Develop Reference

Android : One background for two fragments

I try to make an app but I have an issue with the background.
The above image shows what should look like the app. Every rectangle of color is a fragment and the red one already have the correct part of the background. But now I try to figure out how can i make the green rectangle background respect this rules :
Image width needs to match parent
The image needs to keep his ratio
Image need to "stick" the bottom (in that way the upper part shows in the red rectangle won't appears in the green one)
In the green fragment I have a ConstraintLayoutand an ImageView like above :
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="#drawable/ss_background_blur"
android:adjustViewBounds="true"
android:scaleType="fitXY"/>
The #drawable/ss_background_blur is my PNG image.
Thx

As Neo Shen pointed out in the comments, the only thing you need to do is set the background property of the container element to the drawable resource (the image).
If you have an Activity which only contains three Fragment elements, then you can set the background of the main Activity layout.
You can see and clone a quick demo I put together here:
https://github.com/sipox11/full-background-android-app
This is the result:
Note: I did it very quickly so obviously the tabs are not real tabs and the top bar is not a real nav bar, but you get the idea.
In this case the background image is actually below the tabs area, but if you want it to start on top of it, you can wrap the top and middle fragments within a LinearLayout and set the background image to that container.
Hope it helps,
Cheers.

Set the background of the rootlayout to green and add android:layout_margin="2dp" to the imageview .
Hope this helps.

ImageView rotate + fill screen

I would like to fill the screen with a rotated ImageView. The question of how to fill the screen with an ImageView and how to rotate an ImageView has been answered seperately mutlipe times on the site. My XML code looks as follows.
<ImageView
android:id="#+id/video_frame"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:rotation="270"
/>
The problem is that the rotation happens after the image has been fitted with no rotation applied and I end up with an image that does not fill the screen.
I could of course just rotate the images (and remove the ImageView rotation) as follows:
Matrix mMatrix = new Matrix();
mMatrix.postRotate(-90);
ImageView video = (ImageView)findViewById(R.id.video_frame);
Bitmap frame = BitmapFactory.decodeFile("path/to/file.jpg");
Bitmap frame2 = Bitmap.createBitmap(frame, 0, 0, frame.getWidth(), frame.getHeight(), mMatrix, true);
video.setImageBitmap(frame2);
Here the problem is that the application is realtime and I am serving multipe frames per second (20+). The rotation per frame seems to be quite heavy and even if in this case the images fill the screen, the result is lagging and not as responsive as without the matrix rotation.
My question would therefore be if I could solve this issue with XML only or in any other way without rotating every image I want to display?

You can use RotateLayout and put your ImageView in RotateLayout and pass your rotation in setAngle() method of RotateLayout, So It rotates only view not Image or we can say bitmap it's much faster than any other rotation of Images.
you can add its dependency in Gradle file.
Usage
In your layout file add
<com.github.rongi.rotate_layout.layout.RotateLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:angle="90"> <!-- Specify rotate angle here -->
<YourLayoutHere
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</YourLayoutHere>
</com.github.rongi.rotate_layout.layout.RotateLayout>
Voila! Your layout will be rotated 90 degrees.
Download
compile 'rongi.rotate-layout:rotate-layout:3.0.0'
Features
Handles all touch events in a correct way. You press the same button you touch!
Layout measures itself in a correct way. This means that if the original view is 50x100, then 90 degrees rotated it will measure itself as 100x50 and can fit in another layout with this dimensions.
RotateLayout Link

Place image's over image

Im working on an android app were you can setup your own Ring.
Now I want to give the user a preview of the ring, when they selected multiple rings.
Here a preview of how it should look like
The setup of how i thought to make it is this:
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="5dp">
<ImageView
android:id="#+id/generator_ring_image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#e7e7e7"/>
<FrameLayout
android:id="#+id/generator_ring_addon_frame"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</FrameLayout>
I'm going to add the addon rings programmatically by just creating a new ImageView in the code.
Now the hard part of this is to place the image over the other ring, and have the view the same on every screen size..
Is ther anybody who can help me getting the correct code for placing the image on the correct position on every screen size?
thanks for reading
EDIT:
the moment I am selecting the addons rings the Base Rings is already visible, so I can get the height of the image

User Paint API: https://developer.android.com/reference/android/graphics/Paint.html
https://developer.android.com/reference/android/graphics/Canvas.html
Like that you can add whatever pictures you want, programatically, move them, even create animations if you want.
Also you will have just a view, which contains the canvas. So no need to have convoluted FrameLayouts into FrameLayouts.
Example on how to draw images on a canvas.
draw object/image on canvas

Using canvas you can get (x,y) coordinates of the ring.
First create canvas with ring image and than use canvas.draw() to draw another image on base image.

Android Pixel Perfect Alignment

I'm creating a bar at the top of my app much like the one above.
The graphics are embedded into the background and the numbers that represent the level etc is using TextViews.
As you can see the TextView has to be pixel(dp) perfect to fit in the center of the white bar thingy. With some margins or padding i can achieve that.
But how do games like that keep the same pixel perfect across all devices?
I know about resource qualifiers and such but some devices within the same bucket have different sizes.
Is there a good way or trick to achieve the perfect centering across most devices?

In general Android will handle the relative sizes across devices as long as you do everything in relative units and include 9-patch or images for each screensize.
For your question of how to handle images attached to a TextView, you can accomplish this a few ways.
A TextView will allow you to attach a drawable to it on the top, bottom, left, and right. You can do this with code using the various setCompoundDrawable* methods. For example, this will add a drawable to the right and left of the TextView.
txtScore.setCompoundDrawables(R.drawable.imageLeft, null, R.drawable.imageRight, null)
You can also do this in XML with the drawableLeft, etc properties. You may need to mess with padding and bounds for the drawables.
<TextView
android:id="#+id/txtScore"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:drawableLeft="#drawable/imageLeft"
android:drawableRight="#drawable/imageRight"
android:drawablePadding="10dp"
android:singleLine="true"
android:text="125"/>
There are a number of different options in code as well if you look over those setCompoundDrawable type APIs for the TextView.
Your other option is to create your own View that does all of the work for you, but may be overkill if you only use it in one spot.
Again, you will really want to consider a 9-patch image or create an image for each screensize in the drawable folders. This will allow Android to determine which image to use for each device.

Android background image

I have a background image of size 720x1280 for larger screen phones like the LG Nitro P930. However, when I have an application that displays this image, it doesn't cover about half an inch at the bottom of the screen. The image looks fine on normal and small screen sizes, and I have included all of the support screens in my manifest file.
Is there something that I can do that will allow me to stretch the image to fit the screen, or am I doing something wrong?

add android:scaleType="fitXY" and fill_parent for height and width both in you layout xml
You don't have to use image view background should work fine, are you using a scroll view per chance somewhere?

I figured it out. It was actually a setting on the phone that optimizes the application.