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:
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();
}
}
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.
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.
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.
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