Android SDK - 在后台运行功能

Question

我有一个功能,可以在完成所需的时间内变化.我希望在此功能运行时显示进度对话框.

我知道你可以使用'Thread'来实现这一目标.有人能指出我这样做的正确方向吗？

编辑:这是我正在使用的代码:

private class LongOperation extends AsyncTask<String, Void, String> 
{
    ProgressDialog dialog;
    public Context context;
    @Override
    protected String doInBackground(String... params) {
        if (!dialog.isShowing())
            dialog.show(); // Just in case
        return null;
    }

    /* (non-Javadoc)
     * @see android.os.AsyncTask#onPostExecute(java.lang.Object)
     */
    @Override
    protected void onPostExecute(String result) {
        dialog.dismiss();
    }

    /* (non-Javadoc)
     * @see android.os.AsyncTask#onPreExecute()
     */
    @Override
    protected void onPreExecute() 
    {
        dialog = ProgressDialog.show(context, "Working", "Getting amenity information", true);
    }

    /* (non-Javadoc)
     * @see android.os.AsyncTask#onProgressUpdate(Progress[])
     */
    @Override
    protected void onProgressUpdate(Void... values) {
      // Things to be done while execution of long running operation is in progress. For example updating ProgessDialog
     }
}

这是Asnyc课程.用户从菜单中选择一个选项,然后执行:

longOperation.execute(""); // Start Async Task

GetAmenities(Trails.UserLocation); // Long function operation

Answer 1

你应该AsyncTask为此目的使用.请参阅Android开发人员网站和如何使用AsyncTask.

一些示例代码:

private class LongRunningTask extends AsyncTask<Void, Boolean, Boolean> {

    private ProgressDialog progress;

    protected void onPreExecute() {
        progress = ProgressDialog.show(yourContext, "Title", "Text");
    }

    @Override
    protected Boolean doInBackground(Void... params) {
        return true;
    }

    protected void onPostExecute(Boolean result) {
        if(result) {
           progress.dismiss();
        }
    }

}