Java.lang.nullpointerexception: attempt to invoke virtual method on a null object reference

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null

exceptions

Kotlin

I'm writing an app in Kotlin, which displays 2D object on user's phone. When I execute my code, I get Java.lang.nullpointerexceptionRun. Sadly, I don't know how to fix this issue. Run output:

E/com.a3dmodelap: Invalid ID 0x00000000.
E/AndroidRuntime: FATAL EXCEPTION: GLThread 633
    Process: com.a3dmodelapp, PID: 7503
    java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.Bitmap.getWidth()' on a null object reference
        at com.a3dmodelapp.Texture.load(Texture.kt:80)
        at com.a3dmodelapp.Stage$MyRenderer.onSurfaceCreated(Stage.kt:91)
        at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1541)
        at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1272)

So basically it fails at this line (Texture.kt:80):

Quote:

width = bmp.getWidth()

I'm new to Kotin and already spent hours trying to fix it. Would greatly appreciate the help. Here's the code in Texture class:

...
private var width : Int = 0
private var height : Int = 0
var resourceId = 0
...
constructor(resourceId: Int, mipmaps: Boolean)
{
   this.resourceId = resourceId
   this.textureId = -1
   this.mipmaps = mipmaps
}
constructor(resourceId: Int) {
   this(resourceId, false)
   Texture(resourceId, false)
}
...
fun getWidth(): Int 
{
   return width
}

fun getHeight(): Int
{
   return height
}
...
fun load(context: Context)
{
   val opts = BitmapFactory.Options()
   opts.inScaled = false
   val bmp = BitmapFactory.decodeResource(context.getResources(), resourceId, opts)
   width = bmp.getWidth()
   height = bmp.getHeight()
...
}

UPDATE: It seems that resourceId is the problem. bmp variable is null, because of resourceId being 0. Followed my code step by step and I can't figure out where the problem may be. Right down below I provide more in depth walktrough of resourceId variable.
In Stage class I have a call to the constructor:

tex = Texture(getResources().getIdentifier(img, "drawable", context?.getPackageName()))

After checking, it is basically the same as this:

tex = Texture(2131165330)

So that means it's calling the second constructor in Texture class:

constructor(resourceId: Int) 
{
   Texture(resourceId, false)
}

And then the first one:

constructor(resourceId: Int, mipmaps: Boolean) 
{
   this.resourceId = resourceId
   this.textureId = -1
   this.mipmaps = mipmaps
    }

resourceId shouldn't be equal to 0, but to 2131165330 (I've checked and it is being set in the first constructor). I don't know why it's equal to 0

UPDATE 2
Below I provide you Stage class (the most relevant to me lines of code have been bolded):

class Stage(context: Context?, attrs: AttributeSet?) : GLSurfaceView(context, attrs) {

    private var w = 0.0F
    private var h = 0.0F
    private var screenHeight = 0
    private var screenWidth = 0
    private lateinit var vertexBuffer: FloatBuffer
    private lateinit var tex: Texture
    private var img = ""
    private var xPos = 0.0F
    private var yPos = 0.0F
    private var r = 0.0F

    init {
        setEGLConfigChooser(8, 8, 8, 8, 0, 0)
        setRenderer(MyRenderer())

        val vertices = floatArrayOf(
            -0.5f, -0.5f, 0.0f,
            0.5f, -0.5f, 0.0f,
            -0.5f, 0.5f, 0.0f,
            0.5f, 0.5f, 0.0f,
        )

        val vbb: ByteBuffer = ByteBuffer.allocateDirect(vertices.size * 4)
        vbb.order(ByteOrder.nativeOrder())
        vertexBuffer = vbb.asFloatBuffer()
        vertexBuffer.put(vertices)
        vertexBuffer.position(0)

        img = "football"
        tex = Texture(getResources().getIdentifier(img, "drawable", context?.getPackageName()))
    }

    private inner class MyRenderer : Renderer {
        override fun onDrawFrame(gl: GL10) {
            gl.glClear(GLES10.GL_COLOR_BUFFER_BIT)
            tex.prepare(gl, GL10.GL_CLAMP_TO_EDGE)
            gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer)
            tex.draw(gl, xPos, yPos, tex.getWidth()*r, tex.getHeight()*r, 0f)
        }
        override fun onSurfaceChanged(gl: GL10, width: Int, height: Int) {
            gl.glClearColor(0f, 0f, 0f, 1.0f)
            if (width > height) {
                h = 600F
                w = width * h / height
            } else {
                w = 600F
                h = height * w / width
            }
            screenWidth = width
            screenHeight = height

            xPos = w/2
            yPos = h/2
            r= 1F

            gl.glViewport(0, 0, screenWidth, screenHeight)
            gl.glMatrixMode(GL10.GL_PROJECTION)
            gl.glLoadIdentity()
            gl.glOrthof(0f, w, h, 0f, -1f, 1f)
            gl.glMatrixMode(GL10.GL_MODELVIEW)
            gl.glLoadIdentity()
        }

        override fun onSurfaceCreated(gl: GL10?, p1: EGLConfig?) {
            // Set up alpha blending
            gl?.apply {
                glEnable(GL10.GL_ALPHA_TEST)
                glEnable(GL10.GL_BLEND)
                glBlendFunc(GL10.GL_ONE, GL10.GL_ONE_MINUS_SRC_ALPHA)
                // We are in 2D, so no need depth
                glDisable(GL10.GL_DEPTH_TEST)
                // Enable vertex arrays (we'll use them to draw primitives).
                glEnableClientState(GL10.GL_VERTEX_ARRAY)

                gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY)
                tex.load(getContext())
            }
        }
    }
}

UPDATE 3
I think I've found where the issue is, but I don't know how to solve it. Right here I'm making a call to the second constructor:

tex = Texture(getResources().getIdentifier(img, "drawable", context?.getPackageName()))

In the second constructor, I call the first one, but it doesn't make any sense, because it doesn't save values back to the Stage class. What I want to do is create something like this:

constructor(resourceId: Int) 
{
   this(resourceId, false)
}

In Java it would work perfectly fine, but here in Kotlin it doesn't. This is the only line that needs work, because if I make a call like the one provided below everything works just fine:

tex = Texture(getResources().getIdentifier(img, "drawable", context?.getPackageName()), false)

What I have tried:

I've spent hours trying to solve this with no success