android - LayoutParams 不适用

Question

我正在举办 Kotlin 类(class)日。它扩展了 ViewGroup。这是 Init 函数。

import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.RectF
import android.util.AttributeSet
import android.view.View
import android.view.ViewGroup
import android.widget.LinearLayout
import android.widget.TextView
import timber.log.Timber
import java.util.*

class Day: ViewGroup {
    val date : Date;
    val dayView: View
    var color: Int = Color.TRANSPARENT

    constructor(context: Context?, date: Date) : super(context) {
        this.date = date
    }

    constructor(context: Context?, attrs: AttributeSet?, date: Date) : super(context, attrs) {
        this.date = date
    }

    constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int, date: Date) : super(
        context,
        attrs,
        defStyleAttr
    ) {
        this.date = date
    }

    constructor(
        context: Context?,
        attrs: AttributeSet?,
        defStyleAttr: Int,
        defStyleRes: Int,
        date: Date
    ) : super(context, attrs, defStyleAttr, defStyleRes) {
        this.date = date
    }

    init {
        dayView = TextView(this.context)
        dayView.text = "test"
        dayView.visibility = View.VISIBLE
        dayView.layout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)

        this.addView(dayView)
        this.setBackgroundColor(Color.CYAN)
    }

    override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) {
    }

    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)

       val paint = Paint();
        Timber.i("on draw")
        paint.strokeWidth = 5F
        paint.style = Paint.Style.FILL_AND_STROKE
        paint.color = this.color

        val pos = IntArray(2)
        this.getLocationOnScreen(pos)

        canvas?.drawArc(
            RectF(pos[0].toFloat() / 10, pos[1].toFloat() / 10, pos[0].toFloat() / 10 + 100, pos[1].toFloat() / 10 + 100),-90F, 180F, false, paint)
    }
}

构建成功后，我将对象添加到线性布局中。

val day = Day(context, Date())
this.layout.addView(day)
this.layout.requestLayout()

这些是布局的定义。

<LinearLayout
        android:orientation="vertical"
        android:id="@+id/calendarContainer"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:background="@color/colorAccent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:layout_editor_absoluteX="0dp"
        app:layout_constraintHorizontal_weight="1"
        app:layout_constraintVertical_weight="1">

但结果并不像预期的那样。因为我希望 TextView 与父级一样高和宽，但没有显示 textview。绘制的圆只显示一个。

新的 onLayout 实现。

override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) {
    this.children.forEach {
        it.left = left
        it.top = top

        if(it.layoutParams.width == LayoutParams.MATCH_PARENT){
            it.right = right
        }

        if(it.layoutParams.height == LayoutParams.MATCH_PARENT){
            it.bottom = bottom
        }
        it.textAlignment = View.TEXT_ALIGNMENT_CENTER

        it.layoutParams = LayoutParams(right,bottom)
        Timber.i("right: " + right)

        Timber.i("height: " + it.width.toString())
        Timber.i("width: " + it.height.toString())
    }
}

Answer 1

问题是，onLayout 函数没有像@Enselic 所说的那样实现。

首先，我尝试自己实现布局。但是有一个更简单的方法:

override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) {
    if(changed){
        this.children.forEach {
//delegating the layouting to the element
            it.layout(left,top,right,bottom)
        }
    }
}