RecyclerView限制最大高度或宽度

在日常开发中，想直接通过android:maxHeight或android:maxWidth在布局文件中限制RecyclerView的最大高度宽度，是无法实现的。通过自定义RecyclerView，覆盖onMeasure方法。在onMeasure方法内部，当发现自身高度或宽度超过限制的最大高度或宽度，则手动将宽或高设置为期望的最大宽或搞。具体代码实现如下：

/**
 * max limit-able RecyclerView
 */
public class MaxLimitRecyclerView extends RecyclerView {
private int mMaxHeight;
private int mMaxWidth;
public MaxLimitRecyclerView(Context context) {
   this(context, null);
}

public MaxLimitRecyclerView(Context context, @Nullable AttributeSet attrs) {
   this(context, attrs, 0);
}

public MaxLimitRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    inti(attrs);
}
private void inti(AttributeSet attrs) {
    if (getContext() != null && attrs != null) {
    TypedArray typedArray = null;
    try {
        typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.MaxLimitRecyclerView);
    if (typedArray.hasValue(R.styleable.MaxLimitRecyclerView_limit_maxHeight)) {
            mMaxHeight = typedArray.getDimensionPixelOffset(R.styleable.MaxLimitRecyclerView_limit_maxHeight, -1);
        }
        if (typedArray.hasValue(R.styleable.MaxLimitRecyclerView_limit_maxWidth)) {
            mMaxWidth = typedArray.getDimensionPixelOffset(R.styleable.MaxLimitRecyclerView_limit_maxWidth, -1);
        }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (typedArray != null) {
                typedArray.recycle();
            }
        }
    }
}

@Override
protected void onMeasure(int widthSpec, int heightSpec) {
    super.onMeasure(widthSpec, heightSpec);
    boolean needLimit = false;
    if (mMaxHeight >= 0 || mMaxWidth >= 0) {
        needLimit = true;
    }
    if (needLimit) {
        int limitHeight = getMeasuredHeight();
        int limitWith = getMeasuredWidth();
        if (getMeasuredHeight() > mMaxHeight) {
            limitHeight = mMaxHeight;
        }
        if (getMeasuredWidth() > mMaxWidth) {
            limitWith = mMaxWidth;
        }
        setMeasuredDimension(limitWith, limitHeight);
    }
}
}

对应属性xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!--attribute for MaxLimitRecyclerView-->
    <declare-styleable name="MaxLimitRecyclerView">
        <attr name="limit_maxHeight" format="reference|dimension" />
        <attr name="limit_maxWidth" format="reference|dimension" />
    </declare-styleable>
</resources>

使用方式：

<your_package_name.MaxLimitRecyclerView
        android:id="@+id/act_choose_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"             
        app:limit_maxHeight="100dp"
        tools:itemCount="8" />

以上，便可实现对RecyclerView最大高度或宽度的限制。