RecyclerView通用分割線

摘要： 使用方式 listContent.addItemDecoration( Divider.builder(). color(getResources().getColor(R.color.bgDefaul...

使用方式

listContent.addItemDecoration(
Divider.builder().
color(getResources().getColor(R.color.bgDefaultColor))
.height(3)
.build()
);

使用範圍

GridLayoutManager;LinearLayoutManager;StaggeredGridLayoutManager;

程式碼來源

來自網路，已忘記開源作者

原始碼貼上

/**
 * 描述: RecyclerView通用分割線
 * @author Smile
 */
@SuppressWarnings("unused")
public class Divider extends RecyclerView.ItemDecoration {

private Drawable dividerDrawable;
private final int DEFAULT_LINE_WIDTH = 10;
private final int DEFAULT_LINE_HEIGHT = 20;

private int lineWidth = DEFAULT_LINE_WIDTH;// 線的寬度
private int lineHeight = DEFAULT_LINE_HEIGHT;// 線的高度
private int headerCount = 0;// 頭的數量
private int footerCount = 0;// 尾的數量

Divider() {
dividerDrawable = new ColorDrawable(Color.GRAY);
}

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (isSkipDraw(parent, view))
return;// 跳過，不繪製
int currentPosition = parent.getChildAdapterPosition(view);
int spanCount = getSpanCount(parent);// 水平個數，線性佈局為-1
int childCount = parent.getAdapter().getItemCount();// 總個數
int right = lineWidth;
int bottom = lineHeight;
if (isNotDrawBottom(view, parent, currentPosition, spanCount, childCount))
// 如果是最後一行，則不需要繪製底部
bottom = 0;
if (isNotDrawRight(view, parent, currentPosition, spanCount, childCount))
// 如果是最後一列，則不需要繪製右邊
right = 0;
outRect.set(0, 0, right, bottom);
}


@Override
public void onDraw(Canvas canvas, RecyclerView parent, RecyclerView.State state) {
drawHorizontal(canvas, parent, lineWidth, lineHeight);
drawVertical(canvas, parent, lineWidth, lineHeight);
}

/**
* 是否不繪製右部
*
* @param view當前的view，StaggeredGridLayoutManager 用
* @param parentRecyclerView
* @param currentPosition 當前的位置，GridLayoutManager、LinearLayoutManager用
* @param spanCount列數
* @param adapterCountadapter的總數
* @return 返回true代表不繪製右部，返回false，代表繪製右部
*/
private boolean isNotDrawRight(View view, RecyclerView parent, int currentPosition, int spanCount, int adapterCount) {
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
// GridLayoutManager
currentPosition -= getHeaderCount();// 去掉頭的數量
adapterCount -= getHeaderCount() + getFooterCount();// 去掉頭、尾的數量
// 判斷最後一個是否繪製
if (((GridLayoutManager) layoutManager).getOrientation() == LinearLayoutManager.VERTICAL) {
// 垂直，判斷是否是最後一列
return (currentPosition + 1) % spanCount == 0;
} else {
// 水平，判斷是不是最後的
if (adapterCount % spanCount == 0)
return currentPosition >= adapterCount - spanCount;
else
return currentPosition >= adapterCount - adapterCount % spanCount;
}
} else if (layoutManager instanceof LinearLayoutManager) {
// LinearLayoutManager
// 判斷最後一個是否繪製，垂直，不繪製右邊，直接返回true,水平，判斷，是否是最後一個
return ((LinearLayoutManager) layoutManager).getOrientation() == LinearLayout.VERTICAL || currentPosition == adapterCount - getFooterCount() - 1;
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
// 判斷最後一個是否繪製，垂直，判斷是否是最後一列，是返回true，水平，都顯示，返回false
StaggeredGridLayoutManager.LayoutParams lp = (StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams();
return ((StaggeredGridLayoutManager) layoutManager).getOrientation() == StaggeredGridLayoutManager.VERTICAL && (lp.getSpanIndex() + 1) % spanCount == 0;
}
return false;
}

/**
* 是否不繪製底部
*
* @param view當前的view，StaggeredGridLayoutManager 用
* @param parentRecyclerView
* @param currentPosition 當前的位置，GridLayoutManager、LinearLayoutManager用
* @param spanCount列數
* @param adapterCountadapter的總數
* @return 返回true代表不繪製底部，返回false，代表繪製底部
*/
private boolean isNotDrawBottom(View view, RecyclerView parent, int currentPosition, int spanCount, int adapterCount) {
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
// GridLayoutManager
currentPosition -= getHeaderCount();// 去掉頭的數量
adapterCount -= getHeaderCount() + getFooterCount();// 去掉頭、尾的數量
// 判斷最後一個是否繪製
if (((GridLayoutManager) layoutManager).getOrientation() == LinearLayoutManager.VERTICAL) {
// 垂直，判斷是不是最後的
if (adapterCount % spanCount == 0)
return currentPosition >= adapterCount - spanCount;
else
return currentPosition >= adapterCount - adapterCount % spanCount;
} else {
// 水平，判斷是不是最後一列
return (currentPosition + 1) % spanCount == 0;
}
} else if (layoutManager instanceof LinearLayoutManager) {
// LinearLayoutManager
// 判斷最後一個是否繪製，垂直，判斷是否是最後一行,水平，直接返回true，不繪製底部
return ((LinearLayoutManager) layoutManager).getOrientation() != LinearLayout.VERTICAL || currentPosition == adapterCount - getFooterCount() - 1;
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
// StaggeredGridLayoutManager
// 判斷最後一個是否繪製，垂直，都顯示，返回false， 水平，判斷是否是最後一列，是返回true
StaggeredGridLayoutManager.LayoutParams lp = (StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams();
return ((StaggeredGridLayoutManager) layoutManager).getOrientation() != StaggeredGridLayoutManager.VERTICAL && (lp.getSpanIndex() + 1) % spanCount == 0;
}
return false;
}

/**
* 繪製水平線
*
* @param canvas畫布
* @param parentRecyclerView
* @param lineWidth線寬
* @param lineHeight 線高
*/
private void drawHorizontal(Canvas canvas, RecyclerView parent, int lineWidth, int lineHeight) {
boolean isDrawDoubleLine = false;
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof StaggeredGridLayoutManager && ((StaggeredGridLayoutManager) layoutManager).getOrientation() == StaggeredGridLayoutManager.HORIZONTAL)
// 繪製雙線
isDrawDoubleLine = true;
canvas.save();
int spanCount = getSpanCount(parent);// 水平個數，線性佈局為-1
int childCount = parent.getChildCount();// 顯示的個數
int adapterCount = parent.getAdapter().getItemCount();// 總個數
if (parent.getClipToPadding()) {
canvas.clipRect(parent.getPaddingLeft(), parent.getPaddingTop(),
parent.getWidth() - parent.getPaddingRight(),
parent.getHeight() - parent.getPaddingBottom());
}

for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
int currentPosition = parent.getChildAdapterPosition(child);
if (isSkipDraw(parent, child))
// 跳過，直接返回
continue;
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (!isNotDrawBottom(child, parent, currentPosition, spanCount, adapterCount)) {
// 繪製底部
int bottomLineWidth = isNotDrawRight(child, parent, currentPosition, spanCount, adapterCount) ? 0 : lineWidth;// 不繪製右部，公共區域不繪製
// 繪製下線
final int downLeft = child.getLeft() - params.leftMargin;
final int downTop = child.getBottom() + params.bottomMargin;
final int downRight = child.getRight() + params.rightMargin + bottomLineWidth;// 公共區域繪製
final int downBottom = downTop + lineHeight;
dividerDrawable.setBounds(downLeft, downTop, downRight, downBottom);
dividerDrawable.draw(canvas);
}
// 判斷是否繪製雙線
if (isDrawDoubleLine && isStaggeredGridNotFirstView(child, spanCount)) {
// 繪製上線
final int upLeft = child.getLeft() - params.leftMargin;
final int upTop = child.getTop() + params.topMargin - lineHeight;
final int upRight = child.getRight() + params.rightMargin + lineWidth;// 公共區域繪製
final int upBottom = upTop + lineHeight;
dividerDrawable.setBounds(upLeft, upTop, upRight, upBottom);
dividerDrawable.draw(canvas);
}
}
canvas.restore();
}

/**
* 繪製垂直線
*
* @param canvas畫布
* @param parentRecyclerView
* @param lineWidth線寬
* @param lineHeight 線高
*/
private void drawVertical(Canvas canvas, RecyclerView parent, int lineWidth, int lineHeight) {
boolean isDrawDoubleLine = false;
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof StaggeredGridLayoutManager && ((StaggeredGridLayoutManager) layoutManager).getOrientation() == StaggeredGridLayoutManager.VERTICAL)
// 繪製雙線
isDrawDoubleLine = true;
canvas.save();
if (parent.getClipToPadding()) {
canvas.clipRect(parent.getPaddingLeft(), parent.getPaddingTop(),
parent.getWidth() - parent.getPaddingRight(),
parent.getHeight() - parent.getPaddingBottom());
}
int spanCount = getSpanCount(parent);// 水平個數，線性佈局為-1
int childCount = parent.getChildCount();
int adapterCount = parent.getAdapter().getItemCount();// 總個數
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
int currentPosition = parent.getChildAdapterPosition(child);
if (isSkipDraw(parent, child))
// 跳過、不繪製右部，直接返回
continue;
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (!isNotDrawRight(child, parent, currentPosition, spanCount, adapterCount)) {
// 不繪製右邊
if (isNotDrawBottom(child, parent, currentPosition, spanCount, adapterCount))
// 不繪製底部，公共區域不繪製
lineHeight = 0;
final int left = child.getRight() + params.rightMargin;
final int top = child.getTop() - params.topMargin;
final int right = left + lineWidth;
final int bottom = child.getBottom() + params.bottomMargin + lineHeight;// 公共區域水平繪製
dividerDrawable.setBounds(left, top, right, bottom);
dividerDrawable.draw(canvas);
}
// 判斷是否繪製雙線
if (isDrawDoubleLine && isStaggeredGridNotFirstView(child, spanCount)) {
// 繪製左線
final int left = child.getLeft() + params.leftMargin - lineWidth;
final int top = child.getTop() - params.topMargin;
final int right = left + lineWidth;
final int bottom = child.getBottom() + params.bottomMargin + lineHeight;// 公共區域水平繪製
dividerDrawable.setBounds(left, top, right, bottom);
dividerDrawable.draw(canvas);
}
}
canvas.restore();
}

