A button which allows an image to be shown in Android Studio - java

I am building my application using Android Studio, this app can upload an image from raspberry to my emulator. It works fine. What I want to do now is uploading this image and showing it directly to the user without searching it in the gallery. I thought about creating another class and setting this image as a background image in my xml file, but this is too much like I have to create another class every time I want to upload an image from my raspberry.
Can someone help me please. Thank you

If I'm understanding your question correctly, you'd like to load an image from the Android filesystem into your app and display it to the user.
Drawable, Android's generalized image class, allows you to load from file via Drawable#createFromPath.
This SO question suggests Drawable#createFromPath doesn't work on paths beginning with file://, so depending on your use case you may want to precede that with Uri#parse/Uri#getPath.
Once you have a Drawable, you can display it in one of two ways: put an ImageView in your app and call its setImageDrawable method, or set the Drawable as your background image via View#setBackground (note that setBackground was only added in API 16 - in prior versions, you should call View#setBackgroundDrawable).
Putting all of this together, we end up with the following (untested):
private void loadImage(String imagePath) {
Uri imageUri;
String fullImagePath;
Drawable image;
ImageView imageDisplay;
imageUri = Uri.parse(imagePath);
fullImagePath = imageUri.getPath();
image = Drawable.createFromPath(fullImagePath);
imageDisplay = (ImageView) findViewById(R.id.imageDisplay);
/*if image is null after Drawable.createFromPath, this will simply
clear the ImageView's background */
imageDisplay.setImageDrawable(image);
/*if you want the image in the background instead of the foreground,
comment the line above and uncomment this bit instead */
//imageDisplay.setBackground(image);
}
You should be able to modify this to work with any View just by replacing imageDisplay's declared type with the appropriate View type and changing the cast on findViewById. Just make sure you're calling setBackground, not setImageDrawable, for a non-ImageView View.

Related

How to change a photo?

I am trying to change photos in android studio by clicking on my button.
When I put code for changing the photo in my MainActivity.java I keep getting this type of error messages and it says :
Cannot resolve symbol "image"
image.setImageResource(R.drawable.xxx);
I am watching Udemy course for android development and I have done everything same like the professor on that video.
I have tried to restart android studio.
I have tried to make new project.
I have tried to clear invalidate caches and restart.
public void changeImage(View view)
{
ImageView bitcoin = findViewById(R.id.bitcoin);
image.setImageResource(R.drawable.xxx);
}
I hope there is actual error with android studio,because code is clone of the video that I am watching.
You are binding your layout's ImageView in Java file with bitcoin variable and you are trying to set an image on an unknown variable 'image'(maybe it's not defined in the class). So you have to set as below.
ImageView bitcoin = findViewById(R.id.bitcoin);
bitcoin.setImageResource(R.drawable.xxx);
Set Your Code Like this
ImageView image = findViewById(R.id.bitcoin);
image.setImageResource(R.drawable.xxx);
change your this line
image.setImageResource(R.drawable.xxx)
to this one:
bitcoin.setImageResource(R.drawable.xxx)

Bitmap and proper saving location

Hi everybody I've got the following problem with an adroid app: I want to read an image saved and perform some operations on it.
(I do not need to use this image to draw something on screen, I just have to check the color of some pixels)
I'm using the following code:
Bitmap bitmap = BitmapFactory.decodeFile("drawable-v24/ean13.bmp");
The fact is that the BitmapFactory returns null as a FileNotFoundException is thrown. (by now the file is saved inside res folder)
I don't really understand where I should put the image and how to give the path to the BitmapFactory to be able to get it properly.
(I guess the problem is due to the fact that the image actually is stored on my pc and not on the Android device but I can't understand how should I proceed)
Thank you in advance for the help! :)
If you are accessing image from resource drawable of mipmap. You should use BitmapFactory.decodeResource to get Bitmap.
Bitmap bitmap=BitmapFactory.decodeResource(getResources(),R.mipmap.ic_launcher);
Or another overloaded version .
public static Bitmap decodeResource(Resources res, int id, Options opts)
where getResources() is method of Activity.

