Develop Reference

Shared Element in Marshmallow and Oreo have different result

I want to make a Activity of browsing pictures which likes the WeChat in Chatting Activity by shared element.
But I found that. Using the same code , the animation is very smooth in the my first phone(Android 6.0). And in the second phone(Android 8.0), the animation has a little unsmooth.
Have you ever encountered such a situation? Do you know the reason? Any Solutions?

I found in my demo, if your activity is as follows
getWindow().setSharedElementEnterTransition(TransitionInflater.from(this).inflateTransition(R.transition.changebounds_with_test))
And your transition is as follows
<?xml version="1.0" encoding="utf-8"?>
<transitionSet xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="500">
<changeBounds/>
<changeImageTransform/>
<changeClipBounds/>
<changeTransform/>
</transitionSet>
The point is the duration which is greater than 300ms(default duration). Then the animation of Shared Element is unsmooth in Oreo.
But I had not set SharedElementEnterTransition in my project, the animation is also unsmooth in Oreo.
I think my project has any logic of code that influence the animation, which leads to the duration greater than 300ms.
Now I don't use shared element, and use value animation to make transition animation.

Developing Material Design homescreen-widgets in Android

Ok, so I'm working on a very simple Android homescreen widget that fetches the latest Image from an imageboard and displays it in a imageview.
I'd like to have the option to Style this widget, to be in keeping with Googles Material design guidelines, however, I hit the following problem whilst developing and testing on my Nexus 5 running Lollipop 5.1 -
I can't seem to use a cardview in a widget. It gives me a class not found exception however I do not get such exceptions previewing the layout and my gradle has the right dependancies so I suspect it is more to do with widget compatibility?
So I did some further reading and on the Google API page about widgets it has a very specific list of views that widgets support, which did not, to my surprise include cardviews. So I've gone back to my plain old Imageview
I guess my question then sits with, how would I get this imageview to look like a material design card? EG, rounded corners, the subtle 3d effect, drop shadow, ETC. I do not wish to give the imageview a border, the edge of the image should extend to the edges and get clipped by the rounded corners.
I have tried by simply setting the style of the Imageview to be that of a cardview, but that seems to have done absolutely nada :)
Anyone has some ideas? Thank you!

you might want to have a look at the source of the google i/o app : https://github.com/google/iosched/blob/master/android/src/main/res/layout/widget.xml

This is from a long time ago, but it's very doable to make a simple card background in XML.
The way to do this is to create an cardview-esque .xml file in your drawables app resources folder.
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#color/white" />
<corners android:radius="4dp" />
</shape>
and set the background view of your Widget's XML layout as
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/widget_card_background"
android:orientation="vertical">
<.../>
</LinearLayout>
You are correct in that CardView is not an available View type for Android Widgets, but this should create the functionality you were looking for 2 years ago

Android Studio Google Map V2 fragment rendering

I tried to write a test demo for Google Map V2 in Android Studio. I followed every step from Androidhive Google Map V2 or better I think I need.
I'm using the same layout_main.xml
<?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" >
<fragment
android:id="#+id/map"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
but I'm getting always the same rendering problem:
Rendering Problems
A <fragment> tag allows a layout file to dynamically include different layouts at runtime. At layout editing time the specific layout to be used is not known. You can choose which layout you would like previewed while editing the layout...
I have absolutely no idea what's the problem. Did I forget something?
I just need to add Google services in the build.gradle like
compile 'com.google.android.gms:play-services:4.4.52'
I copied the manifest from the demo and changed the API Key.

The accepted answer is not wrong but it does not help.
As Dan wrote, Android Studio (also Version 1.0) will not display the map.
Maps needs an API key and dynamic processed code, maybe some day we will have that but so far not.
I've a 5 minute solution for those who want to see their app properly in layout preview:
To properly develop I still needed something else than a blank background.
I added overlays and buttons on top of the map, I really needed to see the map while placing elements over it.
The solution is simple:
1. Make a screenshot of your app with the map running (Power + Volume Down)
2. Download the screenshot and use an image editor to remove the top and bottom UI elements, so you will end up with only the map itself as an image.
3. Import that image into android studio drawables
4. create a new layout, name it dummy_mapviewfragment, put only a linearlayout and an imageview in
5. make the imageview "fill" the parent, and set "src" to the cropped image you just imported
6. back to your layout, add this into your Mapview Fragment xml :
tools:layout="#layout/dummy_mapviewfragment"/>
That's it, now you will have a non-interactive mapview fragment which displays a real map.
Your app will look like it looks on your mobile phone.
If you made errors in your image cropping you can "fix" it by setting the image scale to "centerCrop" so it will properly stretch out.
Update: You can get a screenshot without need to crop directly from within Androidstudio! Makes it a bit more convenient ;)

Rendering Problems
A tag <fragment> allows a layout file to dynamically include different layouts at runtime. At layout editing time the specific layout to be used is not known. You can choose which layout you would like previewed while editing the layout...
This is just the preview window telling you that it can't display a preview for the <Fragment.../> tag, because it doesn't know what kind of fragment you're going to put in it. You can safely ignore that message - your actual app will render the fragment fine when you run it (as long as you code it up correctly!).

