从光标onLoadFinished填充部件（） [英] Populate widgets from a cursor in onLoadFinished()

问题描述

我想知道如何使用 CursorLoader 来填充屏幕上的小部件。所有的例子在网上只使用一个适配器来完成这项工程。我需要的是一个可靠的方式来更新从游标并在UI线程上，没有有时崩溃，因为 StaleDataException 或光标被停用所有的在我屏幕的意见突然了。这是我目前的做法，但我仍然收到来自用户的一些崩溃报告。

I want to know how to use the CursorLoader to populate the widgets on a screen. All the examples online are only for using an adapter and this works great. What I need is a reliable way to update the views in my screen from a Cursor and on the UI thread and without sometimes crashing because of StaleDataException or the cursor being deactivated all of a sudden. Here is my current approach but I still receive some crash reports from users.

@Override
    public Loader<Cursor> onCreateLoader(int id, Bundle arg1) {
        CursorLoader loader = null;

        switch (id) {
            case LOADER_ID_DATA:
                loader = new CursorLoader(...);
                break;
        }

        return loader;
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, final Cursor cursor) {
        handler.post(new Runnable() {

            @Override
            public void run() {
                if (getActivity() == null)
                    return;

                updateView(cursor);
            }
        });
    }

    @Override
    public void onLoaderReset(Loader<Cursor> arg0) {
    }

一个解决办法是直接检索所有光标领域内onLoadFinished和​​它们传递到处理程序，以填充小部件的UI线程。但是，这是丑陋的，因为我可以有很多值的光标。我很想找到应对这一切的可靠的碰撞自由的方式。

One solution would be to retrieve all the cursor fields directly inside onLoadFinished and pass them all to the handler to populate the widgets on the UI thread. But this is ugly because I may have a lot of values in the cursor. I would love to find a reliable crash-free way of dealing with all this.

推荐答案

要求在＃后的And​​r​​oid开发 SimonVT 和自述帮助我拿到这条底线。

After asking on #android-dev SimonVT and readme helped me to get the bottom of this.

没有什么，指出 onLoadFinished 将被称为UI线程因此从理论上讲，你应该使用处理程序建议一样在雷托的书。然而，当使用 CursorLoader （这是迄今为止最常见的情况），您可以pretty的多少保证 onLoadFinished 将被称为在UI线程。

There is nothing that states that onLoadFinished will be called on the UI thread so in theory you should use a Handler like advised in Reto's book. However, when using a CursorLoader (which is by far the most common use case) you can pretty much guarantee that onLoadFinished will be called in the UI thread.

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