Here's the XAML that I am using for a startup screen:
<?xml version="1.0" encoding="UTF-8" ?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<item android:drawable="#android:color/black"/>
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Test"
android:gravity="center"
android:layout_gravity="center"
android:textSize="40sp"
android:textStyle="bold"
android:fontFamily="sans-serif-medium"
android:textColor="#fff"
/>
</layer-list>
I was hoping to see white text centered on a black screen. The screen is black, but instead I cannot see any text appear at all.
I understand what you are trying to do.
You want to display a plain Text on your "Splash Screen" that displays when you open an app. Since you are using Xamarin, you have access to all the native API's and you can do everything that native developers can.
Unfortunately, being able to show plain text on the splash screen is not possible in native development. Android restricted it because "the view comes from the theme. When you set up the UI for your splash activity in the theme, it is available immediately".
Why can't I have plain text on the splash screen, when I can have images? As you see over here in detail, the splash screen only accepts drawable resources. And there is no way to convert plain text into XML drawable resources.
You do have another option though. You can use a "Loading screen". You can make the app show the splash screen, then a Loading screen, and then load the right page. Let me know if that makes sense
Set background attribute to black. Either
android:background="#000"
or
android:background="#android:color/black"
I'm not used to Xamarin in specific, but if you normally want to create some sort of splash screen for your activity, as far as I know, there is no way of directly adding a TextView to it, because LayerList only supports bitmaps (image drawables) as child items. So you would have to create an .img file containing your text. Then, you can add the image with the text to the layer-list like this:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!-- This line below is for the background colour -->
<item android:drawable="#000" />
<item>
<!-- The bitmap below contains the image with the text -->
<bitmap
android:src="#drawable/my_text_on_screen"
android:gravity="center" />
</item>
</layer-list>
To see how to create an image from a text, have a look at this StackOverflow question.
Let me know of this is what you wanted to achieve! I hope this helps.
Related
Currently using the layer-list to achieve a splash screen with a drawable at the center. The app is targetting API 23+ so using bitmap is not mandatory unless it's necessary for what am trying to do. Basically I'm trying to pull off something similar to WhatsApp's new splash screen where the company reference is placed at the bottom of the screen.
But for some reason, the second image is not being shown at all even though it's visible in the Android Studio preview distorted. What I have currently is:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#color/black700" />
<item
android:drawable="#drawable/ic_app_icon"
android:gravity="center" />
<item
android:drawable="#drawable/ic_company_mark"
android:gravity="bottom|center" />
</layer-list>
As stated in the comments I've noticed that the bottom item depends on the phone resolution on some phones. Why it depends on the resolution, I don't know.
To work around you can add padding at the bottom
<item android:bottom="50dp">
for your bottom item in your layer-list and it will show up.
I haven't found a way to dynamically set the value depending on something and therefore used a value which "looks good" for most display resolutions.
I have two buttons, one of them has default style, another has custom background drawable:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<corners android:radius="4dp" />
<solid android:color="#color/green" />
</shape>
In the end buttons look like this:
So default button is somehow smaller than button with custom background, though they have same properties:
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/bg_button_rounded_green"
android:text="Positive"
android:textColor="#color/white"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Negative"/>
It seems that custom background changes minHeight. How can I make this buttons look the same?
btn_default_normal.9.png is the default Image set to default Button widget in Android from any specific platform. Find this file in you SDK installation and copy to your res folder.
Path to find android-sdk\platforms\android-APILEVEL\data\res
Default button have default 9-patch background with own margins, shadows, etc (different for different Android versions). You have to use custom background for both buttons or take one of the default 9-patch background and create similar bg for positive button.
The default Holo Android button graphic is a PNG which purposely contains padding. If you press and hold, you'll notice a glow around the button appears...which takes up that spacing.
The default 9 patch image for the button uses drawable padding. In order to mimic it in your own drawable you can use insets. Something like:
<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="#drawable/bg_button_rounded_green" android:insetBottom="10dip"
android:insetLeft="10dip" android:insetRight="10dip" android:insetTop="10dip" />
I'll let you figure out what the values should be.
I have a button background described as follows in its own "custom_easy_but.xml" in a directory res/drawable as follows:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:drawable="#drawable/but_easy_p"
android:state_pressed="true"/>
<item android:drawable="#drawable/but_easy" />
</selector>
Then I have a layout called modeselect.xml which includes the following code:
<Button
android:id="#+id/easy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:background="#drawable/custom_easy_but"
android:text="#string/Easy" />
then I have a set different sized images in files called but_easy.png and but_easy_p.png in separate directories res/drawable-large and res/drawable-normal. The code compiles, runs and displays exactly the right button background images on a variety of phones... but if I look at the file modeselect.xml using eclipse and switch to the "graphical layout" view, I do not see the background images at all, and underneath the graphical view I see
failed to parse file c:\blah\blah\res\drawable\custom_easy_but.xml
and
couldn't resolve resource #drawable/but_easy_p
How can it be that the real phones can sort out all the xml but eclipse can't?
