Android kotlin - Unresolved reference for setImageBitmap in fragment

Question

I just try to set a Bitmap inside an ImageView in fragment:

imageLeft.setImageBitmap(duelbildBitmap)

and get Unresolved reference for setImageBitmap

Why? It works in activity

Thanks in advance

Let me see, how you have included ImageView in layout, and what is import line you have in your kotlin class. Or just show full code related to this issue. — Khemraj Sharma, Oct 18 '18 at 05:45
It's kotlin, no probs doing it that way. If anything would be wrong with the variable then setImageBitmap wouldn't be Unresolved reference, the problem lies in the fact that it's inside fragment and I need workaround — , Oct 18 '18 at 05:46
In fragment, ids are not referred like activity. See https://stackoverflow.com/a/47708920/6891563 — Khemraj Sharma, Oct 18 '18 at 05:48
Ok it's this way: import com.amoflirt.amoflirt.R.id.imageLeft correct so? What are you suggesting? — , Oct 18 '18 at 05:49
`R.id.imageLeft` returns integer id, not ImageView object bro. So int value does not have `setImageBitmap` method. — Khemraj Sharma, Oct 18 '18 at 05:53
Either do findViewById() or do it like https://stackoverflow.com/a/47708920/6891563 — Khemraj Sharma, Oct 18 '18 at 05:54
I tried val picleft = findViewById(R.id.imageLeft) now and get unresolved reference for findViewById — , Oct 18 '18 at 05:57

score 3 · Accepted Answer · answered Oct 18 '18 at 06:03

You can not just use R.id.imageView, because that is integer id not the ImageView object. So it can not find setImageBitmap() method on Integer.

You have two ways

1: by using `findViewById()`

class GalleryFragment : Fragment() {
    private lateinit var viewOfLayout: View
    private lateinit var imageView: ImageView

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        viewOfLayout = inflater.inflate(R.layout.fragment, container, false)
        return viewOfLayout
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        imageView = view.findViewById(R.id.imageView)
        imageView.setImageBitmap(bitmap) // set bitmap anywhere
    }
}

2: by using `kotlinx.android.synthetic`

class GalleryFragment : Fragment() {
    private lateinit var viewOfLayout: View
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        viewOfLayout = inflater.inflate(R.layout.fragment, container, false)
        viewOfLayout.imageView.setImageBitmap(bitmap) // set bitmap anywhere
        return viewOfLayout
    }
}

If imageView is not imported automatically in this case, then import manually.

import kotlinx.android.synthetic.main.fragment.view.*

In second method you have to apply plugin apply plugin: 'kotlin-android-extensions' if not applied at the end of app level build.gradle file.

No it was example, make imageview object at class level and use it anywhere in your class. — Khemraj Sharma, Oct 18 '18 at 06:08
In second method, you can use `viewOfLayout.imageView.setImageBitmap()` anywhere in your class. — Khemraj Sharma, Oct 18 '18 at 06:09
In first method you can use `imageView.setImageBitmap` anywhere. — Khemraj Sharma, Oct 18 '18 at 06:10
This is the "JAVA way" to do it and I learned JAVA only like 1 hour before I puked and never touched it again — , Oct 18 '18 at 06:11
I suggest learn data binding of android, in that you can just use `binding.imageView`. And there are many other benefits of binding, like live reload of UI when data changed. — Khemraj Sharma, Oct 18 '18 at 06:11

Android kotlin - Unresolved reference for setImageBitmap in fragment

1 Answers1

1: by using findViewById()

2: by using kotlinx.android.synthetic

1: by using `findViewById()`

2: by using `kotlinx.android.synthetic`