Question

我在布局中有以下卡片：

<android.support.v7.widget.CardView
    android:id="@+id/card1"
    android:layout_width="match_parent"
    android:layout_marginBottom="6dp">

    <RelativeLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

        <!-- [a RecyclerView as list with LinearLayout as header] -->
        <include
            android:id="@+id/table"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_above="@+id/total_label"
            android:layout_below="@id/label"
            android:layout_marginBottom="4dp"
            android:layout_marginTop="4dp" />

        <!-- [a LinearLayout with 2 TextViews] -->
        <include
            android:id="@+id/total_label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true" />

    </RelativeLayout>
</android.support.v7.widget.CardView>

我尝试实现的是点击标签TextView并隐藏卡中的其他内容（仅显示其标签组件）。再次，通过进一步单击标签，展开隐藏的内容。我可以这样做，如果我明确设置卡的高度，即400dp，但是如果用作列表的包含RecyclerView没有多少项（所有都是相同的高度和固定），那么很空的空间。卡片如何包装其内容？（当我在卡片的wrap_content中使用layout_height时，只有标签可见。）

这是卡片的点击处理程序：

card.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Resources r = getResources();

                if (toggle) {
                    tableContainer.setVisibility(View.GONE);
                    totalLabel.setVisibility(View.GONE);

                    LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);

                    float pxTopMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, getResources().getDimension(R.dimen.card_list_margin_top), r.getDisplayMetrics());

                    params.topMargin = (int) pxTopMargin;

                    card.setLayoutParams(params);
                    card.setVisibility(View.GONE);
                    card.setVisibility(View.VISIBLE);
                } else {
                    tableContainer.setVisibility(View.VISIBLE);
                    totalLabel.setVisibility(View.VISIBLE);


                    float pxHeight = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 400, r.getDisplayMetrics());

                    LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, (int) pxHeight);

                    float pxTopMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, getResources().getDimension(R.dimen.card_list_margin_top), r.getDisplayMetrics());

                    params.topMargin = (int) pxTopMargin;
                    params.bottomMargin = (int) pxTopMargin;

                    card.setLayoutParams(params);
                    card.setVisibility(View.GONE);
                    card.setVisibility(View.VISIBLE);
                }

                toggle = !toggle;
            }
        });

解

确定问题实际上是使用具有属性的RecyclerView创建列表：

要显示的特定行数（即15），如果低，则将其内容包装

我从other SO thread（由 se.solovyev 评论）发现了一个自定义线性布局并进行了一些编辑。结果令人满意（虽然我实际上并不知道在那里做了什么非常糟糕的事情，但有效）。

package com.trafficbroker.trafficbroker.views;

import android.content.Context;
import android.graphics.Rect;
import android.support.v4.view.ViewCompat;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;

import java.lang.reflect.Field;

/**
 * {@link android.support.v7.widget.LinearLayoutManager} which wraps its content. Note that this class will always
 * wrap the content regardless of {@link android.support.v7.widget.RecyclerView} layout parameters.
 * <p/>
 * Now it's impossible to run add/remove animations with child views which have arbitrary dimensions (height for
 * VERTICAL orientation and width for HORIZONTAL). However if child views have fixed dimensions
 * {@link #setChildSize(int)} method might be used to let the layout manager know how big they are going to be.
 * If animations are not used at all then a normal measuring procedure will run and child views will be measured during
 * the measure pass.
 */
public class WrappingLinearLayoutManager extends    android.support.v7.widget.LinearLayoutManager {

private static boolean canMakeInsetsDirty = true;
private static Field insetsDirtyField = null;

private static final int CHILD_WIDTH = 0;
private static final int CHILD_HEIGHT = 1;
private static final int DEFAULT_CHILD_SIZE = 100;

private final int[] childDimensions = new int[2];
private final RecyclerView view;

private int childSize = DEFAULT_CHILD_SIZE;
private boolean hasChildSize;
private int overScrollMode = ViewCompat.OVER_SCROLL_ALWAYS;
private final Rect tmpRect = new Rect();

@SuppressWarnings("UnusedDeclaration")
public WrappingLinearLayoutManager(Context context) {
    super(context);
    this.view = null;
}

@SuppressWarnings("UnusedDeclaration")
public WrappingLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
    super(context, orientation, reverseLayout);
    this.view = null;
}

@SuppressWarnings("UnusedDeclaration")
public WrappingLinearLayoutManager(RecyclerView view) {
    super(view.getContext());
    this.view = view;
    this.overScrollMode = ViewCompat.getOverScrollMode(view);
}

