RecyclerView 设置最大高度

https://blog.51cto.com/u_14496797/5364085

方法1：使用约束布局

implementation 'androidx.constraintlayout:constraintlayout:2.0.4'

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<androidx.constraintlayout.widget.ConstraintLayout         android:id="@+id/view_constraintLayout"         android:layout_width="match_parent"         android:layout_height="wrap_content">           <androidx.recyclerview.widget.RecyclerView             android:id="@+id/rc_filter"             android:layout_width="match_parent"             app:layout_constraintTop_toTopOf="parent"             app:layout_constraintBottom_toBottomOf="parent"             app:layout_constraintLeft_toLeftOf="parent"             app:layout_constraintRight_toRightOf="parent"             android:layout_height="0dp"             app:layout_constraintHeight_default="wrap"             app:layout_constraintHeight_max="350dp" />   </androidx.constraintlayout.widget.ConstraintLayout>

　　关键代码就是

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android:layout_height="0dp" app:layout_constraintHeight_default="wrap" app:layout_constraintHeight_max="350dp"

　　

当然也可以使用 ConstraintSet 在代码中设置来实现以上代码相同的结果：

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ConstraintSet constraintSet = new ConstraintSet(); constraintSet.clone(view_constraintLayout); constraintSet.constrainMaxHeight(R.id.rc_filter,Utils.dpToPx(mContext,350)); TransitionManager.beginDelayedTransition(view_constraintLayout); constraintSet.applyTo(view_constraintLayout);

　　方法2：重写 onMessure()方法

https://blog.csdn.net/baidu_40389775/article/details/107566050

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class MaxRecyclerView : RecyclerView {     private var mMaxHeight = 0       constructor(context: Context) : super(context) {}     constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {         init(context, attrs)     }     constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {         init(context, attrs)     }       private fun init(context: Context, attrs: AttributeSet?) {         val arr = context.obtainStyledAttributes(attrs, R.styleable.MaxRecyclerView)         mMaxHeight = arr.getLayoutDimension(R.styleable.MaxRecyclerView_maxHeight, mMaxHeight)         arr.recycle()     }       override fun onMeasure(widthSpec: Int, heightSpec: Int) {         super.onMeasure(widthSpec, heightSpec)         val height = measuredHeight         if (height > mMaxHeight) {             setMeasuredDimension(widthSpec, mMaxHeight)         }     } }

　　如果测量的高度 大于 最大高度，则使用最大高度，否则默认使用测量的高度

<declare-styleable name="MaxRecyclerView">
        <attr name="maxHeight" format="dimension" />
</declare-styleable>