Question

我正在写一个游戏，可以在屏幕上拖动计数器。我想为每个计数器使用City子视图，并在ImageView父视图内设置绝对位置。

我已经阅读了一些SO帖子，介绍了各种布局类相对于已弃用的FrameLayout的优势，并且我不想使用AbsoluteLayout，因为计数器必须彼此独立地移动。这些帖子似乎都没有解决我遇到的特定问题，尽管如果有人可以指出我的建议，我会很高兴。

这是布局XML：

RelativeLayout

因为我不想对屏幕的大小做假设，所以我将每个孩子的大小设置为父屏幕大小的一小部分，放在<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/activity_game" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#ff808080"> </FrameLayout>中：

onMeasure()

出于完整性考虑，这里是我将子视图添加到父视图的地方：

package uk.co.fractalmaze.counterspin.widget

import android.content.Context
import android.graphics.Color
import android.util.Log
import android.view.ViewGroup
import android.widget.FrameLayout
import android.widget.ImageView

class CounterView(context: Context, private val label: String, private val offset: Int) : ImageView(context)
{
    init
    {
        // Set the background color.
        val color = if (offset > 0) Color.GREEN else Color.RED
        setBackgroundColor(color)
    }

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
    {
        // Set the position and size.
        val parentWidth = MeasureSpec.getSize(widthMeasureSpec)
        val parentHeight = MeasureSpec.getSize(heightMeasureSpec)
        val size = Math.min(parentWidth, parentHeight) / 2
        val left = offset * size
        Log.i(javaClass.simpleName, "Parent size ($parentWidth, $parentHeight) to $label child position ($left, 0) size $size")
        setMeasuredDimension(size, size)
        layoutParams = createLayoutParams(left, 0, size, size)
    }

    private fun createLayoutParams(left: Int, top: Int, width: Int, height: Int): ViewGroup.LayoutParams
    {
        // Create a margin params object.
        val params = FrameLayout.LayoutParams(width, height)
        params.leftMargin = left
        params.topMargin = top
        return params
    }
}

以下是结果的屏幕截图：

我希望红色和绿色的子视图可以并排显示并填充整个屏幕，但是它们合起来仅占据一半的宽度。这由logcat输出确认，该输出显示package uk.co.fractalmaze.counterspin.activity import android.os.Bundle import android.support.v7.app.AppCompatActivity import android.widget.FrameLayout import uk.co.fractalmaze.counterspin.R import uk.co.fractalmaze.counterspin.widget.CounterView class GameActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { // Call the superclass. super.onCreate(savedInstanceState) setContentView(R.layout.activity_game) // Add a left and right view to the group. val group = findViewById<FrameLayout>(R.id.activity_game) group.addView(CounterView(applicationContext, "left", 0)) group.addView(CounterView(applicationContext, "right", 1)) } }解码的父级宽度为1080，然后为540，导致子级宽度为540，然后为270。这在模拟的Pixel 3上运行，该像素3的屏幕宽度为1080像素：< / p>

MeasureSpec

谁能告诉我：

为什么父视图将自身调整为540宽度？
如何使子视图填充整个1080像素？

Answer 1

使用LinearLayout代替FrameLayout，例如：

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:weightSum="2">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:background="#ff0000">
        <!--child 1-->
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:background="#00ff00">
        <!--child 2-->
    </LinearLayout>

</LinearLayout>

Answer 2

我有一个解决方法，但是我不确定为什么会起作用。我更改了an error occurred on property 730 Trillium Ln Lilburn, GA 30047: Message: no such element: Unable to locate element: {"method":"css selector","selector":"span.current-bid"} (Session info: chrome=74.0.3729.131) (Driver info: chromedriver=2.40.565498 (ea082db3280dd6843ebfb08a625e3eb905c4f5ab),platform=Windows NT 10.0.14393 x86_64) an error occurred on property 225 Marriott Ave Schenectady, NY 12304: Message: no such element: Unable to locate element: {"method":"css selector","selector":"span.current-bid"} (Session info: chrome=74.0.3729.131) (Driver info: chromedriver=2.40.565498 (ea082db3280dd6843ebfb08a625e3eb905c4f5ab),platform=Windows NT 10.0.14393 x86_64) an error occurred on property 17 Spring Meadows Dr Ormond Beach, FL 32174: Message: no such element: Unable to locate element: {"method":"css selector","selector":"span.current-bid"} (Session info: chrome=74.0.3729.131) (Driver info: chromedriver=2.40.565498 (ea082db3280dd6843ebfb08a625e3eb905c4f5ab),platform=Windows NT 10.0.14393 x86_64) an error occurred on property 730 Trillium Ln Lilburn, GA 30047: Message: no such element: Unable to locate element: {"method":"css selector","selector":"span.current-bid"} (Session info: chrome=74.0.3729.131) (Driver info: chromedriver=2.40.565498 (ea082db3280dd6843ebfb08a625e3eb905c4f5ab),platform=Windows NT 10.0.14393 x86_64) an error occurred on property 225 Marriott Ave Schenectady, NY 12304: Message: no such element: Unable to locate element: {"method":"css selector","selector":"span.current-bid"} (Session info: chrome=74.0.3729.131) (Driver info: chromedriver=2.40.565498 (ea082db3280dd6843ebfb08a625e3eb905c4f5ab),platform=Windows NT 10.0.14393 x86_64)，以便它使用 parent 视图的所需大小创建布局参数：

CounterView.onMeasure()

这是结果：

请注意，logcat输出显示父视图大小不减半：

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
    {
        // Set the position and size.
        val parentWidth = MeasureSpec.getSize(widthMeasureSpec)
        val parentHeight = MeasureSpec.getSize(heightMeasureSpec)
        val parentSize = Math.min(parentWidth, parentHeight)
        val size = parentSize / 2
        val left = offset * size
        Log.i(javaClass.simpleName, "Parent size ($parentWidth, $parentHeight) to $label child position ($left, 0)")
        setMeasuredDimension(size, size)
        layoutParams = createLayoutParams(left, 0, parentSize, parentSize)
    }

这足以让我继续编写应用程序，但是任何人都可以解释一下这里发生了什么吗？

用子视图网格填充屏幕，但是子视图是预期大小的一半

2 个答案: