/*
* MIT License
*
* Copyright (c) 2016 Alibaba Group
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.alibaba.android.vlayout.layout;
import com.alibaba.android.vlayout.LayoutHelper;
import com.alibaba.android.vlayout.LayoutManagerHelper;
import com.alibaba.android.vlayout.OrientationHelperEx;
import com.alibaba.android.vlayout.R;
import com.alibaba.android.vlayout.VirtualLayoutManager;
import com.alibaba.android.vlayout.VirtualLayoutManager.LayoutStateWrapper;
import android.graphics.Rect;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
/**
* {@link com.alibaba.android.vlayout.LayoutHelper} that provides basic methods
*/
public abstract class BaseLayoutHelper extends MarginLayoutHelper {
private static final String TAG = "BaseLayoutHelper";
public static boolean DEBUG = false;
protected Rect mLayoutRegion = new Rect();
View mLayoutView;
int mBgColor;
float mAspectRatio = Float.NaN;
public BaseLayoutHelper() {
}
@Override
public boolean isFixLayout() {
return false;
}
public int getBgColor() {
return this.mBgColor;
}
/**
* Set backgroundColor for LayoutView
*
* @param bgColor
*/
public void setBgColor(int bgColor) {
this.mBgColor = bgColor;
}
public void setAspectRatio(float aspectRatio) {
this.mAspectRatio = aspectRatio;
}
public float getAspectRatio() {
return mAspectRatio;
}
private int mItemCount = 0;
/**
* The number of items in current layout
*
* @return the number of child views
*/
@Override
public int getItemCount() {
return mItemCount;
}
@Override
public void setItemCount(int itemCount) {
this.mItemCount = itemCount;
}
/**
* Retrieve next view and add it into layout, this is to make sure that view are added by order
*
* @param recycler recycler generate views
* @param layoutState current layout state
* @param helper helper to add views
* @param result chunk result to tell layoutManager whether layout process goes end
* @return next view to render, null if no more view available
*/
@Nullable
public final View nextView(RecyclerView.Recycler recycler, LayoutStateWrapper layoutState, LayoutManagerHelper helper, LayoutChunkResult result) {
View view = layoutState.next(recycler);
if (view == null) {
// if we are laying out views in scrap, this may return null which means there is
// no more items to layout.
if (DEBUG && !layoutState.hasScrapList()) {
throw new RuntimeException("received null view when unexpected");
}
// if there is no more views can be retrieved, this layout process is finished
result.mFinished = true;
return null;
}
helper.addChildView(layoutState, view);
return view;
}
@Override
public void beforeLayout(RecyclerView.Recycler recycler, RecyclerView.State state,
LayoutManagerHelper helper) {
if (DEBUG) {
Log.d(TAG, "call beforeLayout() on " + this.getClass().getSimpleName());
}
if (requireLayoutView()) {
if (mLayoutView != null) {
// TODO: recycle LayoutView
// helper.detachChildView(mLayoutView);
}
} else {
// if no layoutView is required, remove it
if (mLayoutView != null) {
if (mLayoutViewUnBindListener != null) {
mLayoutViewUnBindListener.onUnbind(mLayoutView, this);
}
helper.removeChildView(mLayoutView);
mLayoutView = null;
}
}
}
/**
* Tell whether the scrolled value is valid, if not, means it's a layout processing without scrolling
*
* @param scrolled value of how many pixels does scrolled
* @return true means during a scrolling process, false means during a layout process.
*/
protected boolean isValidScrolled(int scrolled) {
return scrolled != Integer.MAX_VALUE && scrolled != Integer.MIN_VALUE;
}
@Override
public void afterLayout(RecyclerView.Recycler recycler, RecyclerView.State state,
int startPosition, int endPosition, int scrolled,
LayoutManagerHelper helper) {
if (DEBUG) {
Log.d(TAG, "call afterLayout() on " + this.getClass().getSimpleName());
}
if (requireLayoutView()) {
if (isValidScrolled(scrolled) && mLayoutView != null) {
// initial layout do reset
mLayoutRegion.union(mLayoutView.getLeft(), mLayoutView.getTop(), mLayoutView.getRight(), mLayoutView.getBottom());
}
if (!mLayoutRegion.isEmpty()) {
if (isValidScrolled(scrolled)) {
if (helper.getOrientation() == VirtualLayoutManager.VERTICAL) {
mLayoutRegion.offset(0, -scrolled);
} else {
mLayoutRegion.offset(-scrolled, 0);
}
}
int contentWidth = helper.getContentWidth();
int contentHeight = helper.getContentHeight();
if (helper.getOrientation() == VirtualLayoutManager.VERTICAL ?
