Question

我开始学习android，偶然发现了一个我现在无法解决的问题。我正在尝试使按钮的行为类似于默认的“浮动动作按钮”（以便它在与他一起上下移动时，“粘合”到小吃栏上）。我知道它是通过行为来完成的，但是直到小吃栏出现时，我才意识到按钮会弹出到空间中：D我将非常感激它的完成方向或示例。预先感谢！

这是我的xml和行为类

XML：

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/EntryScreenCoordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorWhite"
android:orientation="vertical">

<Button
    android:id="@+id/EntryScreenAccelerometerButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:text="Accelerometer screen"
    app:layout_behavior="com.example.robert.testapp.ButtonSnackbarBehaviour" />

<Button
    android:id="@+id/EntryScreenButtonToImages"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|start"
    android:text="Make Fragment"
    app:layout_behavior="com.example.robert.testapp.ButtonSnackbarBehaviour" />



<android.support.constraint.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/EntryScreenButtonToJSONLoader"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Load JSON"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toRightOf="@id/EntryScreenButtonToNoXmlFragment"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/EntryScreenButtonToNoXmlFragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/entry_screen_to_no_xml_button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@id/EntryScreenButtonToJSONLoader"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/EntryScreenButtonInternetCheck"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/entry_screen_internet_check_button"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

行为：

class ButtonSnackbarBehaviour : CoordinatorLayout.Behavior<Button> {
constructor() : super()
constructor( context:Context, attrs:AttributeSet) : super(context, attrs)

override fun layoutDependsOn(parent: CoordinatorLayout, child: Button, dependency: View): Boolean {
    return dependency is Snackbar.SnackbarLayout
}

override fun onDependentViewChanged(parent: CoordinatorLayout, child: Button, dependency: View): Boolean {
    child.y += getFabTranslationYForSnackbar(parent, child)
    return false
}

private fun getFabTranslationYForSnackbar(parent: CoordinatorLayout,
                                          button: Button): Float {
    var minOffset = 0f
    val dependencies = parent.getDependencies(button)
    var i = 0
    val z = dependencies.size
    while (i < z) {
        val view = dependencies[i]
        if (view is Snackbar.SnackbarLayout && parent.doViewsOverlap(button, view)) {
            minOffset = Math.min(minOffset,
                    ViewCompat.getTranslationY(view) - view.getHeight())
        }
        i++
    }

    return minOffset
}

}

Android：如何使Button表现得像FAB

0 个答案: