Question

我有一个带有Recycler视图处理卡的活动。我有一个SwipeRefreshLayout，所以当我滑动它时，用新内容更新RecyclerView。到现在为止还挺好。

Howerver，我想每隔X秒更新一次RecyclerView，所以如果我在打开recylcerview的情况下离开活动，我忘了刷它，它也会自行更新。为此，我想到这样的事情：（我省略了必要的代码）。

包含recyclerview的主要活动安排了这样的Job：

private void scheduleJob() {

    ComponentName serviceName = new ComponentName(this, MyJobService.class);
    JobInfo jobInfo = new JobInfo.Builder(JOB_ID, serviceName)
            .setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED)
            .setRequiresDeviceIdle(false)
            .setRequiresCharging(false)
            .setPeriodic(3000)
            //.setOverrideDeadline(400) // Remove comment for faster testing.
            .build();

    JobScheduler scheduler = (JobScheduler) getSystemService(Context.JOB_SCHEDULER_SERVICE);
    int result = scheduler.schedule(jobInfo);

    if (result == JobScheduler.RESULT_SUCCESS) {
        Toast.makeText(this,"Start", Toast.LENGTH_LONG).show();
    } } }

在MyJobService内部我通过广播到我的Activity，让它知道它必须更新RecylcerView的内容。接收广播的责任是这样的内部类：

public static class MyReceiver extends BroadcastReceiver{


    @Override
    public void onReceive(Context context, Intent intent) {

        DataSource dataSource = new DataSource(context);
        items = dataSource.getItems(); // can't do this due to outter class variable
    adapter.refresh(ítems); // can't do this due to outter class variable
        Toast.makeText(context,"event",Toast.LENGTH_SHORT).show();

    }
}

问题在于我的主要活动我持有两个名为items的私有变量（即ArrayList）和适配器（它是recylcerview的适配器）我将项目传递给适配器以更新recyclerView内容。但是，因为我是在静态内部类中，我无法访问outter类变量。做正确的方法是什么？我想我太乱了，我想必须有一种最简单，更直接的方法来实现我的目标。

非常感谢

Answer 1

好吧，事实证明我太复杂了。它可以通过这样的简单处理程序来完成：

  // Create the Handler object (on the main thread by default)
    Handler handler = new Handler();
    // Define the code block to be executed
    private Runnable runnableCode = new Runnable() {
        @Override
        public void run() {
            // Do something here on the main thread
            Toast.makeText(getApplicationContext(),"Update",Toast.LENGTH_SHORT).show();
            ItemsDS itemsDS = new ItempsDS(getApplicationContext());
            items = itemsDS.getItems();
            adapter.clear();
            adapter.addAll(items);
            handler.postDelayed(runnableCode, 1000);
        }
    };

Answer 2

有两种方法可以做到这一点：

首先如@akshayBhat所述，您可以通过从BroadcastReceiver类中删除static关键字来实现：

ArrayList<String> items;
Adapter adapter;
public class MyReceiver extends BroadcastReceiver {


    @Override
    public void onReceive(Context context, Intent intent) {

        DataSource dataSource = new DataSource(context);
        items = dataSource.getItems(); // can't do this due to outter class variable
        adapter.refresh(ítems); // can't do this due to outter class variable
        Toast.makeText(context, "event", Toast.LENGTH_SHORT).show();

    }
}

其次是将当前活动状态的引用传递给BroadCast Receiver并使用该引用访问那里的ClassVariables;

ArrayList<String> items;
Adapter adapter;
public static class MyReceiver extends BroadcastReceiver {

    AboutUs mContext;

    @Override
    public void onReceive(Context context, Intent intent) {

        mContext = (AboutUs)context;
        DataSource dataSource = new DataSource(context);
        mContext.items = dataSource.getItems(); // can't do this due to outter class variable
        mContext.adapter.refresh(ítems); // can't do this due to outter class variable
        Toast.makeText(context, "event", Toast.LENGTH_SHORT).show();

    }
}

RecyclerView上的定期更新项目

2 个答案: