Question

我正在制作一个阅读应用程序，它有一个全屏活动当用户选择文本的一部分时，会出现contextual action bar并带有复制选项。这是默认行为。但是此操作栏会阻止其下的文本，因此用户无法选择它。

我想显示如下的弹出窗口。

我尝试从false返回onCreateActionMode，但是当我这样做时，我也无法选择文字。

我想知道是否有一种标准的方法来实现这一点，因为许多阅读应用程序都使用这种设计。

Answer 1

我不知道Play Books如何实现这一目标，但您可以使用PopupWindow创建一个Layout.getSelectionPath并根据所选文本计算位置，并进行一些数学计算。基本上，我们要去：

计算所选文本的范围
计算PopupWindow
计算两者之间的差异
将PopupWindow偏移到水平/垂直于所选文字上方或下方的休息中心

计算选择范围

From the docs：

使用高亮显示填充指定的路径在指定的偏移之间。这通常是一个矩形或一个可能不连续的矩形集。如果是开始和结束同样，返回的路径是空的。

因此，我们案例中指定的偏移量将是选择的开始和结束，可以使用Selection.getSelectionStart和Selection.getSelectionEnd找到。为方便起见，TextView为我们提供了TextView.getSelectionStart，TextView.getSelectionEnd和TextView.getLayout。

    final Path selDest = new Path();
    final RectF selBounds = new RectF();
    final Rect outBounds = new Rect();

    // Calculate the selection start and end offset
    final int selStart = yourTextView.getSelectionStart();
    final int selEnd = yourTextView.getSelectionEnd();
    final int min = Math.max(0, Math.min(selStart, selEnd));
    final int max = Math.max(0, Math.max(selStart, selEnd));

    // Calculate the selection outBounds
    yourTextView.getLayout().getSelectionPath(min, max, selDest);
    selDest.computeBounds(selBounds, true /* this param is ignored */);
    selBounds.roundOut(outBounds);

现在我们有Rect个选定的文本边界，我们可以选择相对于它放置PopupWindow的位置。在这种情况下，我们将它沿着所选文本的顶部或底部水平居中，具体取决于我们显示弹出窗口的空间大小。

计算初始弹出坐标

接下来我们需要计算弹出内容的界限。要做到这一点，我们首先需要致电PopupWindow.showAtLocation，但我们膨胀的View的界限不会立即可用，因此我建议使用{ {3}}等待他们变得可用。

popupWindow.showAtLocation(yourTextView, Gravity.TOP, 0, 0)

PopupWindow.showAtLocation要求：

View从中检索有效的ViewTreeObserver.OnGlobalLayoutListener，它只是唯一标识Window以放置弹出广告
可选的重力，但在我们的情况下，它将是Gravity.TOP
可选的x / y偏移

由于我们无法确定弹出内容布局之前的x / y偏移量，因此我们最初将其放置在默认位置。如果您在传递的PopupWindow.showAtLocation之前尝试拨打View，则会收到Window token，因此您可以考虑使用ViewTreeObserver.OnGlobalLayoutListener来final Rect cframe = new Rect(); final int[] cloc = new int[2]; popupContent.getLocationOnScreen(cloc); popupContent.getLocalVisibleRect(cbounds); popupContent.getWindowVisibleDisplayFrame(cframe); final int scrollY = ((View) yourTextView.getParent()).getScrollY(); final int[] tloc = new int[2]; yourTextView.getLocationInWindow(tloc); final int startX = cloc[0] + cbounds.centerX(); final int startY = cloc[1] + cbounds.centerY() - (tloc[1] - cframe.top) - scrollY;避免这种情况，但是当您选择了文本并旋转设备时，它通常会出现。

WindowManager.BadTokenException会返回弹出内容的x / y坐标。
View.getLocationOnScreen会返回弹出内容的界限
View.getLocalVisibleRect会返回偏移以适应操作栏（如果存在）
View.getWindowVisibleDisplayFrame会返回我们TextView所在的滚动容器的ScrollView偏移量（在我的情况下为y）
View.getScrollY会返回我们TextView的{{1}}偏移量，以防操作栏将其推下一点

一旦我们获得了所需的所有信息，我们就可以计算弹出内容的最终起始x / y，然后使用它来计算它们与所选文本之间的差异Rect所以我们可以View.getLocationInWindow到新的位置。

计算偏移弹出坐标

    // Calculate the top and bottom offset of the popup relative to the selection bounds
    final int popupHeight = cbounds.height();
    final int textPadding = yourTextView.getPaddingLeft();
    final int topOffset = Math.round(selBounds.top - startY);
    final int btmOffset = Math.round(selBounds.bottom - (startY - popupHeight));