mLayoutRegion.intersects(0, -contentHeight / 4, contentWidth, contentHeight + contentHeight / 4) :
mLayoutRegion.intersects(-contentWidth / 4, 0, contentWidth + contentWidth / 4, contentHeight)) {
if (mLayoutView == null) {
mLayoutView = helper.generateLayoutView();
helper.addOffFlowView(mLayoutView, true);
}
//finally fix layoutRegion's height and with here to avoid visual blank
if (helper.getOrientation() == VirtualLayoutManager.VERTICAL) {
mLayoutRegion.left = helper.getPaddingLeft() + mMarginLeft;
mLayoutRegion.right = helper.getContentWidth() - helper.getPaddingRight() - mMarginRight;
} else {
mLayoutRegion.top = helper.getPaddingTop() + mMarginTop;
mLayoutRegion.bottom = helper.getContentHeight() - helper.getPaddingBottom() - mMarginBottom;
}
bindLayoutView(mLayoutView);
return;
} else {
mLayoutRegion.set(0, 0, 0, 0);
if (mLayoutView != null) {
mLayoutView.layout(0, 0, 0, 0);
}
}
}
}
if (mLayoutView != null) {
if (mLayoutViewUnBindListener != null) {
mLayoutViewUnBindListener.onUnbind(mLayoutView, this);
}
helper.removeChildView(mLayoutView);
mLayoutView = null;
}
}
@Override
public void adjustLayout(int startPosition, int endPosition, LayoutManagerHelper helper) {
if (requireLayoutView()) {
View refer = null;
Rect tempRect = new Rect();
final OrientationHelperEx orientationHelper = helper.getMainOrientationHelper();
for (int i = 0; i < helper.getChildCount(); i++) {
refer = helper.getChildAt(i);
int anchorPos = helper.getPosition(refer);
if (getRange().contains(anchorPos)) {
if (refer.getVisibility() == View.GONE) {
tempRect.setEmpty();
} else {
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams)
refer.getLayoutParams();
if (helper.getOrientation() == VirtualLayoutManager.VERTICAL) {
tempRect.union(helper.getDecoratedLeft(refer) - params.leftMargin,
orientationHelper.getDecoratedStart(refer),
helper.getDecoratedRight(refer) + params.rightMargin,
orientationHelper.getDecoratedEnd(refer));
} else {
tempRect.union(orientationHelper.getDecoratedStart(refer),
helper.getDecoratedTop(refer) - params.topMargin, orientationHelper.getDecoratedEnd(refer),
helper.getDecoratedBottom(refer) + params.bottomMargin);
}
}
}
}
if (!tempRect.isEmpty()) {
mLayoutRegion.set(tempRect.left - mPaddingLeft, tempRect.top - mPaddingTop,
tempRect.right + mPaddingRight, tempRect.bottom + mPaddingBottom);
} else {
mLayoutRegion.setEmpty();
}
if (mLayoutView != null) {
mLayoutView.layout(mLayoutRegion.left, mLayoutRegion.top, mLayoutRegion.right, mLayoutRegion.bottom);
}
}
}
/**
* Called when {@link com.alibaba.android.vlayout.LayoutHelper} get dropped
* Do default clean jobs defined by framework
*
* @param helper LayoutManagerHelper
*/
@Override
public final void clear(LayoutManagerHelper helper) {
// remove LayoutViews if there is one
if (mLayoutView != null) {
if (mLayoutViewUnBindListener != null) {
mLayoutViewUnBindListener.onUnbind(mLayoutView, this);
}
helper.removeChildView(mLayoutView);
mLayoutView = null;
}
// call user defined
onClear(helper);
}
/**
* Called when {@link com.alibaba.android.vlayout.LayoutHelper} get dropped, do clean custom jobs
*
* @param helper
*/
protected void onClear(LayoutManagerHelper helper) {
}
/**
* @return
*/
@Override
public boolean requireLayoutView() {
return mBgColor != 0 || mLayoutViewBindListener != null;
}
public abstract void layoutViews(RecyclerView.Recycler recycler, RecyclerView.State state,
LayoutStateWrapper layoutState, LayoutChunkResult result,
LayoutManagerHelper helper);
@Override
public void doLayout(RecyclerView.Recycler recycler, RecyclerView.State state, LayoutStateWrapper layoutState, LayoutChunkResult result, LayoutManagerHelper helper) {
layoutViews(recycler, state, layoutState, result, helper);
}
/**
* Helper function which do layout children and also update layoutRegion
* but it won't consider margin in layout, so you need take care of margin if you apply margin to your layoutView
*
* @param child child that will be laid
* @param left left position
* @param top top position
* @param right right position
* @param bottom bottom position
* @param helper layoutManagerHelper, help to lay child
*/
protected void layoutChildWithMargin(final View child, int left, int top, int right, int bottom, @NonNull LayoutManagerHelper helper) {
