Develop Reference

How to enable SwipeRefreshLayout and initial loading ListView ProgressBar at same time

I have the following main.axml file
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/refresher"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:choiceMode="singleChoice"
android:id="#+id/myListView" />
<RelativeLayout
android:id="#+id/loadingPanel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:indeterminate="true" />
</RelativeLayout>
</android.support.v4.widget.SwipeRefreshLayout>
I require the ability to swipe down on my listview to refresh and also I require a "spinning circle loading animated icon" on initial load. However
if the Listview is above the relative layout as shown i do not get the spinning circle on initial load, but do get my Listview/refresh.
But if i change the RelativeLayout to be above the Listview i get the spinning circle on load but my Listview is not shown after?
In my onCreate method on the acitivity.
protected async override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
// Find view components
blogListView = FindViewById<ListView>(Resource.Id.myListView);
listViewRefresher = FindViewById<SwipeRefreshLayout>(Resource.Id.refresher);
loadingPanel = FindViewById<RelativeLayout>(Resource.Id.loadingPanel);
blogListView.Adapter = new FeedAdapter(this, _blogPosts);
//Register events
listViewRefresher.Refresh += HandleRefresh;
blogListView.ItemClick += OnListItemClick;
// Populate views
await PoplulateBlogPostsFromExternalWebUrl();
loadingPanel.Visibility = ViewStates.Gone;
}

According to the android docs SwipeRefreshLayout can only host one child. As a result the second view is always being hidden. To get this to work you will have to wrap the ListView and RelativeLayout in another RelativeLayout. It's also worth noting that the RelativeLayout wrapping the ProgressBar can probably be removed if an id is put on the ProgressBar.
The OP discovered (in the comments above) that this caused the SwipeRefreshLayout to be triggered when the list was scrolled up. To address this you would need to disable the layout when the list view is not at the top.
Sample Code:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/refresher"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<RelativeLayout
android:id="#+id/loadingContainer"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:choiceMode="singleChoice"
android:id="#+id/myListView" />
<RelativeLayout
android:id="#+id/loadingPanel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:indeterminate="true" />
</RelativeLayout>
</RelativeLayout>
</android.support.v4.widget.SwipeRefreshLayout>

Adding buttons below GraphView, all inside a Fragment

I have been trying to add Button's below a GraphView, and all these elements are part of a Fragment. Tried many approaches but none of them worked properly.
This is the layout file for the Fragment (fragment_graph.xml).
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.nma.util.sdcardtrac.GraphFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/graph_fragment_layout"
android:orientation="vertical"
/>
</FrameLayout>
And this is the Java code dynamically adding a graph and button, placed in the Fragment's onViewCreated (View view, Bundle savedInstanceState).
storageGraph = new LineGraphView(getActivity(), graphLabel);
storageGraph.addSeries(graphSeries); // More config calls follow
...
LinearLayout view = (LinearLayout)getView().findViewById(R.id.graph_fragment_layout);
Button button = new Button(getActivity());
button.setText("Test");
view.addView(storageGraph);
view.addView(button);
The Button is not visible though I have set orientation to vertical for the LinearLayout containing it.
EDIT - solved!
I found that nesting the graph under its own LinearLayout and the buttons under another LinearLayout, and both of these wrapped in a LinearLayout fixed the problem! The LinearLayout containing the graph must be weighted (I chose a weight of 0.8).
Layout file looks like:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.nma.util.sdcardtrac.GraphFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/graph_fragment_wrap"
android:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.8"
android:id="#+id/graph_fragment_layout"
android:orientation="vertical" />
<LinearLayout
android:id="#+id/graph_buttons"
android:orientation="horizontal"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:src="#drawable/ic_navigation_previous_item"/>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_navigation_next_item"/>
</LinearLayout>
</LinearLayout>
</FrameLayout>

I've just tried it and it works. Perhaps your graph is taking all the available space, so added button is below the screen? Try to wrap your LinearLayout into a ScrollView and see if there is a button in the bottom.

Floating button in Android application (Paging View)

I have an iPhone application which pages through a series of images. I use the following code to place a floating help button in my view controller, it stays in the same position on the screen as the user pages through the images:
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setImage:[UIImage imageNamed:#"Help.png"] forState:UIControlStateNormal];
[button addTarget:self
action:#selector(viewHelp)
forControlEvents:UIControlEventTouchDown];
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad){
button.frame = CGRectMake(60.0, 60.0, 210.0, 80.0);
CGRect buttonFrame = button.frame;
buttonFrame.size = CGSizeMake(70, 70);
button.frame = buttonFrame;
NSLog(#"IPAD");
}
else {
button.frame = CGRectMake(30.0, 30.0, 60.0, 40.0);
CGRect buttonFrame = button.frame;
buttonFrame.size = CGSizeMake(45, 45);
button.frame = buttonFrame;
}
[self.view addSubview:button];
I'm wondering how one can achieve the same functionality in an Android app? Below is my current layout xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:screenOrientation="portrait"
android:orientation="vertical" >
<android.support.v4.view.ViewPager
android:id="#+id/myfivepanelpager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
Can anyone give me any pointers?
EDIT: I would like to place the button just off-set of the top-left corner.

I would always recommend using a Relative Layout. Inside a RelativeLayout you can freely place Views, and they also can overlap.
Try something like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:screenOrientation="portrait" >
<android.support.v4.view.ViewPager
android:id="#+id/myfivepanelpager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<Button
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:alignParentTop="true"
android:alignParentRight="true" />
</RelativeLayout>
This layout shows the ViewPager and a button floating in the upper right corner.

You can use a relative layout, which will place the ImageButton on top of the ViewPager something like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:screenOrientation="portrait"
android:orientation="vertical" >
<android.support.v4.view.ViewPager
android:id="#+id/myfivepanelpager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ImageButton
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:src="#drawable/help" />
</RelativeLayout>

Change activity background from code

I have an activity with a background:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:minWidth="25px"
android:minHeight="25px"
android:background="#drawable/background_fingerboard" />
How can I change background image from code? I actually use mono, but Java samples will also be helpful.

first add LinearLayout id as in your layout xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/linearLayoutid"
android:minWidth="25px"
android:minHeight="25px"
android:background="#drawable/background_fingerboard"
and in code part set background as::
LinearLayout linearLayout = (LinearLayout) findViewById(R.id.linearLayoutid);
linearLayout.setBackgroundResource(R.drawable.background_fingerboard);

In java we do like this
Give id to LinearLayout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id=#+id/parentLayout
Then in code
LinearLayout layout=(LinearLayout)findViewById(R.id.parentLayout);
layout.setBackgroundColor(Color.BLUE); Or
layout.setBackgroundDrawable(d); Or
layout.setBackgroundResource(resid);

LinearLayout vi = (LinearLayout ) findViewById(<id>)
vi.setBackgroundResource(R.drawable.<id2>);
you need to provide the id to your LinearLayout in XML as well....

Android findViewById Working Sometimes

I am having a very weird glitch that I cannot get my head around. Any help will be appreciated as this works on a phone running Android 2.3, tablet running 3.1 but not on a phone running Android 2.1.
I am trying to get the LinearLayout defined in the following XML with the ID of "overview_linear_layout".
overview_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<include layout="#layout/listing_view" android:layout_width="fill_parent" android:id="#+id/header_view" android:layout_height="wrap_content"></include>
<ScrollView android:id="#+id/scrollView1" android:layout_weight="1" android:layout_width="fill_parent" android:layout_height="wrap_content">
<LinearLayout android:layout_width="fill_parent" android:orientation="vertical" android:layout_height="fill_parent" android:id="#+id/overview_linear_layout">
<TextView android:scrollbars="vertical" android:longClickable="false" android:layout_weight="1" android:clickable="false" android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="#+id/main_description"></TextView>
</LinearLayout>
</ScrollView>
<include layout="#layout/listing_view" android:layout_width="fill_parent" android:id="#+id/footer_view" android:layout_height="wrap_content" android:layout_weight="0.0"></include>
</LinearLayout>
The code I am using to get the view is as follows:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.overview_view);
LinearLayout linearLayout = (LinearLayout)findViewById(R.id.overview_linear_layout);
if(linearLayout!=null) {
System.out.println("Found linear layout");
}
else {
System.out.println("Did not find linear layout");
}
}
I have tried Project->Clean in Eclipse but that does not help either.

if eclipse don't show overview_linear_layout when you type click on the red cross and click create constant overview_linear_layout in R .

change this
LinearLayout linearLayout = (LinearLayout)findViewById(R.id.overview_linear_layout);
to
LinearLayout linearLayout = (LinearLayout)findViewById(R.layout.overview_linear_layout);`