Question

TextInputLayout包含一个EditText，后者又接收来自用户的输入。使用Android设计支持库中引入的TextInputLayout，我们应该将错误设置为持有EditText而不是EditText本身的TextInputLayout。编写UI时，将只关注EditText而不是整个TextInputLayout，这可能导致键盘覆盖错误。在以下GIF通知中，用户必须先删除键盘才能看到错误消息。这与结合使用键盘设置IME动作相结合会导致真正令人困惑的结果。

布局xml代码：

<android.support.design.widget.TextInputLayout
    android:id="@+id/uid_text_input_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:errorEnabled="true"
    android:layout_marginTop="8dp">

    <EditText
        android:id="@+id/uid_edit_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:hint="Cardnumber"
        android:imeOptions="actionDone"/>

</android.support.design.widget.TextInputLayout>

Java代码将错误设置为TextInputLayout：

uidTextInputLayout.setError("Incorrect cardnumber");

如何在用户没有看到错误消息的情况下确保错误消息可见？是否可以移动焦点？

Answer 1

为了确保错误消息在用户没有看到它的情况下可见，我将TextInputLayout子类化并放在ScrollView内。这使我可以在需要时向下滚动以显示错误消息，在每次设置错误消息时。使用它的activity / fragment类中不需要进行任何更改。

/**
 * [TextInputLayout] subclass that handles error messages properly.
 */
class SmartTextInputLayout @JvmOverloads constructor(
        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : TextInputLayout(context, attrs, defStyleAttr) {

    private val scrollView by lazy { findParentOfType<ScrollView>() }
    private val nestedScrollView by lazy { findParentOfType<NestedScrollView>() }

    private fun scrollIfNeeded() {
        // Wait a bit (like 10 frames) for other UI changes to happen
        postDelayed({
            scrollView?.scrollDownTo(this)
            nestedScrollView?.scrollDownTo(this)
        }, 160)
    }

    override fun setError(value: CharSequence?) {
        val changed = error != value

        super.setError(value)

        // work around https://stackoverflow.com/q/34242902/1916449
        if (value == null) isErrorEnabled = false

        // work around https://stackoverflow.com/q/31047449/1916449
        if (changed) scrollIfNeeded()
    }
}

以下是辅助方法：

/**
 * Find the closest ancestor of the given type.
 */
inline fun <reified T> View.findParentOfType(): T? {
    var p = parent
    while (p != null && p !is T) p = p.parent
    return p as T?
}

/**
 * Scroll down the minimum needed amount to show [descendant] in full. More
 * precisely, reveal its bottom.
 */
fun ViewGroup.scrollDownTo(descendant: View) {
    // Could use smoothScrollBy, but it sometimes over-scrolled a lot
    howFarDownIs(descendant)?.let { scrollBy(0, it) }
}

/**
 * Calculate how many pixels below the visible portion of this [ViewGroup] is the
 * bottom of [descendant].
 *
 * In other words, how much you need to scroll down, to make [descendant]'s bottom
 * visible.
 */
fun ViewGroup.howFarDownIs(descendant: View): Int? {
    val bottom = Rect().also {
        // See https://stackoverflow.com/a/36740277/1916449
        descendant.getDrawingRect(it)
        offsetDescendantRectToMyCoords(descendant, it)
    }.bottom
    return (bottom - height - scrollY).takeIf { it > 0 }
}

我还在同一个班级中修复了TextInputLayout.setError() leaves empty space after clearing the error。

Answer 2

这实际上是Google的已知问题。

https://issuetracker.google.com/issues/37051832

他们提出的解决方案是创建一个自定义TextInputEditText类


class MyTextInputEditText : TextInputEditText {
    @JvmOverloads
    constructor(
        context: Context,
        attrs: AttributeSet? = null,
        defStyleAttr: Int = android.R.attr.editTextStyle
    ) : super(context, attrs, defStyleAttr) {
    }

    private val parentRect = Rect()

    override fun getFocusedRect(rect: Rect?) {
        super.getFocusedRect(rect)
        rect?.let {
            getMyParent().getFocusedRect(parentRect)
            rect.bottom = parentRect.bottom
        }
    }

