【Jetpack Compose 筆記】TextField 與 Toast 烤土司般的短訊息

Toast 訊息就像是很久以前的烤土司機一樣，會跳出簡短的文字訊息，以下示範如何使用。

@OptIn(ExperimentalComposeUiApi::class)
@Composable
fun MyApp() {
    val context = LocalContext.current
    val message = remember { mutableStateOf("") }
    val keyboardController = LocalSoftwareKeyboardController.current
    val focusManager = LocalFocusManager.current

    Column(modifier = Modifier.fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center) {
        TextField(
            value = message.value,
            onValueChange = {
                message.value = it
            },
            label = {Text("輸入你想烤的吐司訊息？")},
            maxLines = 1,
            keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
            keyboardActions = KeyboardActions(
                onDone = {
                    keyboardController?.hide()
                    focusManager.clearFocus()
                }
            )
        )

        Button(
            onClick = {
                if(message.value.isNotEmpty())
                    Toast.makeText(context, message.value, Toast.LENGTH_SHORT).show() }
        ) {
            Text(text = "點我蹦一則訊息")
        }
    }

    
}

簡單說明：
keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done): 這是用於設置鍵盤選項的參數，imeAction = ImeAction.Done 表示軟鍵盤的 Enter 鍵顯示 “Done(完成)”或”勾勾”。

keyboardActions = KeyboardActions(onDone = { ... }): 當按下軟鍵盤的 Done(完成) 按鈕時，會執行以下。首先，keyboardController?.hide()，表示要隱藏軟鍵。再來， focusManager.clearFocus() 則會使輸入框失去焦點，變成非被選取的狀態。

下面是展示畫面。