ComposePanel. Focus moves to child after focusing/unfocusing the main window

[igordmn]

Compose 1.6.20-dev1663

1. Run

import androidx.compose.foundation.border
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.padding
import androidx.compose.material.TextField
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.awt.ComposePanel
import androidx.compose.ui.focus.focusTarget
import androidx.compose.ui.focus.onFocusChanged
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp
import java.awt.Dimension
import javax.swing.JFrame
import javax.swing.SwingUtilities

fun main() = SwingUtilities.invokeLater {
    val panel = ComposePanel()
    panel.setContent {
        var isFocused by remember { mutableStateOf(false) }
        Box(Modifier
            .onFocusChanged { isFocused = it.isFocused }
            .focusTarget()
            .border(1.dp, if (isFocused) Color.Red else Color.Transparent)
            .padding(8.dp)
        ) {
            TextField("", {}, singleLine = true)
        }
    }

    val frame = JFrame()
    frame.contentPane.add(panel)
    frame.size = Dimension(500, 500)
    frame.isVisible = true
}

2. Focus the box
   
3. Deactivate/Activate the window
4. See that focus moved to the textfield
   

This happens, because Swing calls focusGained with FocusEvent.Cause.ACTIVATION when activating the main window, and Enter moves the focus to the child

Regression after JetBrains/compose-multiplatform-core#1352

[igordmn]

Will be fixed in integration branch

[m-sasha]

I guess the fix will be to focus the first focusable element instead of "Enter"?

[igordmn]

The fix will be to skip requesting focus if it is already in focus. It is the only way to behave when we activate/deactivate window.

[m-sasha]

I couldn't immediately find a way to check if something is already focused. When "nothing" is focused, the root node has the focus.

[okushnikov]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.