layoutChildWithMargin(child, left, top, right, bottom, helper, false);
}
protected void layoutChildWithMargin(final View child, int left, int top, int right, int bottom, @NonNull LayoutManagerHelper helper, boolean addLayoutRegionWithMargin) {
helper.layoutChildWithMargins(child, left, top, right, bottom);
if (requireLayoutView()) {
if (addLayoutRegionWithMargin) {
mLayoutRegion
.union(left - mPaddingLeft - mMarginLeft, top - mPaddingTop - mMarginTop,
right + mPaddingRight + mMarginRight,
bottom + mPaddingBottom + mMarginBottom);
} else {
mLayoutRegion.union(left - mPaddingLeft, top - mPaddingTop, right + mPaddingRight, bottom + mPaddingBottom);
}
}
}
/**
* Helper function which do layout children and also update layoutRegion
*
* @param child child that will be laid
* @param left left position
* @param top top position
* @param right right position
* @param bottom bottom position
* @param helper layoutManagerHelper, help to lay child
*/
protected void layoutChild(final View child, int left, int top, int right, int bottom, @NonNull LayoutManagerHelper helper) {
layoutChild(child, left, top, right, bottom, helper, false);
}
protected void layoutChild(final View child, int left, int top, int right, int bottom, @NonNull LayoutManagerHelper helper, boolean addLayoutRegionWithMargin) {
helper.layoutChild(child, left, top, right, bottom);
if (requireLayoutView()) {
if (addLayoutRegionWithMargin) {
mLayoutRegion
.union(left - mPaddingLeft - mMarginLeft, top - mPaddingTop - mMarginTop,
right + mPaddingRight + mMarginRight,
bottom + mPaddingBottom + mMarginBottom);
} else {
mLayoutRegion.union(left - mPaddingLeft, top - mPaddingTop, right + mPaddingRight, bottom + mPaddingBottom);
}
}
}
/**
* Listener to handle LayoutViews, like bgImage
*/
public interface LayoutViewBindListener {
void onBind(View layoutView, BaseLayoutHelper baseLayoutHelper);
}
/**
* Listener to handle LayoutViews, like bgImage
*/
public interface LayoutViewUnBindListener {
void onUnbind(View layoutView, BaseLayoutHelper baseLayoutHelper);
}
public interface LayoutViewHelper {
/**
* Implement it by maintaining a map between layoutView and image url or setting a unique tag to view. It's up to your choice.
* @param layoutView view ready to be binded with an image
* * @param id layoutView's identifier
*/
void onBindViewSuccess(View layoutView, String id);
}
private LayoutViewUnBindListener mLayoutViewUnBindListener;
private LayoutViewBindListener mLayoutViewBindListener;
/**
* Helper to decide whether call {@link LayoutViewBindListener#onBind(View, BaseLayoutHelper)}.
* Here is a performance issue: {@link LayoutViewBindListener#onBind(View, BaseLayoutHelper)} is called during layout phase,
* when binding image to it would cause view tree to relayout, then the same {@link LayoutViewBindListener#onBind(View, BaseLayoutHelper)} would be called.
* User should provide enough information to tell LayoutHelper whether image has been bind success.
* If image has been successfully binded , no more dead loop happens.
*
* Of course you can handle this logic by yourself and ignore this helper.
*/
public static class DefaultLayoutViewHelper implements LayoutViewBindListener, LayoutViewUnBindListener, LayoutViewHelper {
private final LayoutViewBindListener mLayoutViewBindListener;
private final LayoutViewUnBindListener mLayoutViewUnBindListener;
public DefaultLayoutViewHelper(
LayoutViewBindListener layoutViewBindListener,
LayoutViewUnBindListener layoutViewUnBindListener) {
mLayoutViewBindListener = layoutViewBindListener;
mLayoutViewUnBindListener = layoutViewUnBindListener;
}
@Override
public void onBindViewSuccess(View layoutView, String id) {
layoutView.setTag(R.id.tag_layout_helper_bg, id);
}
@Override
public void onBind(View layoutView, BaseLayoutHelper baseLayoutHelper) {
if (layoutView.getTag(R.id.tag_layout_helper_bg) == null) {
if (mLayoutViewBindListener != null) {
mLayoutViewBindListener.onBind(layoutView, baseLayoutHelper);
}
}
}
@Override
public void onUnbind(View layoutView, BaseLayoutHelper baseLayoutHelper) {
if (mLayoutViewUnBindListener != null) {
mLayoutViewUnBindListener.onUnbind(layoutView, baseLayoutHelper);
}
layoutView.setTag(R.id.tag_layout_helper_bg, null);