/**
* 是否是StaggeredGridLayoutManager的中間的view
*
* @param view測定的view
* @param spanCount 列數
*/
private boolean isStaggeredGridNotFirstView(View view, int spanCount) {
StaggeredGridLayoutManager.LayoutParams lp = (StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams();
return lp.getSpanIndex() != 0;
}

/**
* 是否跳過繪畫
*
* @param parent RecyclerView
* @param view當前View
*/
private boolean isSkipDraw(RecyclerView parent, View view) {
int currentPosition = parent.getChildAdapterPosition(view);// 當前item總位置
int adapterCount = parent.getAdapter().getItemCount();
return currentPosition < getHeaderCount() || currentPosition >= adapterCount - getFooterCount();
}

/**
* 獲取列數
*
* @param parent RecyclerView
* @return 列數
*/
private int getSpanCount(RecyclerView parent) {
// 列數
int spanCount = -1;
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
} else if (layoutManager instanceof LinearLayoutManager) {
spanCount = 1;
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
spanCount = ((StaggeredGridLayoutManager) layoutManager).getSpanCount();
}
return spanCount;
}

/**
* 獲取線寬
*/
public int getLineWidth() {
return lineWidth;
}

/**
* 設定線寬
*/
public void setLineWidth(int lineWidth) {
this.lineWidth = lineWidth;
}

/**
* 獲取線高
*/
public int getLineHeight() {
return lineHeight;
}

/**
* 設定線高
*/
public void setLineHeight(int lineHeight) {
this.lineHeight = lineHeight;
}

/**
* 獲取線Drawable
*/
public Drawable getDividerDrawable() {
return dividerDrawable;
}

/**
* 設定線Drawable，和setLineColor()二選一
*/
public void setDividerDrawable(Drawable dividerDrawable) {
this.dividerDrawable = dividerDrawable;
}

/**
* 設定線顏色，和setDividerDrawable()二選一
*/
public void setLineColor(int lineColor) {
this.dividerDrawable = new ColorDrawable(lineColor);
}

/**
* 獲取頭數量
*/
private int getHeaderCount() {
return headerCount;
}

/**
* 設定頭數量，即頭部跳過繪製
*/
public void setHeaderCount(int headerCount) {
this.headerCount = headerCount;
}

/**
* 獲取尾數量
*/
private int getFooterCount() {
return footerCount;
}

/**
* 設定尾數量，即尾部跳過繪製
*/
public void setFooterCount(int footerCount) {
this.footerCount = footerCount;
}

/**
* Divider的構建者
*/
public static Builder builder() {
return new Builder();
}

public static class Builder {

private final Divider divider;

Builder() {
divider = new Divider();
}

/**
* 設定線寬
*/
public Builder width(int lineWidth) {
divider.setLineWidth(lineWidth);
return this;
}

/**
* 設定線高
*/
public Builder height(int lineHeight) {
divider.setLineHeight(lineHeight);
return this;
}

/**
* 同時設定線寬、線高
*/
public Builder widthAndHeight(int lineSize) {
divider.setLineWidth(lineSize);
divider.setLineHeight(lineSize);
return this;
}

/**
* 設定線顏色，和drawable二選一
*/
public Builder color(int lineColor) {
divider.setLineColor(lineColor);
return this;
}

/**
* 設定線背景，和color二選一
*/
public Builder drawable(Drawable dividerDrawable) {
divider.setDividerDrawable(dividerDrawable);
return this;
}

/**
* 設定頭的數量
*/
public Builder headerCount(int headerCount) {
divider.setHeaderCount(headerCount);
return this;
}

/**
* 設定尾的數量
*/
public Builder footerCount(int footerCount) {
divider.setFooterCount(footerCount);
return this;
}

/**
* 返回Divider
*/
public Divider build() {
return this.divider;
}

}
}