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Show a progress bar when an Activity is loading

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I have a ListActivity which launches another Activity based on the list selection. This second Activity needs to load a fair bit of data from the internet and as such there is a noticeable delay between when the user clicks on an item and when the Activity displays.

This is a problem because I currently have no way to indicate to the user that their click is being processed (even just changing the colour of the selected list item would be sufficient but I can't find a good way to do that). Ideally I'd be able to display an indeterminate ProgressDialog while the second Activity is loading.

I've tried a few different approaches for this but nothing seems to work as desired.


I've tried the following:

  • Retrieving the serializable data (not all of it but some part) in an AsyncTask in the first Activity and passing it as an extra to the second. This didn't really work well as a ProgressDialog I created in onPreExecute() didn't display immediately (it seems delayed by the processing done in doInBackground() for some reason.)

Here is the code for that:

AsyncTask<String, Void, String> read = new AsyncTask<String, Void, String>() {
    Dialog progress;

    @Override
    protected void onPreExecute() {
        progress = ProgressDialog.show(SearchActivity.this, 
                "Loading data", "Please wait...");
        super.onPreExecute();
    }

    @Override
    protected String doInBackground(String... params) {
        DatasetReader reader = new DatasetReader();
        reader.setFundID(params[0]);
        reader.addDatsets(FundProfile.datasets);
        reader.populate();
        return reader.toString();
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        progress.dismiss();
    }
};
read.execute(selectedItem.getUniqueID());
try {
    action = new Intent(SearchActivity.this, FundProfile.class);
    action.putExtra("data", read.get());
} catch(Exception ex) {
    ex.printStackTrace();
}
  • In the second Activity's onCreate() method (this does not work at all):

    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setProgressBarVisibility(true);

Here is the onCreate() method for the second approach:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setTitleColor(Color.WHITE);
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setProgressBarVisibility(true);

    try {
        setContentView(R.layout.fund_profile);
        // init some data
        setProgressBarVisibility(false);
    } catch(Exception ex) {
        FundProfile.this.finish();
    }
}
like image 627
Adam Avatar asked Feb 01 '11 19:02

Adam


People also ask

How can we display progress bar in Android?

Modify src/MainActivity. java file to add progress code to display the progress dialog. Modify res/layout/activity_main. xml file to add respective XML code.


2 Answers

If you have long operations you should not be doing them in onCreate in any case as this will freeze the UI (whether or not the activity is displayed). The UI set by onCreate will not appear and the UI will be unresponsive until after the onCreate call finishes.

It seems you can start your second activity and display a progress bar (or requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);), then start an ASyncTask which will be responsible for updating your UI once data has been retrieved.

like image 62
Damp Avatar answered Sep 23 '22 17:09

Damp


Adam,

It sounds like you are looking for the Indeterminate Progress bar: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/ProgressBar2.html

You can display this while you are loading your second Activity then set the visibility to false once the second Activity has loaded its data.

like image 25
Will Tate Avatar answered Sep 23 '22 17:09

Will Tate