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MyBookshelf扩展Activity并实现了一个由异步下载和解压缩过程调用的接口。

异步下载过程定期onBookDownloadPercent(float)从接口调用。我的活动定义包括：

public class MyBookshelf extends Activity implements BookDownloadListener {

    private ProgressBar mProgress;

    // .......
    // .......

    @Override
    public void onBookDownloadPercent(float _percent_finished) {
        final float final_percent  = _percent_finished;
        runOnUiThread(new Runnable() {
            public void run()
            {
                DebugLog.d(TAG, "onBookDownloadPercent " + Float.toString(final_percent));
                mProgress.setProgress((int) final_percent);
            }
        });
    }
}

在 LogCat 中，我的函数DebugLog.d向我保证 UI 线程正在调用mProgress.setProgress()：

09-30 11:37:06.698: DEBUG/MyBookshelf(2069): onBookDownloadPercent 0.0014221431; thread 1
09-30 11:37:07.288: DEBUG/MyBookshelf(2069): onBookDownloadPercent 1.0004596; thread 1
09-30 11:37:07.838: DEBUG/MyBookshelf(2069): onBookDownloadPercent 2.0001705; thread 1
09-30 11:37:08.318: DEBUG/MyBookshelf(2069): onBookDownloadPercent 3.0014038; thread 1
09-30 11:37:09.098: DEBUG/MyBookshelf(2069): onBookDownloadPercent 4.0002813; thread 1
09-30 11:37:09.468: DEBUG/MyBookshelf(2069): onBookDownloadPercent 5.0003366; thread 1
09-30 11:37:09.818: DEBUG/MyBookshelf(2069): onBookDownloadPercent 6.0003924; thread 1
09-30 11:37:10.158: DEBUG/MyBookshelf(2069): onBookDownloadPercent 7.0004926; thread 1
09-30 11:37:10.588: DEBUG/MyBookshelf(2069): onBookDownloadPercent 8.000748; thread 1
09-30 11:37:10.938: DEBUG/MyBookshelf(2069): onBookDownloadPercent 9.000215; thread 1
09-30 11:37:11.368: DEBUG/MyBookshelf(2069): onBookDownloadPercent 10.00017; thread 1

对于异步解压缩任务，我有一个类似的接口：

@Override
public void onBookUnzipPercent(float _percent_finished) {
    final float final_percent  = _percent_finished;
    runOnUiThread(new Runnable() {
        public void run()
        {
            DebugLog.d(TAG, "onBookUnzipPercent " + Float.toString(final_percent));
            mProgress.setProgress((int) final_percent);
        }
    });
}

首先，MyBookshelf调用下载第一本书的异步任务，进度条正确更新（0到100%）。

其次，MyBookshelf调用解压第一本书的异步任务，进度条正确更新（0到100%）。

第三，MyBookshelf呼唤startActivity(nextIntent)读书，呼唤finish()自己。

四、读完书回到MyBookshelf：

nextIntent = new Intent(getBaseContext(), MyBookshelf.class);

当我下载下一本书时出现问题：下载发生，并且 LogCat 记录更新，但进度条仅显示为空白灰色，并且在下载或解压缩下一本书时不会更新。我已经通过 LogCat 确认线程 1 确实通过onBookDownloadPerecent Runnable

mProgress回来时我是否需要做一些有趣的事情，MyBookshelf以便在更新时显示？

4

2 回答 2

1

我的解决方案是使 mProgressBar 静态：

public class MyBookshelf extends Activity implements BookDownloadListener {

    static private ProgressBar mProgress;

    // .......
    // .......

    @Override
    public void onBookDownloadPercent(float _percent_finished) {
        final float final_percent  = _percent_finished;
        runOnUiThread(new Runnable() {
            public void run()
            {
                DebugLog.d(TAG, "onBookDownloadPercent " + Float.toString(final_percent));
                mProgress.setProgress((int) final_percent);
            }
        });
    }
}
于 2011-10-01T02:28:29.103 回答
0

为什么在阅读完这本书后回到 myBookShelf 时不使用 finish()？

看起来一切正常，但是我对这行代码有点怀疑

nextIntent = new Intent(getBaseContext(), MyBookshelf.class);

于 2011-09-30T03:42:57.080 回答