    // Calculate the x/y coordinates for the popup relative to the selection bounds
    final int x = Math.round(selBounds.centerX() + textPadding - startX);
    final int y = Math.round(selBounds.top - scrollY < startY ? btmOffset : topOffset);

如果有足够的空间在所选文字上方显示弹出窗口，我们会把它放在那里;否则，我们会将其偏移到选定文本下方。就我而言，我16dp周围有TextView填充，因此也需要考虑。我们最终会使用最终x和y位置来抵消PopupWindow。

    popupWindow.update(x, y, -1, -1);

-1这里只代表我们为PopupWindow提供的默认宽度/高度，在我们的例子中它将是PopupWindow.update

聆听选择更改

我们希望每次更改所选文本时PopupWindow都会更新。

监听选择更改的一种简单方法是继承TextView并提供对ViewGroup.LayoutParams.WRAP_CONTENT的回调。

public class NotifyingSelectionTextView extends AppCompatTextView {

    private SelectionChangeListener listener;

    public NotifyingSelectionTextView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onSelectionChanged(int selStart, int selEnd) {
        super.onSelectionChanged(selStart, selEnd);
        if (listener != null) {
            if (hasSelection()) {
                listener.onTextSelected();
            } else {
                listener.onTextUnselected();
            }
        }
    }

    public void setSelectionChangeListener(SelectionChangeListener listener) {
        this.listener = listener;
    }

    public interface SelectionChangeListener {
        void onTextSelected();
        void onTextUnselected();
    }

}

聆听滚动更改

如果您在TextView等滚动容器中有ScrollView，则可能还需要侦听滚动更改，以便在滚动时锚定弹出窗口。听取这些内容的简单方法是继承ScrollView并提供对TextView.onSelectionChanged的回调

public class NotifyingScrollView extends ScrollView {

    private ScrollChangeListener listener;

    public NotifyingScrollView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        super.onScrollChanged(l, t, oldl, oldt);
        if (listener != null) {
            listener.onScrollChanged();
        }
    }

    public void setScrollChangeListener(ScrollChangeListener listener) {
        this.listener = listener;
    }

    public interface ScrollChangeListener {
        void onScrollChanged();
    }

}

创建一个空的View.onScrollChanged

就像您在帖子中提到的那样，我们需要在ActionMode.Callback中返回true，以便我们的文字仍然可以选择。但我们还需要在ActionMode.Callback.onCreateActionMode中致电Menu.clear，以便删除您在ActionMode中为所选文字找到的所有项目。

/** An {@link ActionMode.Callback} used to remove all action items from text selection */
static final class EmptyActionMode extends SimpleActionModeCallback {

    @Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        // Return true to ensure the text is still selectable
        return true;
    }

    @Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        // Remove all action items to provide an actionmode-less selection
        menu.clear();
        return true;
    }

}

现在我们可以使用ActionMode.Callback.onPrepareActionMode来应用我们的自定义ActionMode。 SimpleActionModeCallback是一个自定义类，仅为ActionMode.Callback提供存根，类似于TextView.setCustomSelectionActionModeCallback

public class SimpleActionModeCallback implements ActionMode.Callback {

    @Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        return false;
    }

    @Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        return false;
    }

    @Override
    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        return false;
    }

    @Override
    public void onDestroyActionMode(ActionMode mode) {

    }

}

<强>布局

这是我们正在使用的Activity布局：

<your.package.name.NotifyingScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/notifying_scroll_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <your.package.name.NotifyingSelectionTextView
        android:id="@+id/notifying_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="16dp"
        android:textIsSelectable="true"
        android:textSize="20sp" />

</your.package.name.NotifyingScrollView>

这是我们的弹出式布局：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/action_mode_popup_bg"
    android:orientation="vertical"
    tools:ignore="ContentDescription">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <ImageButton
            android:id="@+id/view_action_mode_popup_add_note"
            style="@style/ActionModePopupButton"
            android:src="@drawable/ic_note_add_black_24dp" />

        <ImageButton
            android:id="@+id/view_action_mode_popup_translate"
            style="@style/ActionModePopupButton"
            android:src="@drawable/ic_translate_black_24dp" />

        <ImageButton
            android:id="@+id/view_action_mode_popup_search"
            style="@style/ActionModePopupButton"
            android:src="@drawable/ic_search_black_24dp" />

    </LinearLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_margin="8dp"
        android:background="@android:color/darker_gray" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <ImageButton
            android:id="@+id/view_action_mode_popup_red"
            style="@style/ActionModePopupSwatch"
            android:src="@drawable/round_red" />

        <ImageButton
            android:id="@+id/view_action_mode_popup_yellow"
            style="@style/ActionModePopupSwatch"
            android:src="@drawable/round_yellow" />

