android - Progressbar 与 asyncTask 一起

Question

我想在屏幕上使用进度条而不是 progressDialog。

我在我的 XML View 文件中插入了一个进度条，我想让它在加载时显示并在不加载时禁用它。

所以我使用的是可见的，但它发生了，所以其余的数据都下来了。

我应该如何在异步任务中使用进度条？如何显示和隐藏它？

Answer 1

这是一个最详尽的例子:

public class ScreenSplash extends Activity {

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

        final ProgressBar progress = (ProgressBar)findViewById(R.id.progress);
        final TextView    textview = (TextView)findViewById(R.id.text);

        new MyWorker(this, progress, textview).execute();
    }
}


final class MyWorker extends AsyncTask<Void, Integer, Void> {
    private static final int titles[] = {R.string.splash_load_timezone,
                                         R.string.splash_load_memory,
                                         R.string.splash_load_genres,
                                         R.string.splash_load_channels,
                                         R.string.splash_load_content};
    private static final int progr[]  = {30, 15, 20, 25, 20};

    private int index;

    private final Activity parent;
    private final ProgressBar progress;
    private final TextView textview;

    public MyWorker(final Activity parent, final ProgressBar progress, final TextView textview) {
        this.parent = parent;
        this.progress = progress;
        this.textview = textview;
    }

    @Override
    protected void onPreExecute() {
        int max = 0;
        for (final int p : progr) {
            max += p;
        }
        progress.setMax(max);
        index = 0;
    }

    @SuppressWarnings("unchecked")
    @Override
    protected Void doInBackground(final Void... params) {
        /* Load timezone. this is very slow - may take up to 3 seconds. */
          ...
        publishProgress();

        /* Get more free memory. */
          ...
        publishProgress();

        /* Load channels map. */
          ...
        publishProgress();

        /* Load genre names. */
          ...
        publishProgress();


        /* Preload the 1st screen's content. */
          ...
        publishProgress();

        return null;
    }

    @Override
    protected void onProgressUpdate(final Integer... values) {
        textview.setText(titles[index]);
        progress.incrementProgressBy(progr[index]);
        ++index;
    }

    @Override
    protected void onPostExecute(final Void result) {
        parent.finish();
    }
}

要显示/隐藏进度条，请使用 progress.setVisibility(View.VISIBLE) 和 progress.setVisibility(View.GONE)。还有 View.INVISIBLE 常量；它与 GONE 的不同之处在于，您的进度条未绘制但仍占据其空间(对某些布局很有用)。