Develop Reference

why my first app doesn't show up on my phone?

I'm creating my first hello word apps, the first one shows just a hello word test and it worked on my phone, but i put a picture in the second one and run it the phone shows: the app has stopped ; my app looks on the xml design exactly how i wanted it !! (my phone has android 7 and i made the app with android 4)
the picture that i tried to show has a 3096x4128 resolution, but when i tried other picture that has less resolution has worked , i don't know if it's just a coincidence !i tried to change the app's android but same problem!
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="centerCrop"
android:src="#drawable/hugo" />
<TextView
android:text="What a Picture!"
android:textSize="36sp"
android:fontFamily="sans-serif-light"
android:textColor="#android:color/white"
android:padding="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:text="By AYMEN "
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="20dp"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:fontFamily="sans-serif-light"
android:textSize="36sp" />

I think you are getting OutOfMemory Error. To avoid this you can use the Picasso or Glide libraries
implementation 'com.squareup.picasso:picasso:2.71828'
In Picasso you can use the .fit() method to optimize the image and load it into your ImageView without losing the image quality.
Picasso
.with(context)
.load(UsageExampleListViewAdapter.eatFoodyImages[0])
.fit()
// call .centerInside() or .centerCrop() to avoid a stretched image
.into(imageViewFit);

you have to used image size is less than 2MB. This is the main reason to stop the app. So try to resize it & then used it in ImageView

Card view not working below Lollipop version

I am using card view but the elevation and card view properties are not working below version 5.0.
I tried to use card_view:cardUseCompatPadding="true" by searching some SO posts but this also did not work.
It should look like this
And it looks like this on 4.2.2
Here is layout:
<android.support.v7.widget.CardView
xmlns:app="http://schemas.android.com/tools"
android:id="#+id/card_view"
app:cardUseCompatPadding="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="05dp"
android:layout_marginTop="05dp"
card_view:cardElevation="12dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="60dp"
android:background="#color/bg">
<View
android:layout_width="3dp"
android:layout_height="match_parent"
android:background="#color/cardLineColor"></View>
<LinearLayout
android:id="#+id/linearLayout6"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginEnd="10dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginStart="10dp"
android:orientation="vertical">
<TextView
android:id="#+id/txt_id"
android:layout_width="103dp"
android:layout_height="wrap_content"
android:text="ID"
android:textColor="#color/white" />
<TextView
android:id="#+id/txt_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="05dp"
android:text="23/3/2015"
android:textColor="#color/textColor"
android:textSize="10sp" />
</LinearLayout>
<TextView
android:id="#+id/txt_trans_type"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/linearLayout6"
android:layout_centerHorizontal="true"
android:text="sent money"
android:textColor="#color/white"
android:textStyle="bold" />
<LinearLayout
android:id="#+id/linearLayout8"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/linearLayout6"
android:layout_marginEnd="10dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginStart="10dp"
android:layout_toEndOf="#+id/txt_trans_type"
android:layout_toRightOf="#+id/txt_trans_type"
android:orientation="vertical">
<TextView
android:id="#+id/txt_balance"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="end"
android:text="$3214"
android:textAlignment="viewEnd"
android:textColor="#color/white"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="end"
android:layout_marginTop="05dp"
android:text="#string/balance"
android:textAlignment="viewEnd"
android:textColor="#color/white"
android:textSize="10sp" />
</LinearLayout>
</RelativeLayout>
</android.support.v7.widget.CardView>
Edit: I created 9 patch file like this
But this is giving this error:
Error:Some file crunching failed, see logs for details
Error:Execution failed for task ':app:mergeDebugResources'.
> Error: Some file crunching failed, see logs for details
May be its height width is much? I tried with small height width but then it leaves some gap. How can I match it to all devices?

Use app:cardElevation="12dp"
instead of card_view:cardElevation="12dp"
Hope it helps.

Sadly, elevation, as you mentioned it, is not available for API 19 and below.
The solution I chose for my similar issue is to replace my cardviews by regular layouts and use 9-patch images as background to generate the shadows. It has the advantage to be very modulable, plus, unlike the elevation property, you can have more customization like shadow colors if you don't want a simple black shadow.
The only problem is that you have to design the image yourself and add it to the project. But fear not, there is some handy generators like this one that can generate it for you. Just make sure that you set a minimum size that is less than your layout to be sure it fits without deforming it. I usually generates a 10*10 pixels wide image, and shadows won't be deformed even when applied to a much larger view.
When you got your image (name should look like myimage.9.png), you simply add it to your drawables, without removing the .9.png extension, and then set it as a regular background drawable to your layout, via xml or code. And you're done !
EDIT : Did not notice you also have lighting on the top of the cardview.. What you can try if you have something like Photoshop, is to create yourself the 9-patch, by applying drop shadows for the dark one, then creating a second layer to add another drop shadow but this time set to white and with the appropriate angle to display it above. Then you save it as png and use the 9-patch generator to convert it to a .9.png image.
See the 9-patch documentation here. If you're using Android Studio, there is also a built-in generator for 9-patches.
Sadly, user interface was kinda limited for advanced displaying like shadows before Material Design stepped in with Android 5. Maybe you can add your cardviews programmatically, so you can do something like this
if (android.os.Build.VERSION.SDK_INT <= android.os.Build.VERSION_CODES.LOLLIPOP){
//Add regular layout to your views with 9 patch
} else{
//Add cardview to get desired effect
}
That way most of your users will have your desired cardviews, but it can quickly increase the amount of code you'll need if you need your element to be clickable/draggable/etc.

How do I make the foreground attribute for a button work below API 23?

I have two Buttons nested in a LinearLayout. Between these Buttons are two TextViews. In the Xml, I have set the foreground to an image for each of these Buttons.
It runs fine on my device for Api 23. But on other devices below Api 23, the foreground image does not display and instead results in a default white solid color. Is there any way to make these images show using foreground below Api 23?
We have tried FrameLayout but it does not do what we want it to do. Would ImageButtons be a better way to solve this issue?
One of the core functions of our app is that every time a user taps a Button, the size increases and the image stretches accordingly. This is done dynamically in code. If I were to use ImageButtons, I would need to set the layout parameters every time for height and width, rather than one line of code that sets the height.
Any tips would be appreciated!
EDIT: Code I am working with -
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="11"
android:background="#android:color/black">
<Button
android:layout_weight="5"
android:id="#+id/firstP"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:foreground="#drawable/icebutton"
android:scaleX="1"
android:scaleY="1"/>
<TextView
android:layout_weight="0.5"
android:id="#+id/firstPlayer"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:rotation="180"
android:textColor="#android:color/white"
android:background="#android:color/transparent"/>
<TextView
android:layout_weight="0.5"
android:id="#+id/secondPlayer"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="#android:color/white"
android:background="#android:color/transparent"/>
<Button
android:layout_weight="5"
android:id="#+id/secondP"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:foreground="#drawable/firebutton"
android:scaleX="1"
android:scaleY="1"/>
</LinearLayout>

We found out that there were two issues causing the images to not be shown.
1. The size of the image file was too big, creating an outOfMemory error which in turn resulted in the buttons not displaying the images.
2. The foreground attribute does not work for API 22 and below.
Steps to solving these issues:
1. We reduced the size of the image files.
2. We replaced Button with ImageButton
3. In the XML file we removed the foreground attribute, added a black background, and added the image via the src attribute. The following is a snippet.
<ImageButton
android:layout_weight="5"
android:id="#+id/firstP"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:src="#drawable/icebutton"
android:scaleType="fitXY"
android:background="#android:color/black"/>
We then had to change our code to dynamically adjust the height of the buttons to match the new image buttons with the help of this link by setting the LayoutParams:
how to change size of button dynamic in android
Now everything works perfectly!

How to Show Image View in android?

I am sorry I am very beginner in java/android, maybe this question is too bad.
I want to display my icon in splash screen, but if I use ic_launcher it's size is too small. (192x192)
When I generate ic_launcher from new image asset it generates an image with size 512x512 in "app\src\main\ic_launcher-web.png"
Can I display that image?
I think I can change #mipmap/ic_launcher to some path/image location. So, I don't need to copy my image to drawable/mipmap directory.
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:src="#mipmap/ic_launcher" />
I have been looking for it and did not find it.
Thanks for help

Save your original image in res/drawable/youimage.png. Then call it from
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:src="#drawable/yourimage.png" />

Image view doesn't display image if screen is not rotated and an other image view has been updated

Issue
I've got an issue with 2 ImageViews on Android.
The first displays a large image. It is inside a RelativeLayout, and is a custom ImageView (com.ortiz.touch). It was displaying well until now.
The second is also inside the RelativeLayout but is a "normal" ImageView. It shows bluetooth state. Displaying it doesn't cause any issue.
However, when I put code that changes the src of the bluetooth indicator programatically, the first image is not displayed anymore ....
Is the problem coming from the custom view not doing its job right ? Am I missing something ?
Code
If I'm not doing this kind of stuff :
bluetoothState.setImageResource(R.drawable.bluetooth_enabled192);
The image is displayed correctly.
Here's the layout I use :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#1b1b1b"
android:theme="#style/Theme.AppCompat.Light.NoActionBar.FullScreen">
<com.ortiz.touch.TouchImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/imageView"
android:layout_gravity="center"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_above="#+id/textView" />
<TextView
android:layout_width="fill_parent"
android:layout_height="32dp"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="#string/emptyDisplayText"
android:layout_gravity="center_horizontal|bottom"
android:gravity="center_vertical|center_horizontal"
android:textAllCaps="true"
android:elegantTextHeight="false"
android:ellipsize="end"
android:maxLines="1"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:textSize="15sp"
android:textColor="#f3f3f3"
android:id="#+id/textView"
android:background="#drawable/rounded_rect"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
android:layout_margin="10dp" />
<ImageView
android:layout_width="52dp"
android:layout_height="52dp"
android:id="#+id/bluetooth_state"
android:scaleType="centerCrop"
android:layout_alignParentTop="true"
android:layout_alignRight="#+id/textView"
android:layout_alignEnd="#+id/textView"
android:layout_gravity="top|right"
android:layout_margin="10dp"/>
</RelativeLayout>
Desired Result
What I get is the same screen without the central image (the text and bluetooth indication are displayed correctly)
 NB
I'm starting to get quite depressed on that issue. I just want to display 2 images. Thank you.
Edit
I've not mentioned it, but the main image is loaded in background, using an AsyncTask. I've tried to add some View.invalidate() (on top level layout, on image, on bluetooth indication) but it hasn't solved the problem.
In addition to the image appearing on rotation, it also appears when I try to pinch the non-existant image. And trying to reset the zoom (hacky) programatically doesn't work either.

Okay I've found the error.
As I said, I have a AsyncTask (BitmapWorkerTask) that I call to load a Bitmap into an ImageView in background.
It's called like this :
new BitmapWorkerTask(imageView, getApplicationContext()).execute(filename);
Changing getApplicationContext() to MainActivity.this or getContext() solves the issue :/ (However, I still find it's quite magic how it worked fine for so long even if application context != activity context !)