Pull to Refresh – Part 1

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAdapter = new ArrayAdapter(this,
android.R.layout.simple_list_item_1, android.R.id.text1,
Arrays.asList(sContent));
setListAdapter(mAdapter);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
mRefresh = menu.findItem(R.id.menu_refresh);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.menu_refresh) {
item.setActionView(R.layout.layout_progress);
mHandler.postDelayed(new Runnable() {

@Override
public void run() {
refreshComplete();
}
}, 2000);
}
return super.onOptionsItemSelected(item);
}

private void refreshComplete() {
mRefresh.setActionView(null);
}

}
[/java]

This should also be pretty straightforward. What we’re doing is creating a very simple Adapter to populate our ListView, and adding a dummy “refresh” behaviour which will show the indeterminate progress for 2 seconds after the refresh button is pressed. So this would be pretty traditional refresh behaviour of a ListView.

I wanted to create the basic behaviour in order to show not only how easy it is to implement Pull-to-Refresh, but also how easy it is to retro-fit it to existing code.

To add Pull-to-Refresh, we must first import the library project from GitHub. Select ‘File|Import…|Git|Projects from Git’ then hit “Next”. Then click URI and “Next” again. In the URI field enter ‘https://github.com/chrisbanes/Android-PullToRefresh.git’, and click “Next”. Select the “master” branch then click “Next”. Keep the default values on the next page, but make a note of the directory as you’ll need it shortly, and click “Next”. Select “Use the New Project wizard” then click “Finish”.

From the wizard selection, select “Android|Android project from existing code” and click “Next”. Now click “Browse” and go to the directory that you noted earlier then select the folder within it named ‘library’ and click “OK”. You should see the library project appear in the “Projects” list, and then click “Finish”.

This will check out the library, and all we need to do is add this as a library to our app by right clicking on Pull2Refresh in Package Explorer, then selecting “Properties|Android” scrolling to the bottom, clicking “Add” selecting the library project, and clicking “OK”.

Now that we have included the library, we need to make a few small changes to our app. First we need to update our main layout to use the PullToRefreshListView instead of a standard ListView: