I'm trying to get into Android app development and as a test I'm trying to make an app download a simple web page in the background, while the main UI can be used. The user presses a 'search' button and the page is downloaded in a background task.
The code I have for this is as follows:
DownloadTask.java
//all the necessary package and import statements
public class DownloadTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... urls) {
FPDownloader fpDownloader = new FPDownloader(context);
if (fpDownloader.isConnected()) {
return fpDownloader.download(urls[0]);
}
else {
return null;
}
}
}
Where FPDownloader is a class I made. It downloads a web page and returns its content as a String.
SearchButtonListener.java
public class SearchButtonListener implements View.OnClickListener {
private Activity context;
private String type;
private String category;
private String page;
public SearchButtonListener(Activity context, String type, String category, String page) {
this.context = context;
this.type = type;
this.category = category;
this.page = page;
}
public void onClick(View view) {
String url = new FPUrlBuilder().getBrowseUrl(type, category, page);
DownloadTask downloadTask = new DownloadTask(context);
String result;
TextView test = (TextView)context.findViewById(R.id.testTextView);
try {
downloadTask.execute(url);
result = downloadTask.get();
if (result != null) {
test.setText("It worked! Downloaded " + url);
}
else {
test.setText("Something went wrong while downloading the data");
}
}
catch (Exception e) {
//e.printStackTrace();
test.setText("Something went wrong while executing the download");
}
}
}
Here FPUrlBuilder is another class I made, which simply returns an url based on the parameters you provide.
(If necessary, I can provide the activity's source aswell. Also, I know I'm passing Activity instances around- is this a bad practice or not?)
The problem I'm having is that the task executes fine - the results are shown as expected - but it appears as if it's run from the main thread (the UI freezes). What am I doing wrong? And what are the best practices for this?