        <ImageButton
            android:id="@+id/view_action_mode_popup_green"
            style="@style/ActionModePopupSwatch"
            android:src="@drawable/round_green" />

        <ImageButton
            android:id="@+id/view_action_mode_popup_blue"
            style="@style/ActionModePopupSwatch"
            android:src="@drawable/round_blue" />

        <ImageButton
            android:id="@+id/view_action_mode_popup_clear_format"
            style="@style/ActionModePopupSwatch"
            android:src="@drawable/ic_format_clear_black_24dp"
            android:visibility="gone" />

    </LinearLayout>

</LinearLayout>

这些是我们的弹出按钮样式：

<style name="ActionModePopupButton">
    <item name="android:layout_width">48dp</item>
    <item name="android:layout_height">48dp</item>
    <item name="android:layout_weight">1</item>
    <item name="android:background">?selectableItemBackground</item>
</style>

<style name="ActionModePopupSwatch" parent="ActionModePopupButton">
    <item name="android:padding">12dp</item>
</style>

<强>的Util

您将看到的ViewUtils.onGlobalLayout只是处理某些ViewTreeObserver.OnGlobalLayoutListener样板的util方法。

public static void onGlobalLayout(final View view, final Runnable runnable) {
    final OnGlobalLayoutListener listener = new OnGlobalLayoutListener() {

        @Override
        public void onGlobalLayout() {
            view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            runnable.run();
        }

    };
    view.getViewTreeObserver().addOnGlobalLayoutListener(listener);
}

完全带来

所以，现在我们已经：

计算选定的文本范围
计算弹出范围
计算差异并确定弹出偏移量
提供了一种监听滚动更改和选择更改的方法
创建了我们的Activity和弹出式布局

把所有东西放在一起可能看起来像：

public class ActionModePopupActivity extends AppCompatActivity
        implements ScrollChangeListener, SelectionChangeListener {

    private static final int DEFAULT_WIDTH = -1;
    private static final int DEFAULT_HEIGHT = -1;

    private final Point currLoc = new Point();
    private final Point startLoc = new Point();

    private final Rect cbounds = new Rect();
    private final PopupWindow popupWindow = new PopupWindow();
    private final ActionMode.Callback emptyActionMode = new EmptyActionMode();

    private NotifyingSelectionTextView yourTextView;

    @SuppressLint("InflateParams")
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_action_mode_popup);

        // Initialize the popup content, only add it to the Window once we've selected text
        final LayoutInflater inflater = LayoutInflater.from(this);
        popupWindow.setContentView(inflater.inflate(R.layout.view_action_mode_popup, null));
        popupWindow.setWidth(WRAP_CONTENT);
        popupWindow.setHeight(WRAP_CONTENT);

        // Initialize to the NotifyingScrollView to observe scroll changes
        final NotifyingScrollView scroll
                = (NotifyingScrollView) findViewById(R.id.notifying_scroll_view);
        scroll.setScrollChangeListener(this);

        // Initialize the TextView to observe selection changes and provide an empty ActionMode
        yourTextView = (NotifyingSelectionTextView) findViewById(R.id.notifying_text_view);
        yourTextView.setText(IPSUM);
        yourTextView.setSelectionChangeListener(this);
        yourTextView.setCustomSelectionActionModeCallback(emptyActionMode);
    }

    @Override
    public void onScrollChanged() {
        // Anchor the popup while the user scrolls
        if (popupWindow.isShowing()) {
            final Point ploc = calculatePopupLocation();
            popupWindow.update(ploc.x, ploc.y, DEFAULT_WIDTH, DEFAULT_HEIGHT);
        }
    }

    @Override
    public void onTextSelected() {
        final View popupContent = popupWindow.getContentView();
        if (popupWindow.isShowing()) {
            // Calculate the updated x/y pop coordinates
            final Point ploc = calculatePopupLocation();
            popupWindow.update(ploc.x, ploc.y, DEFAULT_WIDTH, DEFAULT_HEIGHT);
        } else {
        // Add the popup to the Window and position it relative to the selected text bounds
        ViewUtils.onGlobalLayout(yourTextView, () -> {
            popupWindow.showAtLocation(yourTextView, TOP, 0, 0);
            // Wait for the popup content to be laid out
            ViewUtils.onGlobalLayout(popupContent, () -> {
                final Rect cframe = new Rect();
                final int[] cloc = new int[2];
                popupContent.getLocationOnScreen(cloc);
                popupContent.getLocalVisibleRect(cbounds);
                popupContent.getWindowVisibleDisplayFrame(cframe);

                final int scrollY = ((View) yourTextView.getParent()).getScrollY();
                final int[] tloc = new int[2];
                yourTextView.getLocationInWindow(tloc);

                final int startX = cloc[0] + cbounds.centerX();
                final int startY = cloc[1] + cbounds.centerY() - (tloc[1] - cframe.top) - scrollY;
                startLoc.set(startX, startY);

                final Point ploc = calculatePopupLocation();
                popupWindow.update(ploc.x, ploc.y, DEFAULT_WIDTH, DEFAULT_HEIGHT);
            });
        });
        }
    }

