一、源代码
package study.yang.definedivideritemview;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
public class DefineDividerItem extends RecyclerView.ItemDecoration {
//水平
public static final int HORIZONTAL = 0;
//垂直
public static final int VERTICAL = 1;
private static final String TAG = "DefineDividerItem";
//分割线Drawable
private Drawable mDivider;
//分割线位置
private int mOrientation = 1;
private final Rect mBounds = new Rect();
/**
* 设置分割线的方向
*
* @param orientation
*/
public void setOrientation(int orientation) {
if (orientation != 0 && orientation != 1) {
throw new IllegalArgumentException("Invalid orientation. It should be either HORIZONTAL or VERTICAL");
} else {
this.mOrientation = orientation;
}
}
/**
* 设置分割线的样式
*
* @param drawable
*/
public void setDrawable(@NonNull Drawable drawable) {
if (drawable == null) {
throw new IllegalArgumentException("Drawable cannot be null.");
} else {
this.mDivider = drawable;
}
}
@Override
public void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
if (parent.getLayoutManager() != null && this.mDivider != null) {
if (this.mOrientation == 1) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
}
/**
* 绘制垂直线
*
* @param
* @param parent
*/
private void drawVertical(Canvas canvas, RecyclerView parent) {
canvas.save();
int left;
int right;
if (parent.getClipToPadding()) {
left = parent.getPaddingLeft();
right = parent.getWidth() - parent.getPaddingRight();
canvas.clipRect(left, parent.getPaddingTop(), right, parent.getHeight() - parent.getPaddingBottom());
} else {
left = 0;
right = parent.getWidth();
}
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; ++i) {
View child = parent.getChildAt(i);
parent.getDecoratedBoundsWithMargins(child, this.mBounds);
//子View的测量高度
int childMeasuredHeight = child.getMeasuredHeight();
int bottom = this.mBounds.bottom + - childMeasuredHeight;
int top = bottom - this.mDivider.getIntrinsicHeight() - childMeasuredHeight;//-child.getMeasuredHeight()
//将mBounds的位置信息再传递给mDivider的Bounds
this.mDivider.setBounds(left, top, right, bottom);
//绘制mDivider
this.mDivider.draw(canvas);
}
canvas.restore();
}
/**
* 绘制水平线
*
* @param canvas
* @param parent
*/
private void drawHorizontal(Canvas canvas, RecyclerView parent) {
canvas.save();
int top;
int bottom;
if (parent.getClipToPadding()) {
top = parent.getPaddingTop();
bottom = parent.getHeight() - parent.getPaddingBottom();
canvas.clipRect(parent.getLeft(), top, parent.getRight() - parent.getPaddingRight(), bottom);
} else {
top = 0;
bottom = parent.getHeight();
}
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; ++i) {
View child = parent.getChildAt(i);
parent.getDecoratedBoundsWithMargins(child, this.mBounds);
//子View的测量宽度
int measuredWidth = child.getMeasuredWidth();
int right = this.mBounds.right - measuredWidth;
int left = right - this.mDivider.getIntrinsicWidth() - measuredWidth;//-child.getMeasuredHeight()
//将mBounds的位置信息再传递给mDivider的Bounds
this.mDivider.setBounds(left, top, right, bottom);
//绘制mDivider
this.mDivider.draw(canvas);
}
canvas.restore();
}
@Override
public void onDrawOver(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.onDrawOver(c, parent, state);
Log.e(TAG, "onDrawOver");
}
@Override
public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
int position = layoutManager.getPosition(view);
int childCount = layoutManager.getChildCount();
RecyclerView.Adapter parentAdapter = parent.getAdapter();
int totalChildCount = parentAdapter.getItemCount() - 1;
//获取mDivider的内在高度
if (mOrientation == VERTICAL) {
int intrinsicHeight = mDivider.getIntrinsicHeight();
getItemVerticalOffsets(outRect, intrinsicHeight, position, totalChildCount);
} else {
int intrinsicWidth = mDivider.getIntrinsicWidth();
getItemHorizontalOffsets(outRect, intrinsicWidth, position, totalChildCount);
}
}
/**
* 获取水平的条目偏移
*
* @param outRect
* @param offsets
* @param position
* @param totalChildCount
*/
private void getItemHorizontalOffsets(Rect outRect, int offsets, int position, int totalChildCount) {
if (position == totalChildCount) {
//保证最后一个条目距离屏幕底部也有间隔
outRect.set(offsets, 0, offsets, 0);
} else {
outRect.set(offsets, 0, 0, 0);
}
}
/**
* 获取垂直的条目偏移
*
* @param outRect
* @param offsets 偏移度
*/
private void getItemVerticalOffsets(Rect outRect, int offsets, int position, int totalChildCount) {
if (position == totalChildCount) {
//保证最后一个条目距离屏幕底部也有间隔
outRect.set(0, offsets, 0, offsets);
} else {
outRect.set(0, offsets, 0, 0);
}
}
}
源代码
