RecyclerView 之ItemDecoration分隔线
RecyclerView 之ItemDecoration悬浮分隔线
RecyclerView 之ItemDecoration分隔线+悬浮分隔线
前两节已经实现了RecyclerView的分隔线和悬浮分隔线，那么：
RecyclerView的 addItemDecoration可以添加多个分隔线，那么就可以通过添加分隔线和悬浮分隔线来实现一些简单的联系人列表、城市列表之类的效果了。
但是：
- 能不能分隔线和悬浮分隔线放在一起，实现更方便的控制呢；
- 这里的悬浮分隔线只能是文字，如果是复杂的View呢，或是文字和View混合呢；
- 如果悬浮分隔线是一个View，那悬浮分隔线的高度是否能各不相同呢；
混合分隔
又来抛砖了：
package com.test.wrapper.indexList;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.SparseArray;
import android.view.View;
import android.view.ViewGroup;
import java.lang.ref.WeakReference;
/**
* RecyclerView 分隔线
*/
public class StickDecoration extends RecyclerView.ItemDecoration {
/**
* 悬浮类型为文字
*/
private final static int STICK_TYPE_TEXT = 1;
/**
* 悬浮类型为View
*/
private final static int STICK_TYPE_VIEW = 2;
/**
* 分隔线 颜色、高度、左Margin、右Margin
*/
private Paint mDividerPaint;
private int mDividerColor = Color.parseColor("#dbdbdb");
private int mDividerHeight = 1;
private int mDividerLeftMargin = 0;
private int mDividerRightMargin = 0;
/**
* 悬浮文案 颜色、字体颜色、字体大小、左Margin
*/
private Paint mStickPaint;
private int mStickColor = Color.parseColor("#dbdbdb");
private int mStickTextColor = Color.parseColor("#333333");
private float mStickTextSize = 40f;
private int mStickTextLeftMargin = 100;
private Paint mStickTextPaint;
/**
* 悬浮文案 文案区域框
*/
private Rect mStickTextBounds;
/**
* 悬浮文案 高度
*/
private int mStickHeight = 100;
/**
* RecyclerView 首部偏移量，前mOffsetStart个item不展示分隔线
*/
private int mOffsetStart = 1;
/**
* RecyclerView 尾部偏移量，后mOffsetEnd个item不展示分隔线
*/
private int mOffsetEnd = 1;
/**
* 悬浮文案缓存
*/
private SparseArray<String> mStickText = new SparseArray<>();
/**
* 悬浮View缓存
*/
private SparseArray<WeakReference<View>> mStickView = new SparseArray<>();
public StickDecoration() {
this.mDividerPaint = new Paint();
//分隔线画笔
mDividerPaint.setColor(mDividerColor);
//抗锯齿
mDividerPaint.setAntiAlias(true);
//抗抖动
mDividerPaint.setDither(true);
//悬浮分隔
mStickPaint = new Paint();
mStickPaint.setAntiAlias(true);
mStickPaint.setDither(true);
mStickPaint.setColor(mStickColor);
//悬浮分隔文字
mStickTextPaint = new TextPaint();
mStickTextPaint.setAntiAlias(true);
mStickTextPaint.setDither(true);
//文字加粗
mStickTextPaint.setTypeface(Typeface.DEFAULT_BOLD);
mStickTextPaint.setColor(mStickTextColor);
mStickTextPaint.setTextSize(mStickTextSize);
//悬浮分隔区域
mStickTextBounds = new Rect();
}
/**
* 用以设置ItemView的内嵌偏移长度（inset）
*
* @param outRect Rect
* @param view View
* @param parent RecyclerView
* @param state RecyclerView.State
*/
@Override
public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
//获取子View在RecyclerView中位置
int positionInRecycler = parent.getChildAdapterPosition(view);
//判断当前位置是否需要 分隔View 或 分隔线 或 悬浮分隔
View pinnedView = getStickView(positionInRecycler, parent);
if (pinnedView != null) {
pinnedView.measure(
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
outRect.top = pinnedView.getMeasuredHeight();
} else if (isHasStickDivider(parent, positionInRecycler)) {
outRect.top = mStickHeight;
} else if (isHasDivider(parent, positionInRecycler)) {
outRect.top = mDividerHeight;
}
}
/**
* 在子视图上设置绘制范围，并绘制内容
* 先于ItemView绘制, 所以绘制图层在ItemView以下，所以如果绘制区域与ItemView区域相重叠，会被遮挡
*
* @param c Canvas
* @param parent RecyclerView
* @param state RecyclerView.State
*/
@Override
public void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.onDraw(c, parent, state);
