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安卓app开发中解决recycleview 和 scollview 嵌套 问题

app开发问题,郑州app开发2018-03-07637

有时候想要recycleview 和 scollview 嵌套 并且全部展开recycleview,这样的app技术无疑是很多人头疼的,那么下面郑州app开发就来详细的讲解一下。

郑州app开发

但是会发现 简单的嵌套后 recycleview不能滑动 或者无法看到展开的全部内容

下面郑州app开发小编为大家附上解决问题的代码

经过查阅相关内容发现在设置recycleview。setLayoutManager可以解决这个问题

下面是manager的代码

public class FullyLinearLayoutManager extends 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();

public FullyLinearLayoutManager(Context context) {

super(context);

this.view = null;

}

public FullyLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {

super(context, orientation, reverseLayout);

this.view = null;

}

public FullyLinearLayoutManager(RecyclerView view) {

super(view.getContext());

this.view = view;

this.overScrollMode = ViewCompat.getOverScrollMode(view);

}

public FullyLinearLayoutManager(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();

// 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) {

}

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) {

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;

}

}

以上信息由郑州app开发公司燚轩科技整理发布。


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