Most efficient way to load a lot of images from URL Android

I'm making this netflix style app in which images are loaded into different categories. Let's say Dog videos (has 15 images), Cat videos (15 images), etc... All the images are loaded from a URL, it kind of takes a while for all to load. I was wondering if there was anything I could do to speed up the process? Or maybe show an empty container then fill it as the images load (that would be cool).
This is what I have done:
I have multiple async calls in one Activity, (1 async call per category)
JSONTask1 dogTask = new JSONTask1();
JSONTask2 catTask = new JSONTask2();
JSONTask3 pigTask = new JSONTask3();
JSONTask4 horseTask = new JSONTask4();
dogTask.execute("");
catTask.execute("");
pigTask.execute("");
horseTask.execute("");
I have all of those in a row in my actual code. Thanks.
I would use the "proxy pattern". Basically, you need to create a class that contains the minimal informations required for the display. In which, you have a preview image.
When ever you load everything you start by showing the preview content, ie : a loading gif for everypicture with the title of the movie or whatever. and basically the proxy would have a "loadImage" method that would make an ajax call or async call and the photos would load one by one. Plus, to make the loading easier, make sure the photos are not oversized.
You can see Picasso answers , in picasso i suggest you this way :
Picasso.with(getApplicationContext()).load("your url").placeholder(R.drawable.your_place_holder).error(R.drawable.showing_when_error_occured)
.into(imageView, new Callback() {
#Override
public void onSuccess() {
}
#Override
public void onError() {
}
});
Also another suggestion from me : convert your thumb images to base64 format in backend, then firstly retrieve your thumbs and show them. Then start an async task and change images when successfull.
Like whatsapp. In whatsapp you have thumb images they have so low resolution and super fast. When you click image if you have internet connection they load actual thumb images, and click again they load larger image.
Picasso website :http://square.github.io/picasso/
Load them asynchronously with Picasso, you can even show a placeholder image until the real one is loaded

Is it possible to get a higher resolution from getDrawingCache?

I am using SubsamplingScaleImageView by Dave Morrissey (https://github.com/davemorrissey/subsampling-scale-image-view) to allow users to crop and pan a photo with gestures.
I modified the library to add a tint and a logo to the photo. Now I need to upload the photo to the server. In order to do that I need to somehow extract the photo from the SubsamplingScaleImageView.
I added the following method to the SubsamplingScaleImageView class:
/**
* Capture a photo of the image view
*/
public Bitmap getOutput() {
buildDrawingCache();
Bitmap b1 = getDrawingCache();
Bitmap b = b1.copy(Config.ARGB_8888, true);
destroyDrawingCache();
return b;
}
I am using this method to get the file, resize it to a specific resolution (800x800), and save it to my app's folder.
The problem I noticed is that the extracted photo from the drawing cache depends on the resolution of the device. For example, on my Full HD device I get 1080x1080 photo, which is enough, but on some lower res devices I get resolutions like 480x480 and that is not enough since the image needs to be bigger than that, so the photo gets blurry when I resize it to 800x800.
Is there a way to get the same resolution photo from that image view on all devices?

Binding Image in Javafx

In my Javafx application, I have a gallery. What I want to do is that, as soon as an Image is available available in a folder, it should show that Image on the screen.
Is there anyway to bind an Image in an IamgeView. Just like any other String or Property? I can have something called ImageProperty and it will be binded to the Image. So if I change the image in the ImageProperty, it will update the UI
Done. ImageView has an Object Property to which an ObjectProperty can be binded.
i.e.
private ObjectProperty<javafx.scene.image.Image> imageProperty = new SimpleObjectProperty<>();
#FXML
private ImageView imageDisplay;
Bindings.bindBidirectional(this.imageDisplay.imageProperty(), GlobalModel.getInstance().getProject().getImageProperty());

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