}
}
public void setLayoutViewHelper(DefaultLayoutViewHelper layoutViewHelper) {
mLayoutViewBindListener = layoutViewHelper;
mLayoutViewUnBindListener = layoutViewHelper;
}
/**
* Better to use {@link #setLayoutViewHelper(DefaultLayoutViewHelper)}
* @param bindListener
*/
public void setLayoutViewBindListener(LayoutViewBindListener bindListener) {
mLayoutViewBindListener = bindListener;
}
/**
* Better to use {@link #setLayoutViewHelper(DefaultLayoutViewHelper)}
* @param layoutViewUnBindListener
*/
public void setLayoutViewUnBindListener(
LayoutViewUnBindListener layoutViewUnBindListener) {
mLayoutViewUnBindListener = layoutViewUnBindListener;
}
@Override
public void bindLayoutView(@NonNull final View layoutView) {
layoutView.measure(View.MeasureSpec.makeMeasureSpec(mLayoutRegion.width(), View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(mLayoutRegion.height(), View.MeasureSpec.EXACTLY));
layoutView.layout(mLayoutRegion.left, mLayoutRegion.top, mLayoutRegion.right, mLayoutRegion.bottom);
layoutView.setBackgroundColor(mBgColor);
if (mLayoutViewBindListener != null) {
mLayoutViewBindListener.onBind(layoutView, this);
}
// reset region rectangle
mLayoutRegion.set(0, 0, 0, 0);
}
protected void handleStateOnResult(LayoutChunkResult result, View view) {
if (view == null) {
return;
}
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
// Consume the available space if the view is not removed OR changed
if (params.isItemRemoved() || params.isItemChanged()) {
result.mIgnoreConsumed = true;
}
// used when search a focusable view
result.mFocusable = result.mFocusable || view.isFocusable();
}
/**
* Helper methods to handle focus states for views
* @param result
* @param views
*/
protected void handleStateOnResult(LayoutChunkResult result, View[] views) {
if (views == null) return;
for (int i = 0; i < views.length; i++) {
View view = views[i];
if (view == null) {
continue;
}
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
// Consume the available space if the view is not removed OR changed
if (params.isItemRemoved() || params.isItemChanged()) {
result.mIgnoreConsumed = true;
}
// used when search a focusable view
result.mFocusable = result.mFocusable || view.isFocusable();
if (result.mFocusable && result.mIgnoreConsumed) {
break;
}
}
}
protected int computeStartSpace(LayoutManagerHelper helper, boolean layoutInVertical, boolean isLayoutEnd, boolean isOverLapMargin) {
int startSpace = 0;
LayoutHelper lastLayoutHelper = null;
if (helper instanceof VirtualLayoutManager) {
lastLayoutHelper = ((VirtualLayoutManager) helper).findNeighbourNonfixLayoutHelper(this, isLayoutEnd);
}
MarginLayoutHelper lastMarginLayoutHelper = null;
if (lastLayoutHelper != null && lastLayoutHelper instanceof MarginLayoutHelper) {
lastMarginLayoutHelper = (MarginLayoutHelper) lastLayoutHelper;
}
if (lastLayoutHelper == this)
return 0;
if (!isOverLapMargin) {
startSpace = layoutInVertical ? mMarginTop + mPaddingTop : mMarginLeft + mPaddingLeft;
} else {
int offset = 0;
if (lastMarginLayoutHelper == null) {
offset = layoutInVertical ? mMarginTop + mPaddingTop : mMarginLeft + mPaddingLeft;
} else {
offset = layoutInVertical
? (isLayoutEnd ? calGap(lastMarginLayoutHelper.mMarginBottom, mMarginTop) : calGap(lastMarginLayoutHelper.mMarginTop, mMarginBottom))
: (isLayoutEnd ? calGap(lastMarginLayoutHelper.mMarginRight, mMarginLeft) : calGap(lastMarginLayoutHelper.mMarginLeft, mMarginRight));
}
//Log.e("huang", "computeStartSpace offset: " + offset + ", isLayoutEnd: " + isLayoutEnd + ", " + this);
startSpace += layoutInVertical
? (isLayoutEnd ? mPaddingTop : mPaddingBottom)
: (isLayoutEnd ? mPaddingLeft : mPaddingRight);
startSpace += offset;
}
return startSpace;
}
protected int computeEndSpace(LayoutManagerHelper helper, boolean layoutInVertical, boolean isLayoutEnd, boolean isOverLapMargin) {
int endSpace = layoutInVertical
? mMarginBottom + mPaddingBottom : mMarginLeft + mPaddingLeft;
//Log.e("huang", "computeEndSpace offset: " + endSpace + ", isLayoutEnd: " + isLayoutEnd + ", " + this);
//Log.e("huang", "===================\n\n");
return endSpace;
}
private int calGap(int gap, int currGap) {
if (gap < currGap) {
return currGap - gap;
} else {
return 0;
}
}
}