Be sure you have set the correct Screen size in the graphical Editor. If You had chosen a screen size, where You got no resources, Your layout will not be shown.
I have an Android application that uses a MapView with an ImageButton control (to move to the user's current location) I've added in the top right-hand corner. The problem I am having is that the ImageButton control's background is too transparent, but changing it with android:background="#BBFFFFFF" alters both the size of the background and removes the blue "flash" that you normally see when the button is pressed - two qualities I wish to retain.
I start with something like this:
<RelativeLayout 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" >
<com.google.android.maps.MapView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mapview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:clickable="true"
android:apiKey="my api key"
/>
<ImageButton android:id="#+id/googlemaps_select_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_marginTop="13dp"
android:layout_marginRight="13dp"
android:src="#drawable/device_access_location_found"/>
</RelativeLayout>
Which achieves something that looks like this:
So then I add:
android:background="#BBFFFFFF"
And I get this:
Note that although this is basically the level of opacity I want, changing the background has affected the padding, and also doesn't display a blue "flash" when pressed (which obviously isn't illustrated in this question).
So my question is, how can I change just the background color/opacity in the non-pressed state, while retaining the other visual qualities of the button? I had a brief read about Android styles and themes, but can't even figure out where this button is getting its style/theme from and how I would go about just overriding the background color/opacity while retaining all of the other visual features.
Issue
When you are assigning a fixed color to the a view background, you are replacing the default background in the view by the fixed color you define.
In reality, the background of a button is not a simple fixed color. It's a state list of color or drawables, which means, depending on button status (focous, selected, pressed, etc.) a different background is used, resulting in the "flash" animation you see when button is pressed. If you replace this state list by a simple fixed color, not depending on buttons status, you get a fixed background (i.e. not changing when button is pressed).
Resolution
There is a xml parameter that can be used to change the image view's alfa (i.e. transparency) which is:
android:alpha="1"
where the value 1 above can be any float between 0 and 1, being 1 the maximum opacy.
However, I believe this is not solving your issue, because you want to change the alfa of background not the image alfa, if I correctly understood your issue. Anyway the default seems to be 1.
One possibility the should work for you is to define a selector to be used as background. The selector will choose the drawable based on his status.
Example
<?xml version="1.0" encoding="UTF-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="#android:color/darker_gray" />
<item android:drawable="#android:color/white" />
</selector>
Save the xml file above in your drawable-xxxx folder with the name my_selector
In this example I'm using standard android colors, but you can define your own colors. You need to assigne a color for each different button status that you want to have a different color.
Then you need to define your ImageView backgroung to be the selector you defined above:
<ImageButton
android:id="#+id/googlemaps_select_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginRight="13dp"
android:layout_marginTop="13dp"
android:background="#drawable/my_selector"
android:src="#drawable/device_access_location_found" />
With the above changes, the bacground color used by the button will change when the button is pressed and you can have the "flash" effect.
I ended up using a style to inherit the look of Widget.ImageButton with just a few minor tweaks for my purposes:
My /res/values/styles.xml file now looks like:
<resources>
<style name="AppTheme" parent="android:Theme.Light" />
<style name="my_loc_btn_style" parent="#android:style/Widget.ImageButton">
<item name="android:layout_marginTop">8dp</item>
<item name="android:layout_marginRight">8dp</item>
</style>
</resources>
And my layout file has:
<ImageButton android:id="#+id/googlemaps_select_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
style="#style/my_loc_btn_style"
android:src="#drawable/device_access_location_found"/>
This seems to have inherited a background from Widget.ImageButton that seems to be just slightly transparent, which is what I was after anyway, so I don't set the transparency at all now.
I am trying to make something function exactly like the send comment button on the Google Plus app. Everything is easy enough to get working, but I can't figure out the proper way to have the submit icon/button change background color when clicked. What is the best way to handle that? I assume I could do something on click on on hold to change the color manually, but I'm not sure that's the proper way to do it.
Here's a screenshot of what I am talking about (below). In the bottom right-hand corner there is a small arrow send icon. When clicked (or held), the background of the image changes to show that it has been clicked. I would like to do the same thing.
You can use an ImageButton:
In your layout you create the ImageButton, with the arrow image as src, and a selector as background.
<ImageButton android:id="#+id/someID"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/the_arrow_image"
android:background="#drawable/background_selector"/>
The selector can look something like this:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true"
android:drawable="#drawable/background_color_when_pressed" />
<item android:drawable="#drawable/background_color_when_not_pressed" />
</selector>
The arrow image has to be transparent for the background to be visible ;)