//不需绘制分隔线
if (mDividerHeight < 0) {
return;
}
//获取RecyclerView的Child view的个数
int childCount = parent.getChildCount();
//如果子ItemView数量小于偏移数量,则返回
if (parent.getChildCount() <= mOffsetStart + mOffsetEnd) {
return;
}
//遍历每个Item，分别获取它们的位置信息，然后再绘制对应的分割线
for (int i = 0; i < childCount; i++) {
View childView = parent.getChildAt(i);
if (isHasDivider(parent, childView)) {
//绘制Divider宽度与ItemView宽度一致
drawDivider(c, childView.getLeft() + mDividerLeftMargin,
childView.getTop() - mDividerHeight,
childView.getRight() - mDividerRightMargin,
childView.getTop());
}
}
}
/**
* 同样是绘制内容，但与onDraw() 的区别是：绘制在图层的最上层，会覆盖底层的视图
*
* @param c Canvas
* @param parent RecyclerView
* @param state RecyclerView.State
*/
@Override
public void onDrawOver(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.onDrawOver(c, parent, state);
//如果子ItemView数量小于偏移数量,则返回
if (parent.getChildCount() <= mOffsetStart + mOffsetEnd) {
return;
}
//当前页面中的悬浮分隔的计数器
int stickIndex = 0;
//parent.getChildCount为当前页面中可见的Child view的个数
for (int i = 0; i < parent.getChildCount(); i++) {
//获取页面中View在RecyclerView中的位置
final View childView = parent.getChildAt(i);
int positionInRecycler = parent.getChildAdapterPosition(childView);
//悬浮分隔视图：若为空，则不展示
View stickView = getStickView(positionInRecycler, parent);
if (stickView != null) {
if (childView.getTop() <= stickView.getMeasuredHeight()) {
//若有悬浮分隔的childView顶部 <= 悬浮分隔的高度, 则悬浮顶部
drawStickView(c, 0, 0, parent.getRight(), stickView.getMeasuredHeight(), stickView);
} else {
//若有悬浮分隔的childView顶部 > 悬浮分隔的高度, 则绘制该View的悬浮分隔线
drawStickView(c, 0, childView.getTop() - stickView.getMeasuredHeight(), parent.getRight(), childView.getTop(), stickView);
//如果是该页面的第一个悬浮分割线，则寻找是否有上一个悬浮分隔
drawOverLastStick(c, parent, childView, positionInRecycler, stickIndex, stickView.getMeasuredHeight());
}
stickIndex++;
continue;
}
//悬浮分隔文案：若为空，则不展示
String stickText = getStickText(positionInRecycler, parent);
if (!TextUtils.isEmpty(stickText)) {
if (childView.getTop() <= mStickHeight) {
//若有悬浮分隔的childView顶部 <= 悬浮分隔的高度, 则悬浮顶部
drawStickText(c, 0, 0, parent.getRight(), mStickHeight, stickText);
} else {
//若有悬浮分隔的childView顶部 > 悬浮分隔的高度, 则绘制该View的悬浮分隔线
drawStickText(c, 0, childView.getTop() - mStickHeight, parent.getRight(), childView.getTop(), stickText);
//如果是该页面的第一个悬浮分割线，则寻找是否有上一个悬浮分隔
drawOverLastStick(c, parent, childView, positionInRecycler, stickIndex, mStickHeight);
}
stickIndex++;
}
}
//若当前页面中没有ChildView拥有悬浮分隔线，则寻找上一个悬浮分隔线，并悬浮顶部
if (stickIndex == 0) {
int positionInRecycler = parent.getChildAdapterPosition(parent.getChildAt(0));
//上一个悬浮分隔的类型是视图还是文案
int floatingStickType = getLastStickType(positionInRecycler, parent);
if (floatingStickType == STICK_TYPE_VIEW) {
//上一个悬浮视图
View lastPinnedView = getLastStickView(positionInRecycler, parent);
if (lastPinnedView != null) {
drawStickView(c, 0, 0, parent.getRight(), lastPinnedView.getMeasuredHeight(), lastPinnedView);
return;
}
} else if (floatingStickType == STICK_TYPE_TEXT) {
//上一个悬浮文案
String lastStickText = getLastStickText(positionInRecycler, parent);
if (!TextUtils.isEmpty(lastStickText)) {
drawStickText(c, 0, 0, parent.getRight(), mStickHeight, lastStickText);
}
}
}
}
private void drawOverLastStick(Canvas c, RecyclerView parent, View childView, int positionInRecycler, int stickIndex, int currentStickHeight) {
