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切片模板

本文档详细介绍了如何使用 Android Jetpack 中的模板构建器构造切片

定义切片模板

切片是使用 ListBuilder 构造的。利用 ListBuilder,您可以添加显示在列表中的不同类型的行。本部分介绍了每种行类型及其构造方式。

SliceAction

切片模板的最基本元素是 SliceActionSliceAction 包含一个标签以及一个 PendingIntent,它是以下某一项:

  • 图标按钮
  • 默认切换开关
  • 自定义切换开关(一个具有开启/关闭状态的可绘制对象)

SliceAction 由模板构建器使用,详见本部分余下篇幅。您可以为 SliceAction 定义一种图片模式,该模式决定了如何为操作呈现图片:

  • ICON_IMAGE:超小尺寸,可着色
  • SMALL_IMAGE:小尺寸,不可着色
  • LARGE_IMAGE:最大尺寸,不可着色

HeaderBuilder

在大多数情况下,您应使用 HeaderBuilder 为模板设置标头。标头可以支持以下几项:

  • 标题
  • 副标题
  • 摘要副标题
  • 主要操作

一些标头配置示例如下图所示。请注意,灰色框表示可能的图标和内边距位置:

在不同界面上呈现的标头

当需要切片时,显示界面会决定如何呈现切片。请注意,切片在不同托管界面上的呈现方式可能会略有不同。

采用较小的格式时,通常只会显示标头(如果存在)。如果您为标头指定了摘要,则会显示摘要文字,而不是副标题文字。

如果您尚未在模板中指定标头,则通常会显示添加到 ListBuilder 的第一行。

HeaderBuilder 示例 - 包含标头的简单列表切片

Kotlin

fun createSliceWithHeader(sliceUri: Uri) =
    list(context, sliceUri, ListBuilder.INFINITY) {
        setAccentColor(0xff0F9D) // Specify color for tinting icons
        header {
            title = "Get a ride"
            subtitle = "Ride in 4 min"
            summary = "Work in 1 hour 45 min | Home in 12 min"
        }
        row {
            title = "Home"
            subtitle = "12 miles | 12 min | $9.00"
            addEndItem(
                IconCompat.createWithResource(context, R.drawable.ic_home),
                ListBuilder.ICON_IMAGE
            )
        }
    }

Java

public Slice createSliceWithHeader(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }

    // Construct the parent.
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY)
            .setAccentColor(0xff0F9D58) // Specify color for tinting icons.
            .setHeader( // Create the header and add to slice.
                    new HeaderBuilder()
                            .setTitle("Get a ride")
                            .setSubtitle("Ride in 4 min.")
                            .setSummary("Work in 1 hour 45 min | Home in 12 min.")
            ).addRow(new RowBuilder() // Add a row.
                    .setPrimaryAction(
                            createActivityAction()) // A slice always needs a SliceAction.
                    .setTitle("Home")
                    .setSubtitle("12 miles | 12 min | $9.00")
                    .addEndItem(IconCompat.createWithResource(getContext(), R.drawable.ic_home),
                            SliceHints.ICON_IMAGE)
            ); // Add more rows if needed...
    return listBuilder.build();
}

标头中的 SliceAction

切片标头也可以显示 SliceAction:

Kotlin

fun createSliceWithActionInHeader(sliceUri: Uri): Slice {
    // Construct our slice actions.
    val noteAction = SliceAction.create(
        takeNoteIntent,
        IconCompat.createWithResource(context, R.drawable.ic_pencil),
        ICON_IMAGE,
        "Take note"
    )

    val voiceNoteAction = SliceAction.create(
        voiceNoteIntent,
        IconCompat.createWithResource(context, R.drawable.ic_mic),
        ICON_IMAGE,
        "Take voice note"
    )

    val cameraNoteAction = SliceAction.create(
        cameraNoteIntent,
        IconCompat.createWithResource(context, R.drawable.ic_camera),
        ICON_IMAGE,
        "Create photo note"
    )

    // Construct the list.
    return list(context, sliceUri, ListBuilder.INFINITY) {
        setAccentColor(0xfff4b4) // Specify color for tinting icons
        header {
            title = "Create new note"
            subtitle = "Easily done with this note taking app"
        }
        addAction(noteAction)
        addAction(voiceNoteAction)
        addAction(cameraNoteAction)
    }
}