@SuppressWarnings("UnusedDeclaration")
public WrappingLinearLayoutManager(RecyclerView view, int orientation, boolean reverseLayout) {
    super(view.getContext(), orientation, reverseLayout);
    this.view = view;
    this.overScrollMode = ViewCompat.getOverScrollMode(view);
}

public void setOverScrollMode(int overScrollMode) {
    if (overScrollMode < ViewCompat.OVER_SCROLL_ALWAYS || overScrollMode > ViewCompat.OVER_SCROLL_NEVER)
        throw new IllegalArgumentException("Unknown overscroll mode: " + overScrollMode);
    if (this.view == null) throw new IllegalStateException("view == null");
    this.overScrollMode = overScrollMode;
    ViewCompat.setOverScrollMode(view, overScrollMode);
}

public static int makeUnspecifiedSpec() {
    return View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
}

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);

    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);

    final boolean hasWidthSize = widthMode != View.MeasureSpec.UNSPECIFIED;
    final boolean hasHeightSize = heightMode != View.MeasureSpec.UNSPECIFIED;

    final boolean exactWidth = widthMode == View.MeasureSpec.EXACTLY;
    final boolean exactHeight = heightMode == View.MeasureSpec.EXACTLY;

    final int unspecified = makeUnspecifiedSpec();

    if (exactWidth && exactHeight) {
        // in case of exact calculations for both dimensions let's use default "onMeasure" implementation
        super.onMeasure(recycler, state, widthSpec, heightSpec);
        return;
    }

    final boolean vertical = getOrientation() == VERTICAL;

    initChildDimensions(widthSize, heightSize, vertical);

    int width = 0;
    int height = 0;

    // it's possible to get scrap views in recycler which are bound to old (invalid) adapter entities. This
    // happens because their invalidation happens after "onMeasure" method. As a workaround let's clear the
    // recycler now (it should not cause any performance issues while scrolling as "onMeasure" is never
    // called whiles scrolling)
    recycler.clear();

    final int stateItemCount = state.getItemCount();
    final int adapterItemCount = (getItemCount() < 15 ? getItemCount() : 15);//getItemCount();   // MAX VISIBLE ROWS
    // adapter always contains actual data while state might contain old data (f.e. data before the animation is
    // done). As we want to measure the view with actual data we must use data from the adapter and not from  the
    // state
    for (int i = 0; i < adapterItemCount; i++) {
        if (vertical) {
            if (!hasChildSize) {
                if (i < stateItemCount) {
                    // we should not exceed state count, otherwise we'll get IndexOutOfBoundsException. For such items
                    // we will use previously calculated dimensions
                    measureChild(recycler, i, widthSize, unspecified, childDimensions);
                } else {
                    logMeasureWarning(i);
                }
            }
            height += childDimensions[CHILD_HEIGHT];
            if (i == 0) {
                width = childDimensions[CHILD_WIDTH];
            }
            if (hasHeightSize && height >= heightSize) {
                break;
            }
        } else {
            if (!hasChildSize) {
                if (i < stateItemCount) {
                    // we should not exceed state count, otherwise we'll get IndexOutOfBoundsException. For such items
                    // we will use previously calculated dimensions
                    measureChild(recycler, i, unspecified, heightSize, childDimensions);
                } else {
                    logMeasureWarning(i);
                }
            }
            width += childDimensions[CHILD_WIDTH];
            if (i == 0) {
                height = childDimensions[CHILD_HEIGHT];
            }
            if (hasWidthSize && width >= widthSize) {
                break;
            }
        }
    }

    if (exactWidth) {
        width = widthSize;
    } else {
        width += getPaddingLeft() + getPaddingRight();
        if (hasWidthSize) {
            width = Math.min(width, widthSize);
        }
    }

    if (exactHeight) {
        height = heightSize;
    } else {
        height += getPaddingTop() + getPaddingBottom();
        if (hasHeightSize) {
            height = Math.min(height, heightSize);
        }
    }

    setMeasuredDimension(width, height);

    if (view != null && overScrollMode == ViewCompat.OVER_SCROLL_IF_CONTENT_SCROLLS) {
        final boolean fit = (vertical && (!hasHeightSize || height < heightSize))
                || (!vertical && (!hasWidthSize || width < widthSize));

        ViewCompat.setOverScrollMode(view, fit ? ViewCompat.OVER_SCROLL_NEVER : ViewCompat.OVER_SCROLL_ALWAYS);
    }
}

private void logMeasureWarning(int child) {
    if (BuildConfig.DEBUG) {
        Log.w("LinearLayoutManager", "Can't measure child #" + child + ", previously used dimensions will be reused." +
                "To remove this message either use #setChildSize() method or don't run RecyclerView animations");
    }
}

private void initChildDimensions(int width, int height, boolean vertical) {
    if (childDimensions[CHILD_WIDTH] != 0 || childDimensions[CHILD_HEIGHT] != 0) {
        // already initialized, skipping
        return;
    }
    if (vertical) {
        childDimensions[CHILD_WIDTH] = width;
        childDimensions[CHILD_HEIGHT] = childSize;
    } else {
        childDimensions[CHILD_WIDTH] = childSize;
        childDimensions[CHILD_HEIGHT] = height;
    }
}