    @Override
    public void onTextUnselected() {
        popupWindow.dismiss();
    }

    /** Used to calculate where we should position the {@link PopupWindow} */
    private Point calculatePopupLocation() {
        final ScrollView parent = (ScrollView) yourTextView.getParent();

        // Calculate the selection start and end offset
        final int selStart = yourTextView.getSelectionStart();
        final int selEnd = yourTextView.getSelectionEnd();
        final int min = Math.max(0, Math.min(selStart, selEnd));
        final int max = Math.max(0, Math.max(selStart, selEnd));

        // Calculate the selection bounds
        final RectF selBounds = new RectF();
        final Path selection = new Path();
        yourTextView.getLayout().getSelectionPath(min, max, selection);
        selection.computeBounds(selBounds, true /* this param is ignored */);

        // Retrieve the center x/y of the popup content
        final int cx = startLoc.x;
        final int cy = startLoc.y;

        // Calculate the top and bottom offset of the popup relative to the selection bounds
        final int popupHeight = cbounds.height();
        final int textPadding = yourTextView.getPaddingLeft();
        final int topOffset = Math.round(selBounds.top - cy);
        final int btmOffset = Math.round(selBounds.bottom - (cy - popupHeight));

        // Calculate the x/y coordinates for the popup relative to the selection bounds
        final int scrollY = parent.getScrollY();
        final int x = Math.round(selBounds.centerX() + textPadding - cx);
        final int y = Math.round(selBounds.top - scrollY < cy ? btmOffset : topOffset);
        currLoc.set(x, y - scrollY);
        return currLoc;
    }

    /** An {@link ActionMode.Callback} used to remove all action items from text selection */
    static final class EmptyActionMode extends SimpleActionModeCallback {

        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            // Return true to ensure the yourTextView is still selectable
            return true;
        }

        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            // Remove all action items to provide an actionmode-less selection
            menu.clear();
            return true;
        }

    }

}

<强>结果

ViewPager.SimpleOnPageChangeListener：

With the action bar (link to video)

：

Without the action bar (link to video)

奖金 - 动画

因为随着选择的变化我们知道PopupWindow的起始位置和偏移位置，我们可以轻松地在两个值之间执行线性插值，以便在我们移动物体时创建一个漂亮的动画

public static float lerp(float a, float b, float v) {
    return a + (b - a) * v;
}

private static final int DEFAULT_ANIM_DUR = 350;
private static final int DEFAULT_ANIM_DELAY = 500;

@Override
public void onTextSelected() {
    final View popupContent = popupWindow.getContentView();
    if (popupWindow.isShowing()) {
        // Calculate the updated x/y pop coordinates
        popupContent.getHandler().removeCallbacksAndMessages(null);
        popupContent.postDelayed(() -> {
            // The current x/y location of the popup
            final int currx = currLoc.x;
            final int curry = currLoc.y;
            // Calculate the updated x/y pop coordinates
            final Point ploc = calculatePopupLocation();
            currLoc.set(ploc.x, ploc.y);
            // Linear interpolate between the current and updated popup coordinates
            final ValueAnimator anim = ValueAnimator.ofFloat(0f, 1f);
            anim.addUpdateListener(animation -> {
                final float v = (float) animation.getAnimatedValue();
                final int x = Math.round(AnimUtils.lerp(currx, ploc.x, v));
                final int y = Math.round(AnimUtils.lerp(curry, ploc.y, v));
                popupWindow.update(x, y, DEFAULT_WIDTH, DEFAULT_HEIGHT);
            });
            anim.setDuration(DEFAULT_ANIM_DUR);
            anim.start();
        }, DEFAULT_ANIM_DELAY);
    } else {
        ...
    }
}

<强>结果

With the action bar - animation (link to video)

<强>附加

我没有讨论如何将点击侦听器附加到弹出操作上，并且可能有多种方法可以通过不同的计算和实现来实现相同的效果。但我要提一下，如果您想要检索所选文本，然后对其执行某些操作，。

无论如何，我希望这对你有所帮助！如果您有任何问题，请告诉我。

选择textview时如何显示弹出窗口而不是CAB？

1 个答案: