Why doesn’t my image appear when running the app?

Question

I have the following xml code in Android Studio:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
          xmlns:app = "http://schemas.android.com/apk/res-auto"
          xmlns:tools = "http://schemas.android.com/tools"
          android:layout_width = "match_parent"
          android:layout_height = "match_parent"
          android:orientation = "vertical"
          android:weightSum = "1">

<ImageView
    app:srcCompat = "@mipmap/logon_img"
    android:id = "@+id/imageView"
    android:layout_gravity = "center_horizontal"
    android:contentDescription="@string/app_name"
    android:layout_width = "match_parent"
    android:layout_weight = "0.38"
    android:layout_height = "100dp"/>

<TextView
    android:id = "@+id/login"
    android:layout_gravity = "center_horizontal"
    android:textSize = "30sp"
    android:textAlignment = "center"
    android:textStyle = "normal|bold"
    android:textColor = "@color/Red"
    android:text = "@string/typeUserName"
    android:layout_weight = "0.00"
    android:layout_width = "350dp"
    android:layout_height = "wrap_content"/>

<EditText
    android:layout_height = "wrap_content"
    android:inputType = "textPersonName"
    android:ems = "10"
    android:id = "@+id/account"
    android:layout_gravity = "center_horizontal"
    android:textAlignment = "center"
    android:textSize = "20sp"
    android:layout_width = "300dp"
    tools:ignore = "LabelFor"/>

<TextView
    android:text = "@string/password"
    android:layout_width = "350dp"
    android:layout_height = "wrap_content"
    android:id = "@+id/textView2"
    android:layout_weight = "0.00"
    android:layout_gravity = "center_horizontal"
    android:textSize = "30sp"
    android:textAlignment = "center"
    android:textStyle = "normal|bold"
    android:textColor = "@color/Red"/>

<EditText
    android:layout_width = "300dp"
    android:layout_height = "wrap_content"
    android:inputType = "textPassword"
    android:ems = "10"
    android:id = "@+id/password"
    android:layout_gravity = "center_horizontal"
    android:textAlignment = "center"
    android:textSize = "20sp"
    tools:ignore = "LabelFor"/>

<Button
    android:text = "@android:string/ok"
    android:layout_height = "wrap_content"
    android:id = "@+id/button"
    android:layout_gravity = "center_horizontal"
    android:layout_width = "200dp"
    android:textSize = "20sp"
    />

</LinearLayout>

The component in question is Imageview, it simply does not appear in the emulator or on my phone, however, there is an empty space reserved for it on the screen. I searched the problem several times and in the vast majority of them was the huge size of the image, which is not my case because its size is 256x256. Follow a screenshot of the emulator and layout.

minSdkVersion 19
targetSdkVersion 25
com.android.support:appcompat-v7:25.0.0

Answer 1

I tested its layout and it was correctly presented.

The only thing I see that might be creating the problem is the use of the attribute app:srcCompat.
Despite the main reason for the existence of the attribute app:srcCompat enable the use of Vectordrawable in older versions of Android, it also (should) supports(r) the use of bitmaps.

So replace

app:srcCompat = "@mipmap/logon_img"

for

android:src = "@mipmap/logon_img"

If @mipmap/logon_img is a Vectordrawable see this reply

Answer 2

I’ve had some problems with images on android, many of them disappeared with the use of a library called Picasso.

This situation occurs because the image is not "fitting" within the layout size, in the lines:

android:layout_width = "match_parent"
android:layout_weight = "0.38"
android:layout_height = "100dp"

You can try to "fit" the image by decreasing its resolution, using tools such as resize (free tool and online). Or change the size in the layout itself.

But I guide you to try to implement the Picasso. To do this simply insert into the dependencies of the build.gradle:

dependencies {
.
.
.
compile 'com.squareup.picasso:picasso:2.5.2
}

Remove the line app:srcCompat = "@mipmap/logon_img" of xml and in his Activity within the onCreate, insert the line:

Picasso.with(getApplication()).load(R.mipmap.logo_img).resize(256, 256).centerCrop().into(imageView);

If it doesn’t work, the image may be much larger than you would like or not appear, inside the .resize(x,y) you can put a ratio to fit your image in the layout.