder.build());
}
}

package zhangphil.app;

import android.app.Application;
import android.util.Log;

import com.birbit.android.jobqueue.JobManager;
import com.birbit.android.jobqueue.config.Configuration;
import com.birbit.android.jobqueue.log.CustomLogger;

/**
 * Created by Phil on 2016/10/9.
 */
public class MyApplication extends Application {
    private JobManager jobManager;

    private static MyApplication instance;

    public MyApplication() {
        instance = this;
    }

    public static MyApplication getInstance() {
        return instance;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        getJobManager();// ensure it is created
    }

    public synchronized JobManager getJobManager() {
        if (jobManager == null) {
            configureJobManager();
        }

        return jobManager;
    }

    private void configureJobManager() {
        Configuration.Builder builder = new Configuration.Builder(this)
                .customLogger(new CustomLogger() {
                    private static final String TAG = "zhangphil job";

                    @Override
                    public boolean isDebugEnabled() {
                        return true;
                    }

                    @Override
                    public void d(String text, Object... args) {
                        Log.d(TAG, String.format(text, args));
                    }

                    @Override
                    public void e(Throwable t, String text, Object... args) {
                        Log.e(TAG, String.format(text, args), t);
                    }

                    @Override
                    public void e(String text, Object... args) {
                        Log.e(TAG, String.format(text, args));
                    }

                    @Override
                    public void v(String text, Object... args) {

                    }
                })
                .minConsumerCount(1)//always keep at least one consumer alive
                .maxConsumerCount(3)//up to 3 consumers at a time
                .loadFactor(3)//3 jobs per consumer
                .consumerKeepAlive(120);//wait 2 minute

        jobManager = new JobManager(builder.build());
    }
}

实际上在自己的项目中，Android Priority Job Queue (Job Manager)的初始化工作基本上不用做修改大体按照上面的写就好了，调整的地方在于任务数量这些有关系统性能开销的地方控制。
写完了记得要在Androidmainfest.xml写到application下面：

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<?xml version=“1.0” encoding=“utf-8”?>
<manifest xmlns:android=“http://schemas.android.com/apk/res/android”
package=“zhangphil.app”>
<application
android:name=“.MyApplication”
android:allowBackup=“true”
android:icon=“@mipmap/ic_launcher”
android:label=“@string/app_name”
android:supportsRtl=“true”
android:theme=“@style/AppTheme”>
<activity android:name=“.MainActivity”>
<intent-filter>
<action android:name=“android.intent.action.MAIN” />
<category android:name=“android.intent.category.LAUNCHER” />
</intent-filter>
</activity>
</application>
</manifest>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="zhangphil.app">

    <application
        android:name=".MyApplication"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

（2）写一个请求的任务逻辑，这是Android Priority Job Queue (Job Manager)使用的关键地方。首先需要继承自Android Priority Job Queue (Job Manager)得Job类，我写了一个测试的MyJob类，在此类中用于完成后台+线程的任务操作，Android Priority Job Queue (Job Manager)的Job有些类似于Java的Runnable，可以比照Java的Runnable理解Android Priority Job Queue (Job Manager)的Job。耗时线程任务在onRun里面做，MyJob.java：

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package zhangphil.app;
import android.os.SystemClock;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;
import com.birbit.android.jobqueue.Job;
import com.birbit.android.jobqueue.Params;
import com.birbit.android.jobqueue.RetryConstraint;
/**
* Created by Phil on 2016/10/9.
*/
public class MyJob extends Job {
private String tag;
public MyJob(String tag) {
super(new Params(500).requireNetwork().persist().groupBy(tag));
this.tag = tag;
Log.d(tag, ”初始化”);
}
@Override
public void onAdded() {
Log.d(tag, ”添加任务”);
}
//在这里面放置耗时的后台线程化任务
@Override
public void onRun() throws Throwable {
Log.d(tag, ”开始运行…”);
int i = 0;
while (true) {
i++;
SystemClock.sleep(2000);
Log.d(tag, String.valueOf(i));
if (i == 10)
break;
}
Log.d(tag, ”完成”);
}
@Override
protected RetryConstraint shouldReRunOnThrowable(@NonNull Throwable throwable, int runCount, int maxRunCount) {
// An error occurred in onRun.
// Return value determines whether this job should retry or cancel. You can further
// specify a backoff strategy or change the job’s priority. You can also apply the
// delay to the whole group to preserve jobs’ running order.
Log.d(tag, ”runCount：” + runCount);
return RetryConstraint.createExponentialBackoff(runCount, 1000);
}
@Override
protected void onCancel(int cancelReason, @Nullable Throwable throwable) {
}
}

package zhangphil.app;

import android.os.SystemClock;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;

import com.birbit.android.jobqueue.Job;
import com.birbit.android.jobqueue.Params;
import com.birbit.android.jobqueue.RetryConstraint;

/**
 * Created by Phil on 2016/10/9.
 */
public class MyJob extends Job {

    private String tag;

    public MyJob(String tag) {
        super(new Params(500).requireNetwork().persist().groupBy(tag));
        this.tag = tag;
        Log.d(tag, "初始化");
    }

    @Override
    public void onAdded() {
        Log.d(tag, "添加任务");
    }

    //在这里面放置耗时的后台线程化任务
    @Override
    public void onRun() throws Throwable {
        Log.d(tag, "开始运行...");

        int i = 0;
        while (true) {
            i++;

            SystemClock.sleep(2000);
            Log.d(tag, String.valueOf(i));
            if (i == 10)
                break;
        }

        Log.d(tag, "完成");
    }

    @Override
    protected RetryConstraint shouldReRunOnThrowable(@NonNull Throwable throwable, int runCount, int maxRunCount) {
        // An error occurred in onRun.
        // Return value determines whether this job should retry or cancel. You can further
        // specify a backoff strategy or change the job's priority. You can also apply the
        // delay to the whole group to preserve jobs' running order.

        Log.d(tag, "runCount：" + runCount);

        return RetryConstraint.createExponentialBackoff(runCount, 1000);
    }

    @Override
    protected void onCancel(int cancelReason, @Nullable Throwable throwable) {

    }
}

（3）测试的MainActivity.java：

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package zhangphil.app;
import android.app.Activity;
import android.os.Bundle;
import com.birbit.android.jobqueue.JobManager;
public class MainActivity extends Activity {
private JobManager jobManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
jobManager=MyApplication.getInstance().getJobManager();
jobManager.addJobInBackground(new MyJob(“任务1”)); //启动任务，跑！
//jobManager.addJobInBackground(new MyJob(“任务2”));
//jobManager.addJobInBackground(new MyJob(“任务3”));
//jobManager.addJobInBackground(new MyJob(“任务4”));
//jobManager.addJobInBackground(new MyJob(“任务5”));
//jobManager.addJobInBackground(new MyJob(“任务6”));
}
}

package zhangphil.app;

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

import com.birbit.android.jobqueue.JobManager;

public class MainActivity extends Activity {

    private JobManager jobManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);

        jobManager=MyApplication.getInstance().getJobManager();

        jobManager.addJobInBackground(new MyJob("任务1")); //启动任务，跑！
        //jobManager.addJobInBackground(new MyJob("任务2"));
        //jobManager.addJobInBackground(new MyJob("任务3"));
        //jobManager.addJobInBackground(new MyJob("任务4"));
        //jobManager.addJobInBackground(new MyJob("任务5"));
        //jobManager.addJobInBackground(new MyJob("任务6"));
    }
}

附录我写的Android线程相关文章：
【1】《Java线程池：ExecutorService，Executors》链接地址：http://blog.youkuaiyun.com/zhangphil/article/details/43898637
【2】《Java线程池及Future、Callable获得线程返回结果【Java线程池系列2】》链接地址：http://blog.youkuaiyun.com/zhangphil/article/details/49701219
【3】《Java线程池之FutureTask【Java线程池系列3】》链接地址：http://blog.youkuaiyun.com/zhangphil/article/details/49702751