Android Studio automatically offers a solution within the error description, which is adding the name of the fragment layout.
tools:layout="#layout/fragment_my"

Add a dummy layout "#android:layout/simple_gallery_item" as:
<fragment
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:layout_width="317dp"
android:layout_height="385dp"
android:id="#+id/map"
tools:context="com.example.XYZ.googlemaps.MapsActivity"
android:name="com.google.android.gms.maps.SupportMapFragment"
tools:layout="#android:layout/simple_gallery_item"/>

image on top of button android

Is it possible to add an image(view) on top of a button (which as a background image)?
I'm porting an iOS app to Android and it wasn't a problem on iOS, but I'm wondering if it is the right approach on Android because of layouts.
Edit :
To clarify, check this screen shot :
http://a4.mzstatic.com/us/r1000/062/Purple/v4/7c/4b/cd/7c4bcd53-ba55-94d7-a26c-ce1bfe040003/mza_2736801523527387264.320x480-75.jpg
I need to do the bottom left button "carte" (card in french)
I need :
a button with a background image
an image displayed on top of the button which is loaded from internet (a card , there is a lot of different and news cards are added daily, in the screnshot it s "MIDI PASS" )
a text localised on the button , so I cant use Imagebutton class.

It is not quite clear what you want to achieve, but the following may be helpful for you:
Use an ImageButton
Set the Image as the background of the button either in XML (using android:background) or in code (using setBackgroundResource)
Update:
Looking at your updated requirements, it would be better to use a custom component to achieve what you want.

Your question is somewhat unclear but from what i understood, following may work for you:
<ImageButton android:id="#+id/imgButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/bg_image"
android:src="#drawable/top_image"/>
Hope it will be helpful.
UPDATE:
If Your background is common, then you can set the bitmap using following code:
((ImageButton)findViewById(R.id.imgButton)).setImageBitmap(bmp);
Here, you will need to get the bitmap of the card image in bmp variable.

You can also use an ImageView and implement the onClickListener.

Yes it is possible.
Use an ImageButton then....
set your android:src="#drawable/foreground Image"
set your android:background="#drawable/background Image"
So if you wanted a an apple for the background image and a 3-d word "apple" for your foreground image.

You could try something like this:
First, you create a selector for the button in the res/drawable/ folder (let's call it selector_button.xml):
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:drawable="#drawable/image_resource_for_button_pressed"
android:state_pressed="true" />
<item android:drawable="#drawable/image_resource_for_button_pressed"
android:state_focused="true" />
<item android:drawable="#drawable/image_resource_for_button_normal" />
</selector>
Here you can define as and android:drawable not just #drawable's, but #color's or #layout's, too. If you want a more complex layout, you should define one with the background image of the button and another image on top of it using a RelativeLayout for example.
In order to do this, you have to have image_resource_for_button_pressed.png (for pressed and focused state) and image_resource_for_button_normal.png (for normal state) in your res/drawable/ folder.
After that, you create a button, like this:
<Button
android:id="#+id/aButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/selector_button"
android:text="Hardcoded string" />
This approach helps you maintain code readability, since you just extracted the changing of the image resource into an .xml file.

How to display the image inside the android widget background?

I have a widget layout xml which sets the src to the delivered android widget 4x1 frame image.Here is the widget layout code.
<?xml version="1.0" encoding="utf-8" ?>
<AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/tuwidget" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView android:id="#+id/tuwidget_img_btn"
android:src="#drawable/widgetinitial"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</AbsoluteLayout>
#drawable/widgetinitial holds the widgetinitial.png image example 4x1 at developer.android.com (AppWidget design guidelines).(4x1_Widget_Frame_Portrait.psd) What I am trying to do is display an image inside the delivered frame instead what happens is the frame image goes away and only the image I am trying to display shows up. How can I display the image inside the bounding box or the background?
Any help is much appreciated.
Another question - I think I saw in a couple of forums AbsoluteLayout is a deprecated feature for Android 2.1 and above. Is that correct? and does using AbsoluteLayout throws any force close or other exceptions?

AbsoluteLayout is deprecated. It doesn't throw any exceptions, but its generally a bad idea to use it because it is really hard to design a layout that will work on all screen sizes. There is generally a better way to do it using a different layout.
In your case, I don't follow exactly, but it sounds like you want to layer two widgets on top of each other? An image with a frame? To do so, I'd use a FrameLayout. This is designed for having multiple layers of images.
Common layout objects is also a good guide to the basic layout types.

Take a look at the end of the page 2 of this pdf