Java

public Slice createSliceWithActionInHeader(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    // Construct our slice actions.
    SliceAction noteAction = SliceAction.create(takeNoteIntent,
            IconCompat.createWithResource(getContext(), R.drawable.ic_pencil),
            ListBuilder.ICON_IMAGE, "Take note");

    SliceAction voiceNoteAction = SliceAction.create(voiceNoteIntent,
            IconCompat.createWithResource(getContext(), R.drawable.ic_mic),
            ListBuilder.ICON_IMAGE,
            "Take voice note");

    SliceAction cameraNoteAction = SliceAction.create(cameraNoteIntent,
            IconCompat.createWithResource(getContext(), R.drawable.ic_camera),
            ListBuilder.ICON_IMAGE,
            "Create photo note");

    // Construct the list.
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY)
            .setAccentColor(0xfff4b400) // Specify color for tinting icons
            .setHeader(new HeaderBuilder() // Construct the header.
                    .setTitle("Create new note")
                    .setSubtitle("Easily done with this note taking app")
            )
            .addRow(new RowBuilder()
                    .setTitle("Enter app")
                    .setPrimaryAction(createActivityAction())
            )
            // Add the actions to the ListBuilder.
            .addAction(noteAction)
            .addAction(voiceNoteAction)
            .addAction(cameraNoteAction);
    return listBuilder.build();
}

RowBuilder

您可以使用 RowBuilder 构造一行内容。行可以支持以下任意一项:

  • 标题
  • 副标题
  • 起始项:SliceAction、图标或时间戳
  • 结束项:SliceAction、图标或时间戳
  • 主要操作

您可以通过多种方式组合行内容,但须遵守以下限制:

  • 起始项不能显示在切片的第一行中
  • 结束项不能同时包含 SliceAction 对象和 Icon 对象
  • 一行只能包含一个时间戳

内容行示例如下图所示。请注意,灰色框表示可能的图标和内边距位置:

RowBuilder 示例 - Wi-Fi 切换开关

以下示例演示的行包含一项主要操作和一个默认切换开关。

Kotlin

fun createActionWithActionInRow(sliceUri: Uri): Slice {
    // Primary action - open wifi settings.
    val wifiAction = SliceAction.create(
        wifiSettingsPendingIntent,
        IconCompat.createWithResource(context, R.drawable.ic_wifi),
        ICON_IMAGE,
        "Wi-Fi Settings"
    )

    // Toggle action - toggle wifi.
    val toggleAction = SliceAction.createToggle(
        wifiTogglePendingIntent,
        "Toggle Wi-Fi",
        isConnected /* isChecked */
    )

    // Create the parent builder.
    return list(context, wifiUri, ListBuilder.INFINITY) {
        setAccentColor(0xff4285) // Specify color for tinting icons / controls.
        row {
            title = "Wi-Fi"
            primaryAction = wifiAction
            addEndItem(toggleAction)
        }
    }
}

Java

public Slice createActionWithActionInRow(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    // Primary action - open wifi settings.
    SliceAction primaryAction = SliceAction.create(wifiSettingsPendingIntent,
            IconCompat.createWithResource(getContext(), R.drawable.ic_wifi),
            ListBuilder.ICON_IMAGE,
            "Wi-Fi Settings"
    );

    // Toggle action - toggle wifi.
    SliceAction toggleAction = SliceAction.createToggle(wifiTogglePendingIntent,
            "Toggle Wi-Fi", isConnected /* isChecked */);

    // Create the parent builder.
    ListBuilder listBuilder = new ListBuilder(getContext(), wifiUri, ListBuilder.INFINITY)
            // Specify color for tinting icons / controls.
            .setAccentColor(0xff4285f4)
            // Create and add a row.
            .addRow(new RowBuilder()
                    .setTitle("Wi-Fi")
                    .setPrimaryAction(primaryAction)
                    .addEndItem(toggleAction));
    // Build the slice.
    return listBuilder.build();
}

GridBuilder

您可以使用 GridBuilder 构造内容网格。网格可以支持以下图片类型:

  • ICON_IMAGE:超小尺寸,可着色
  • SMALL_IMAGE:小尺寸,不可着色
  • LARGE_IMAGE:最大尺寸,不可着色

网格单元格是使用 CellBuilder 构造的。一个单元格最多可以支持两行文字和一张图片。单元格不能为空。

网格示例如下图所示:

GridRowBuilder 示例 - 附近的餐厅

以下示例演示的网格行包含图片和文字。

Kotlin

fun createSliceWithGridRow(sliceUri: Uri): Slice {
    // Create the parent builder.
    return list(context, sliceUri, ListBuilder.INFINITY) {
        header {
            title = "Famous restaurants"
            primaryAction = SliceAction.create(
                pendingIntent, icon, ListBuilder.ICON_IMAGE, "Famous restaurants"
            )
        }
        gridRow {
            cell {
                addImage(image1, LARGE_IMAGE)
                addTitleText("Top Restaurant")
                addText("0.3 mil")
                contentIntent = intent1
            }
            cell {
                addImage(image2, LARGE_IMAGE)
                addTitleText("Fast and Casual")
                addText("0.5 mil")
                contentIntent = intent2
            }
            cell {
                addImage(image3, LARGE_IMAGE)
                addTitleText("Casual Diner")
                addText("0.9 mi")
                contentIntent = intent3
            }
            cell {
                addImage(image4, LARGE_IMAGE)
                addTitleText("Ramen Spot")
                addText("1.2 mi")
                contentIntent = intent4
            }
        }
    }
}

Java

public Slice createSliceWithGridRow(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    // Create the parent builder.
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY)
            .setHeader(
                    // Create the header.
                    new HeaderBuilder()
                            .setTitle("Famous restaurants")
                            .setPrimaryAction(SliceAction
                                    .create(pendingIntent, icon, ListBuilder.ICON_IMAGE,
                                            "Famous restaurants"))
            )
            // Add a grid row to the list.
            .addGridRow(new GridRowBuilder()
                    // Add cells to the grid row.
                    .addCell(new CellBuilder()
                            .addImage(image1, ListBuilder.LARGE_IMAGE)
                            .addTitleText("Top Restaurant")
                            .addText("0.3 mil")
                            .setContentIntent(intent1)
                    ).addCell(new CellBuilder()
                            .addImage(image2, ListBuilder.LARGE_IMAGE)
                            .addTitleText("Fast and Casual")
                            .addText("0.5 mil")
                            .setContentIntent(intent2)
                    )
                    .addCell(new CellBuilder()
                            .addImage(image3, ListBuilder.LARGE_IMAGE)
                            .addTitleText("Casual Diner")
                            .addText("0.9 mi")
                            .setContentIntent(intent3))
                    .addCell(new CellBuilder()
                            .addImage(image4, ListBuilder.LARGE_IMAGE)
                            .addTitleText("Ramen Spot")
                            .addText("1.2 mi")
                            .setContentIntent(intent4))
                    // Every slice needs a primary action.
                    .setPrimaryAction(createActivityAction())
            );
    return listBuilder.build();
}

RangeBuilder

使用 RangeBuilder,您可以创建包含进度条或输入范围(如滑块)的行。

进度条和滑块示例如下图所示:

RangeBuilder 示例 - 滑块

以下示例演示了如何使用 InputRangeBuilder 构建包含音量滑块的切片。如需构造进度行,请使用 addRange()

Kotlin

fun createSliceWithRange(sliceUri: Uri): Slice {
    return list(context, sliceUri, ListBuilder.INFINITY) {
        inputRange {
            title = "Ring Volume"
            inputAction = volumeChangedPendingIntent
            max = 100
            value = 30
        }
    }
}

Java

public Slice createSliceWithRange(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    // Construct the parent.
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY)
            .addRow(new RowBuilder() // Every slice needs a row.
                    .setTitle("Enter app")
                     // Every slice needs a primary action.
                    .setPrimaryAction(createActivityAction())
            )
            .addInputRange(new InputRangeBuilder() // Create the input row.
                    .setTitle("Ring Volume")
                    .setInputAction(volumeChangedPendingIntent)
                    .setMax(100)
                    .setValue(30)
            );
    return listBuilder.build();
}

延迟的内容

您应尽快从 SliceProvider.onBindSlice() 返回切片。耗时的调用可能会导致显示问题,如闪烁和突然调整大小。

如果您的切片内容无法快速加载,您可以使用占位符内容构造切片,同时在构建器中注明内容正在加载。一旦内容可供显示,请使用切片 URI 调用 getContentResolver().notifyChange(sliceUri, null)。此时会再次调用 SliceProvider.onBindSlice(),让您可以使用新内容重新构造切片。

延迟的内容示例 - 骑车上班

在下面的“骑车上班”行中,上班距离是动态确定的,可能不会立即显示。示例代码演示了在内容加载时使用 null 副标题作为占位符:

Kotlin

fun createSliceShowingLoading(sliceUri: Uri): Slice {
    // We’re waiting to load the time to work so indicate that on the slice by
    // setting the subtitle with the overloaded method and indicate true.
    return list(context, sliceUri, ListBuilder.INFINITY) {
        row {
            title = "Ride to work"
            setSubtitle(null, true)
            addEndItem(IconCompat.createWithResource(context, R.drawable.ic_work), ICON_IMAGE)
        }
    }
}

Java

public Slice createSliceShowingLoading(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    // Construct the parent.
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY)
            // Construct the row.
            .addRow(new RowBuilder()
                    .setPrimaryAction(createActivityAction())
                    .setTitle("Ride to work")
                    // We’re waiting to load the time to work so indicate that on the slice by
                    // setting the subtitle with the overloaded method and indicate true.
                    .setSubtitle(null, true)
                    .addEndItem(IconCompat.createWithResource(getContext(), R.drawable.ic_work),
                            ListBuilder.ICON_IMAGE)
            );
    return listBuilder.build();
}

private SliceAction createActivityAction() {
    return SliceAction.create(
            PendingIntent.getActivity(
                    getContext(),
                    0,
                    new Intent(getContext(), MainActivity.class),
                    0
            ),
            IconCompat.createWithResource(getContext(), R.drawable.ic_home),
            ListBuilder.ICON_IMAGE,
            "Enter app"
    );
}

处理切片中停用滚动操作的情况

切片模板的呈现界面可能不支持在模板内滚动。在这种情况下,某些内容可能不会显示。

举例来说,假设一个切片中显示了一个 Wi-Fi 网络列表:

如果这个 Wi-Fi 列表较长,且停用了滚动操作,您可以添加查看更多按钮,以确保用户可以看到列表中的所有项目。您可以使用 addSeeMoreAction() 添加此按钮,如下例所示:

Kotlin

fun seeMoreActionSlice(sliceUri: Uri) =
    list(context, sliceUri, ListBuilder.INFINITY) {
        // ...
        setSeeMoreAction(seeAllNetworksPendingIntent)
        // ...
    }

Java

public Slice seeMoreActionSlice(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY);
    // ...
    listBuilder.setSeeMoreAction(seeAllNetworksPendingIntent);
    // ...
    return listBuilder.build();
}

显示效果如下图所示:

点按查看更多会发送 seeAllNetworksPendingIntent

或者,如果您希望提供自定义消息或行,不妨考虑添加一个 RowBuilder:

Kotlin

fun seeMoreRowSlice(sliceUri: Uri) =
    list(context, sliceUri, ListBuilder.INFINITY) {
        // ...
        seeMoreRow {
            title = "See all available networks"
            addEndItem(
                IconCompat.createWithResource(context, R.drawable.ic_right_caret), ICON_IMAGE
            )
            primaryAction = SliceAction.create(
                seeAllNetworksPendingIntent,
                IconCompat.createWithResource(context, R.drawable.ic_wifi),
                ListBuilder.ICON_IMAGE,
                "Wi-Fi Networks"
            )
        }
    }

Java

public Slice seeMoreRowSlice(Uri sliceUri) {
    if (getContext() == null) {
        return null;
    }
    ListBuilder listBuilder = new ListBuilder(getContext(), sliceUri, ListBuilder.INFINITY)
            // ...
            .setSeeMoreRow(new RowBuilder()
                    .setTitle("See all available networks")
                    .addEndItem(IconCompat
                                    .createWithResource(getContext(), R.drawable
                                            .ic_right_caret),
                            ListBuilder.ICON_IMAGE)
                    .setPrimaryAction(SliceAction.create(seeAllNetworksPendingIntent,
                            IconCompat.createWithResource(getContext(), R.drawable.ic_wifi),
                            ListBuilder.ICON_IMAGE,
                            "Wi-Fi Networks"))
            );
    // ...
    return listBuilder.build();
}

只有满足以下条件之一,通过此方法添加的行或操作才会显示出来:

  • 切片的呈现界面已停用视图上的滚动操作
  • 可用空间无法显示所有的行

组合模板

您可以将多种行类型组合在一起,创建内容丰富的动态切片。例如,切片可以包含标头行、带有单张图片的网格以及带有两个文字单元格的网格。

下面的切片包含标头行以及带有三个单元格的网格。