//如果是该页面的第一个悬浮分割线，则寻找是否有上一个悬浮分隔，若有，则上一个悬浮分隔正在顶部悬浮
if (stickIndex == 0) {
//上一个悬浮分隔的类型是视图还是文案
int floatingStickType = getLastStickType(positionInRecycler, parent);
if (floatingStickType == STICK_TYPE_VIEW) {
//若有上一个悬浮分隔，则悬浮顶部
View lastPinnedView = getLastStickView(positionInRecycler, parent);
if (lastPinnedView != null) {
//若该页面的第一个悬浮分割线的底部 < 悬浮分隔高度的2倍（悬浮顶部 + 该childView的悬浮分隔，则变换悬浮顶部的位置，实现向上推动的效果
if (childView.getTop() < lastPinnedView.getMeasuredHeight() + currentStickHeight) {
drawStickView(c, 0,
childView.getTop() - currentStickHeight - lastPinnedView.getMeasuredHeight(),
parent.getRight(),
childView.getTop() - currentStickHeight, lastPinnedView);
} else {
drawStickView(c, 0, 0, parent.getRight(), lastPinnedView.getMeasuredHeight(), lastPinnedView);
}
}
} else if (floatingStickType == STICK_TYPE_TEXT) {
//若有上一个悬浮分隔，则悬浮顶部
String lastStickText = getLastStickText(positionInRecycler, parent);
if (!TextUtils.isEmpty(lastStickText)) {
//若该页面的第一个悬浮分割线的底部 < 悬浮分隔高度的2倍（悬浮顶部 + 该childView的悬浮分隔，则变换悬浮顶部的位置，实现向上推动的效果
if (childView.getTop() < mStickHeight + currentStickHeight) {
drawStickText(c, 0,
childView.getTop() - mStickHeight - currentStickHeight,
parent.getRight(),
childView.getTop() - currentStickHeight, lastStickText);
} else {
drawStickText(c, 0, 0, parent.getRight(), mStickHeight, lastStickText);
}
}
}
}
}
//绘制分隔线
private void drawDivider(Canvas c, float left, float top, float right, float bottom) {
// 通过Canvas绘制矩形（分割线）
c.drawRect(left, top, right, bottom, mDividerPaint);
}
//某个ItemView是否有分隔线
private boolean isHasDivider(RecyclerView parent, View childView) {
return isHasDivider(parent, parent.getChildAdapterPosition(childView));
}
//某个ItemView是否有悬浮分隔线
private boolean isHasStickDivider(RecyclerView parent, View childView) {
int position = parent.getChildAdapterPosition(childView);
return !TextUtils.isEmpty(getStickText(position, parent));
}
/**
* 某位置是否有分隔线
* 子类可覆盖
*
* @param parent RecyclerView
* @param positionInRecycler RecyclerView中位置
* @return boolean
*/
protected boolean isHasDivider(RecyclerView parent, int positionInRecycler) {
if (positionInRecycler <= mOffsetStart) {
return false;
}
if (parent.getAdapter() != null) {
if (positionInRecycler > parent.getAdapter().getItemCount() - mOffsetEnd - mOffsetStart) {
return false;
}
}
return true;
}
/**
* 某位置是否有悬浮分隔
* 子类可覆盖
*
* @param parent RecyclerView
* @param positionInRecycler RecyclerView中位置
* @return boolean
*/
protected boolean isHasStickDivider(RecyclerView parent, int positionInRecycler) {
return !TextUtils.isEmpty(getStickText(positionInRecycler, parent));
}
//悬浮分隔文案
protected String getStickText(int positionInRecycler, @NonNull RecyclerView parent) {
String stickText = mStickText.get(positionInRecycler);
if (TextUtils.isEmpty(stickText)) {
stickText = onCreateStickText(positionInRecycler, parent);
}
return stickText;
}
//绘制悬浮分隔以及文案
private void drawStickText(Canvas c, float left, float top, float right, float bottom, String text) {
c.drawRect(left, top, right, bottom, mStickPaint);
mStickTextPaint.getTextBounds(text, 0, text.length(), mStickTextBounds);
c.drawText(text, left + mStickTextLeftMargin, bottom - mStickHeight / 2f + mStickTextBounds.height() / 2f, mStickTextPaint);
}
//获取某位置的上一个悬浮分隔文案
private String getLastStickText(int positionInRecycler, RecyclerView parent) {
