如何為不同的布局重用點擊監聽器

我的應用包含針對不同設備型別的 2 種不同布局。我希望執行不同的操作，例如第 1、第 2 和第 3 項導航到不同的螢屏，第 4 項顯示 a Toast，第 5 項啟動電子郵件撰寫器意圖等。有沒有辦法找出陣列的哪個索引是單擊并使這些單擊事件可重用，而不是兩次創建相同的單擊事件？

strings.xml 中的陣列

<string-array name="array_main">
    <item>@string/breads</item>
    <item>@string/cakes</item>
    <item>@string/condiments</item>
    <item>@string/desserts</item>
    <item>@string/snacks</item>
    <item>@string/contact us</item>
</string-array>

MainActivity.kt

class ActivityMain : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MyAppTheme {
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    HomeScreen(navController = rememberNavController())
                }
            }
        }
    }

    @Composable
    fun ComposeNavigation() {
        val navController = rememberNavController()
        NavHost(
            navController = navController,
            startDestination = "home_screen"
        ) {
            composable("home_screen") {
                HomeScreen(navController = navController)
            }
            composable("second_screen") {
                SecondScreen(navController = navController)
            }
            composable("third_screen") {
                ThirdScreen(navController = navController)
            }
        }
    }

    @Composable
    fun HomeScreen(navController: NavController) {
        val windowInfo = rememberWindowInfo()

        if (windowInfo.screenWidthInfo is WindowInfo.WindowType.Compact) {
            Scaffold(
                topBar = {...},
                content = {
                    MyLazyColumn(lazyItems = resources.getStringArray(R.array.array_main))
                },
            )
        } else {
            Scaffold(
                topBar = {...},
                content = {
                    MyLazyVerticalGrid(lazyItems = resources.getStringArray(R.array.array_main))
                },
            )
        }
    }
}

MyLazyColumn.kt

@Composable
fun MyLazyColumn(lazyItems: Array<String>) {
    val listState = rememberLazyListState()

    LazyColumn(
        state = listState,
    ) {
        items(lazyItems) { item ->
            Row(modifier = Modifier
                .fillMaxWidth()
                .clickable {
                }) {
                Text(
                    text = item,
                )
            }
        }
    }
}

MyLazyVerticalGrid.kt

fun MyLazyVerticalGrid(lazyItems: Array<String>) {
    val lazyGridState = rememberLazyGridState()

    LazyVerticalGrid(
        state = lazyGridState,
        columns = GridCells.Fixed(2),
        content = {
            items(lazyItems.size) { index ->
                OutlinedButton(
                    modifier = Modifier.padding(7.dp),
                    onClick = {/*TODO*/ }) {
                    Text(text = lazyItems[index]
                    )
                }
            }
        }
    )
}

uj5u.com熱心網友回復：

由于我們使用的是 Compose，因此我們可以利用 Kotlin。string-array我們可以創建一個包含所有選項的列舉類，而不是創建資源，如下所示：

enum class Choices(@StringRes val textResId: Int) {
    Breads(R.string.breads),
    Cakes(R.string.cakes),
    Condiments(R.string.condiments),
    Desserts(R.string.desserts),
    Snacks(R.string.snacks),
    ContactUs(R.string.contact_us),
}

然后，我們可以像這樣設定你的LazyColumn和LazyGrid：

@Composable
fun MyLazyColumn(
    lazyItems : Array<Choice>,
    onClickItem: (Choice) -> Unit
) {
    //...
        items(lazyItems) { choice ->
           //...
           Text(text = stringResource(choice.textResId))
           Button(
               //...
               onClick = { onClickItem(choice) }
           )
           //...
        }
    //...
}

@Composable
fun MyLazyGrid(
    lazyItems : Array<Choice>,
    onClickItem: (Choice) -> Unit
) {
    // ...
        items(lazyItems) { choice ->
           Text(text = stringResource(choice.textResId))
           Button(
               onClick = { onClickItem(choice) }
           )
        }
    // ...
}

要重用ClickListener，我們可以創建一個 lambda 物件并重用它：

@Composable
fun HomeScreen(/* ... */) {

    val listener: (Choice) -> Unit = { choice ->
        when(choice) {
            Breads -> {}
            Cakes -> {}
            Condiments -> {}
            Desserts -> {}
            Snacks -> {}
            ContactUs -> {}
        }
    }

    MyLazyGrid(
       lazyItems = arrayOf(
          /* Choice items you'd add to you list */
       ),
       onClickItem = listener
    )
    MyLazyColumn(
       lazyItems = arrayOf(
          /* Choice items you'd add to you list */
       ),
       onClickItem = listener
    )
}

uj5u.com熱心網友回復：

只需將您的點擊代碼塊存盤為變數。

val firstItemClicker = { /* Add Actions Here */ }
val secondItemClicker = { /* and So on */ }

像這樣使用它

FirstItem(
 Modifier.clickable { firstItemClicker() }
)

或者，

Button(
 onclick = { firstItemClicker() }
){
 Text("Click Recyler")
}

標籤：安卓 科特林 安卓布局 安卓意图 android-jetpack-compose

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