@Override
public void setOrientation(int orientation) {
    // might be called before the constructor of this class is called
    //noinspection ConstantConditions
    if (childDimensions != null) {
        if (getOrientation() != orientation) {
            childDimensions[CHILD_WIDTH] = 0;
            childDimensions[CHILD_HEIGHT] = 0;
        }
    }
    super.setOrientation(orientation);
}

public void clearChildSize() {
    hasChildSize = false;
    setChildSize(DEFAULT_CHILD_SIZE);
}

public void setChildSize(int childSize) {
    hasChildSize = true;
    if (this.childSize != childSize) {
        this.childSize = childSize;
        requestLayout();
    }
}

private void measureChild(RecyclerView.Recycler recycler, int position, int widthSize, int heightSize, int[] dimensions) {
    final View child;
    try {
        child = recycler.getViewForPosition(position);
    } catch (IndexOutOfBoundsException e) {
        if (BuildConfig.DEBUG) {
            Log.w("LinearLayoutManager", "LinearLayoutManager doesn't work well with animations. Consider switching them off", e);
        }
        return;
    }

    final RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) child.getLayoutParams();

    final int hPadding = getPaddingLeft() + getPaddingRight();
    final int vPadding = getPaddingTop() + getPaddingBottom();

    final int hMargin = p.leftMargin + p.rightMargin;
    final int vMargin = p.topMargin + p.bottomMargin;

    // we must make insets dirty in order calculateItemDecorationsForChild to work
    makeInsetsDirty(p);
    // this method should be called before any getXxxDecorationXxx() methods
    calculateItemDecorationsForChild(child, tmpRect);

    final int hDecoration = getRightDecorationWidth(child) + getLeftDecorationWidth(child);
    final int vDecoration = getTopDecorationHeight(child) + getBottomDecorationHeight(child);

    final int childWidthSpec = getChildMeasureSpec(widthSize, hPadding + hMargin + hDecoration, p.width, canScrollHorizontally());
    final int childHeightSpec = getChildMeasureSpec(heightSize, vPadding + vMargin + vDecoration, p.height, canScrollVertically());

    child.measure(childWidthSpec, childHeightSpec);

    dimensions[CHILD_WIDTH] = getDecoratedMeasuredWidth(child) + p.leftMargin + p.rightMargin;
    dimensions[CHILD_HEIGHT] = getDecoratedMeasuredHeight(child) + p.bottomMargin + p.topMargin;

    // as view is recycled let's not keep old measured values
    makeInsetsDirty(p);
    recycler.recycleView(child);
}

private static void makeInsetsDirty(RecyclerView.LayoutParams p) {
    if (!canMakeInsetsDirty) {
        return;
    }
    try {
        if (insetsDirtyField == null) {
            insetsDirtyField = RecyclerView.LayoutParams.class.getDeclaredField("mInsetsDirty");
            insetsDirtyField.setAccessible(true);
        }
        insetsDirtyField.set(p, true);
    } catch (NoSuchFieldException e) {
        onMakeInsertDirtyFailed();
    } catch (IllegalAccessException e) {
        onMakeInsertDirtyFailed();
    }
}

private static void onMakeInsertDirtyFailed() {
    canMakeInsetsDirty = false;
    if (BuildConfig.DEBUG) {
        Log.w("LinearLayoutManager", "Can't make LayoutParams insets dirty, decorations measurements might be incorrect");
    }
}
}

Answer 1

我做了一个尽可能接近你的例子，但关键似乎是

card.requestLayout();

这就是我对CardView的看法

    <android.support.v7.widget.CardView
    android:id="@+id/card1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="6dp">

    <RelativeLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            />

        <!-- [a RecyclerView as list with LinearLayout as header] -->
        <include
            layout="@layout/table_container"

            android:id="@+id/table"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/label"
            android:layout_marginBottom="4dp"
            android:layout_marginTop="4dp" />

        <!-- [a LinearLayout with 2 TextViews] -->
        <include
            layout="@layout/total_label"
            android:id="@+id/total_label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/table" />


    </RelativeLayout>
</android.support.v7.widget.CardView>

这是我为听众所做的事情

card.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (toggle) {
                tableContainer.setVisibility(View.GONE);
                totalLabel.setVisibility(View.GONE);

                //ViewGroup.LayoutParams params = tableContainer.getLayoutParams();
                //params.height = 1500;
                //tableContainer.setLayoutParams(params);
            } else {
                tableContainer.setVisibility(View.VISIBLE);
                totalLabel.setVisibility(View.VISIBLE);

                //ViewGroup.LayoutParams params =   tableContainer.getLayoutParams();
                //params.height = 1500;
                //tableContainer.setLayoutParams(params);
            }
            toggle = !toggle;
            card.requestLayout();
        }
    });

以下是包含标记的布局之一的示例。

    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    >
<TextView
    android:id="@+id/total_labeltv"
    android:layout_width="match_parent"
    android:text="total label"
    android:background="#C0c0c0"
    android:layout_height="wrap_content">

</TextView></RelativeLayout>

CardView动态包装其内容

解

1 个答案: