【学习笔记】Google JobScheduler Demo的学习与运用

官方 DEMO

路径如下

sdk\sources\android-22\com\android\demo\jobSchedulerApp\

Demo 需求

JobShedule的出发点是提供省电场景给用户进行任务完成，目前主要场景如下
1.网络数据场景
2.充电场景
3.idle待机场景
4.固定周期场景

接下来我们已
充电下且网络为连接时的场景为例进行JobShedule的使用说明。

Demo中的源代码都是Google SDK自带的

核心设置参数代码如下

        // 设置最小的延迟时间        builder.setMinimumLatency(1*1000);        // 设置最大的延迟时间，一旦设置了这个属性，不管其他条件怎么样，jobinfo到了时间就一定会执行。        builder.setOverrideDeadline(5*1000);        // 设置在什么样的网络下启动jobinfo        builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED);        // 设置设备需要在空闲的时候，是否启动job        builder.setRequiresDeviceIdle(false);        // 设置是否充电情况下调度        builder.setRequiresCharging(true);

备注：上述的关系是与的关系，不是或的关系

场景条件达成回调接口如下

public class MyJobSchedulerService extends JobService{    /**     * 满足Job预设置条件下回调      */    @Override    public boolean onStartJob(JobParameters jobParameters) {        Log.d(Constant.TAG, "onStartJob: " + jobParameters.getJobId());    }    /**     * 1.被CancleAll的时候回调     * 2.不满足预设置条件的情况下回调     */    @Override    public boolean onStopJob(JobParameters jobParameters) {    }}

重要权限

    <service android:name=".service.MyJobSchedulerService"        android:permission="android.permission.BIND_JOB_SERVICE"/>

    /**     * Job services must be protected with this permission:     *     * <pre class="prettyprint">     *     &#60;service android:name="MyJobService"     *              android:permission="android.permission.BIND_JOB_SERVICE" &#62;     *         ...     *     &#60;/service&#62;     * </pre>     *     * <p>If a job service is declared in the manifest but not protected with this     * permission, that service will be ignored by the OS.     */    public static final String PERMISSION_BIND =            "android.permission.BIND_JOB_SERVICE";

JobScheduler参数设置指令

public void scheduleJob(View v) {        if (!ensureJobSchedulerService()) {            return;        }        JobInfo.Builder builder = new JobInfo.Builder(kJobId++, mServiceComponent);        /**         * Specify that this job should be delayed by the provided amount of time.         * Because it doesn't make sense setting this property on a periodic job, doing so will         * throw an {@link java.lang.IllegalArgumentException} when         * {@link android.app.job.JobInfo.Builder#build()} is called.         * @param minLatencyMillis Milliseconds before which this job will not be considered for         *                         execution.         */        // 设置最小的延迟时间        // builder.setMinimumLatency(1*1000);        /**         * Set deadline which is the maximum scheduling latency. The job will be run by this         * deadline even if other requirements are not met. Because it doesn't make sense setting         * this property on a periodic job, doing so will throw an         * {@link java.lang.IllegalArgumentException} when         * {@link android.app.job.JobInfo.Builder#build()} is called.         */        // 设置最大的延迟时间，一旦设置了这个属性，不管其他条件怎么样，jobinfo到了时间就一定会执行。        // builder.setOverrideDeadline(5*1000);        /** Default. 任意网络都可以*/        // public static final int NETWORK_TYPE_NONE = 0;        /** This job requires network connectivity. 任意网络都可以*/        // public static final int NETWORK_TYPE_ANY = 1;        /** This job requires network connectivity that is unmetered. 无线网络接入*/        // public static final int NETWORK_TYPE_UNMETERED = 2;        /** This job requires network connectivity that is not roaming. 非漫游*/        // public static final int NETWORK_TYPE_NOT_ROAMING = 3;        /** This job requires metered connectivity such as most cellular data networks. 移动数据网络 */        // public static final int NETWORK_TYPE_METERED = 4;        // 设置在什么样的网络下启动jobinfo        builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED);        /**         * Specify that to run, the job needs the device to be in idle mode. This defaults to         * false.         * <p>Idle mode is a loose definition provided by the system, which means that the device         * is not in use, and has not been in use for some time. As such, it is a good time to         * perform resource heavy jobs. Bear in mind that battery usage will still be attributed         * to your application, and surfaced to the user in battery stats.</p>         * @param requiresDeviceIdle Whether or not the device need be within an idle maintenance         *                           window.         */        // 设置设备需要在空闲的时候，是否启动job        builder.setRequiresDeviceIdle(false);        /**         * Specify that to run this job, the device needs to be plugged in. This defaults to         * false.         * @param requiresCharging Whether or not the device is plugged in.         */        // 设置是否充电情况下调度        builder.setRequiresCharging(true);        /**         * Set whether or not to persist this job across device reboots.         *         * @param isPersisted True to indicate that the job will be written to         *            disk and loaded at boot.         */        // 设置是否重启后继续调度，注意设置true是需要添加重启权限        builder.setPersisted(false);        /**         * 我设置了充电下且网络连接时才触发onJobStart()的条件         * 注意：上述的条件是与的关系，不是或         */        Log.d(Constant.TAG, "设置充电下且网络连接的条件");        tv_info.setText("设置充电下且网络连接的条件");        myJobSchedulerService.schedulejob(builder.build());    }

结束Job任务指令

结束所有JOB

    /**     * 杀死在这个包里注册的所有的jobinfo     * @param v     */    public void cancelAllJobs(View v) {        JobScheduler tm = (JobScheduler) getSystemService(Context.JOB_SCHEDULER_SERVICE);        /**         * Cancel all jobs that have been registered with the JobScheduler by this package.         *         * 备注：这里会回调onStopJob();         */        tm.cancelAll();        tv_info.setText("杀死在这个包里注册的所有的jobinfo");    }

结束指定JOB

    public void callJobFinished() {        if (mJobParametersMap.size() == 0) {            return ;        }        JobParameters params = mJobParametersMap.valueAt(0);        if (params == null) {            return;         } else {            /**             * Call this to inform the JobManager you've finished executing. This can be called from any             * thread, as it will ultimately be run on your application's main thread. When the system             * receives this message it will release the wakelock being held.             * <p>             *     You can specify post-execution behaviour to the scheduler here with             *     <code>needsReschedule </code>. This will apply a back-off timer to your job based on             *     the default, or what was set with             *     {@link android.app.job.JobInfo.Builder#setBackoffCriteria(long, int)}. The original             *     requirements are always honoured even for a backed-off job. Note that a job running in             *     idle mode will not be backed-off. Instead what will happen is the job will be re-added             *     to the queue and re-executed within a future idle maintenance window.             * </p>             *             * @param params Parameters specifying system-provided info about this job, this was given to             *               your application in {@link #onStartJob(JobParameters)}.             * @param needsReschedule True if this job should be rescheduled according to the back-off             *                        criteria specified at schedule-time. False otherwise.             */            /**             * 告诉JobManager 已经完成了工作，如果第二个参数为false，就是不需要重试这个jobinfo，             *   第二个参数为true,相当于告诉系统任务失败，需要重试，而且与要遵守之前的jobinfo.             *                * 备注：这里不会回调onStopJob();            */            jobFinished(params, false);            String result = "callJobFinished getJobId = " + params.getJobId();            Log.d(Constant.TAG, result);            if (null != mainActivity) {                mainActivity.onReceivedJobFinished(result);            }            mJobParametersMap.removeAt(0);        }    }

Job回调事件

预设置条件满足事件回调

    /**     *  满足Job预设置条件下回调      */    @Override    public boolean onStartJob(JobParameters jobParameters) {        Log.d(Constant.TAG, "当前满足预设置条件，故触发 onStartJob: " + jobParameters.getJobId());        mCurrentId ++;        mJobParametersMap.put(mCurrentId, jobParameters);        if (null != mainActivity) {            mainActivity.onReceivedStartJob(jobParameters);        }        return true;    }

预设置条件不满足事件回调

    /**     * 1.被CancleAll的时候回调     * 2.不满足预设置条件的情况下回调     */    @Override    public boolean onStopJob(JobParameters jobParameters) {        Log.d(Constant.TAG, "不满足预设置条件， onStopJob : " + jobParameters.getJobId());        int id = mJobParametersMap.indexOfValue(jobParameters);        mJobParametersMap.remove(id);        if (null != mainActivity) {            mainActivity.onReceivedStopJob(jobParameters);        }        return false;    }

结语

个人任务Job本质提供合适的省电场景，让应用执行一些费时且优先级不是很高的事情，比如备份，数据上传等等，当然不建议利用这个特性进行保活，即利用该机制完成应用的频繁启动，这样就违背Google的初衷了

Demo下载

http://download.csdn.net/download/su749520/10130262