String lastStickText = "";
for (int i = positionInRecycler - 1; i >= 0; i--) {
lastStickText = getStickText(i, parent);
if (!TextUtils.isEmpty(lastStickText)) {
break;
}
}
return lastStickText;
}
/**
* 悬浮分隔文案
* 子类可覆盖
*
* @param positionInRecycler RecyclerView中位置
* @param parent RecyclerView
* @return String
*/
protected String onCreateStickText(int positionInRecycler, @NonNull RecyclerView parent) {
return null;
}
//绘制悬浮分隔以及View
private void drawStickView(Canvas c, float left, float top, float right, float bottom, View stickView) {
if (stickView.getDrawingCache() != null) {
c.drawBitmap(stickView.getDrawingCache(), left, top, null);
}
}
private int getLastStickType(int positionInRecycler, @NonNull RecyclerView parent) {
int type = 0;
for (int i = positionInRecycler - 1; i >= 0; i--) {
if (getStickView(i, parent) != null) {
type = STICK_TYPE_VIEW;
break;
}
if (!TextUtils.isEmpty(getStickText(i, parent))) {
type = STICK_TYPE_TEXT;
break;
}
}
return type;
}
//获取某位置的上一个悬浮分隔视图
private View getLastStickView(int positionInRecycler, @NonNull RecyclerView parent) {
View lastPinnedView = null;
for (int i = positionInRecycler - 1; i >= 0; i--) {
lastPinnedView = getStickView(i, parent);
if (lastPinnedView != null) {
break;
}
}
return lastPinnedView;
}
//悬浮分隔视图
private View getStickView(int positionInRecycler, @NonNull RecyclerView parent) {
View stickView = null;
if (mStickView.get(positionInRecycler) != null) {
stickView = mStickView.get(positionInRecycler).get();
}
if (stickView == null) {
stickView = onCreateStickView(positionInRecycler, parent);
if (stickView != null) {
stickView.measure(
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
stickView.getMeasuredHeight());
stickView.setLayoutParams(layoutParams);
stickView.setDrawingCacheEnabled(true);
//指定高度、宽度的groupView
stickView.layout(0, 0, parent.getRight(), stickView.getMeasuredHeight());
stickView.buildDrawingCache();
mStickView.get(positionInRecycler, new WeakReference<>(stickView));
}
}
return stickView;
}
/**
* 悬浮分隔视图
* 子类可覆盖
*
* @param positionInRecycler RecyclerView中位置
* @param parent RecyclerView
* @return View
*/
protected View onCreateStickView(int positionInRecycler, @NonNull RecyclerView parent) {
return null;
}
}
使用（使用的RecyclerView有下拉刷新，相当于mOffsetStart = 1，故 (positionInRecycler - 1) ）：
mRecyclerView.addItemDecoration(object : StickDecoration() {
override fun onCreateStickView(positionInRecycler: Int, parent: RecyclerView): View? {
val stickSize = 30
if ((positionInRecycler - 1) % stickSize == 0) {
val mStickView = LayoutInflater.from(parent.context).inflate(R.layout.test_recycler_stick, parent, false)
var str = "${(positionInRecycler - 1)}"
if (positionInRecycler > stickSize) {
val size = (positionInRecycler - 1) / stickSize
for (i in 1 until size % 5) {
str += " \n*** $i"
}
}
mStickView?.findViewById<TextView>(R.id.test_item_text)?.text = str
return mStickView
}
return super.onCreateStickView(positionInRecycler, parent)
}
override fun onCreateStickText(positionInRecycler: Int, parent: RecyclerView): String? {
val stickSize = 20
if ((positionInRecycler - 1) % stickSize == 0) {
return "$positionInRecycler"
}
return super.onCreateStickText(positionInRecycler, parent)
}
})
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