    override fun getGlobalVisibleRect(rect: Rect?, globalOffset: Point?): Boolean {
        val result = super.getGlobalVisibleRect(rect, globalOffset)
        rect?.let {
            getMyParent().getGlobalVisibleRect(parentRect, globalOffset)
            rect.bottom = parentRect.bottom
        }
        return result
    }

    override fun requestRectangleOnScreen(rect: Rect?): Boolean {
        val result = super.requestRectangleOnScreen(rect)
        val parent = getMyParent()
        // 10 is a random magic number to define a rectangle height.
        parentRect.set(0, parent.height - 10, parent.right, parent.height)
        parent.requestRectangleOnScreen(parentRect, true /*immediate*/)
        return result;
    }

    private fun getMyParent(): View {
        var myParent: ViewParent? = parent;
        while (!(myParent is TextInputLayout) && myParent != null) {
            myParent = myParent.parent
        }
        return if (myParent == null) this else myParent as View
    }
}```

Answer 3

您应该将所有内容放在ScrollView容器中，以便用户至少可以滚动并查看错误消息。这是唯一对我有用的东西。

<ScrollView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >
        ...
        other views
        ...
    </LinearLayout>
</ScrollView>

Answer 4

@ user2221404答案对我不起作用，因此我将getMyParent（）方法更改为显示的内容：

class CustomTextInputEditText @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = android.R.attr.editTextStyle
) : TextInputEditText(context, attrs, defStyleAttr) {

private val parentRect = Rect()


override fun getFocusedRect(rect: Rect?) {
    super.getFocusedRect(rect)
    rect?.let {
        getTextInputLayout()?.getFocusedRect(parentRect)
        rect.bottom = parentRect.bottom
    }
}

override fun getGlobalVisibleRect(rect: Rect?, globalOffset: Point?): Boolean {
    val result = super.getGlobalVisibleRect(rect, globalOffset)
    rect?.let {
        getTextInputLayout()?.getGlobalVisibleRect(parentRect, globalOffset)
        rect.bottom = parentRect.bottom
    }
    return result
}

override fun requestRectangleOnScreen(rect: Rect?): Boolean {
    val result = super.requestRectangleOnScreen(rect)
    val parent = getTextInputLayout()
    // 10 is a random magic number to define a rectangle height.
    parentRect.set(0, parent?.height ?: 10 - 24, parent?.right ?: 0, parent?.height?: 0)
    parent?.requestRectangleOnScreen(parentRect, true /*immediate*/)
    return result
}

private fun getTextInputLayout(): TextInputLayout? {
    var parent = parent
    while (parent is View) {
        if (parent is TextInputLayout) {
            return parent
        }
        parent = parent.getParent()
    }
    return null
}



}

Answer 5

这很hacky，但这就是我为解决这个问题所做的工作：

因为在这种情况下我的TextInputLayout / EditText组合存在于RecyclerView中，所以我只需在设置错误时将其向上滚动：

textInputLayout.setError(context.getString(R.string.error_message))
recyclerView.scrollBy(0, context.convertDpToPixel(24f))

它有效，但肯定不太理想。如果谷歌能解决这个问题会很好，因为它肯定是一个错误。

Answer 6

晚会晚了，但是如果您已经在ScrollView / RecyclerView中，则可以通过以下简便方法解决此问题：

 editText.setOnFocusChangeListener { _, hasFocus ->
       if (hasFocus) {
         scrollBy(0,context.resources.getDimensionPixelSize(R.dimen.your_desired_dimension))
         // i would recommend 24dp
        }
  }

Answer 7

我发现如果你把容器放在固定的高度，键盘会留出错误文字的空间

<FrameLayout 
    android:layout_width="match_parent"
    android:layout_height="75dp"
    android:layout_alignParentBottom="true">

  <android.support.design.widget.TextInputLayout
    android:id="@+id/text_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    app:errorEnabled="true"
    app:errorTextAppearance="@style/ErrorText">

     <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:imeOptions="actionGo"
        android:inputType="textPersonName"
        android:singleLine="true" />
  </android.support.design.widget.TextInputLayout>
</FrameLayout>

TextInputLayout中的错误文本由键盘覆盖

7 个答案: