此自定义ItemDecoration采用Builder模式，可根据需求设置上下左右分割线的是否显示、颜色、和分割线的高度。
/**
* @ClassName: LinearItemDecoration
* @Description: 线性Recyclerview分割线
* @Author: CHN_Liao
* @CreateDate: 2020-11-02 16:59
*/
public class LinearItemDecoration extends RecyclerView.ItemDecoration {
private Context mContext;
//顶部是否增加分割线
private boolean isDividerTop = false;
//左边是否增加分割线
private boolean isDividerLeft = false;
//右边是否增加分割线
private boolean isDividerRight = false;
//底部是否增加分割线,默认为true
private boolean isDividerBottom = true;
//顶部分割线颜色;
private int dividerTopColor;
//左边分割线颜色;
private int dividerLeftColor;
//右边分割线颜色;
private int dividerRightColor;
//底部分割线颜色;
private int dividerBottomColor;
//分割线画笔
private Paint dividerPaint;
//分割线高度
private int dividerHeight = 4;
public LinearItemDecoration(Context context) {
mContext = context;
dividerPaint = new Paint();
//默认分割线颜色
dividerTopColor = dividerLeftColor = dividerRightColor = dividerBottomColor = Color.GRAY;
}
@Override
public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
outRect.bottom = isDividerBottom ? dividerHeight : 0;
outRect.left = isDividerLeft ? dividerHeight : 0;
outRect.right = isDividerRight ? dividerHeight : 0;
outRect.top = isDividerTop ? dividerHeight : 0;
}
@Override
public void onDraw(@NonNull Canvas canvas, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.onDraw(canvas, parent, state);
int childCount = parent.getChildCount();
//绘制头部分割线颜色
drawTop(canvas, parent, childCount);
//绘制左边分割线颜色
drawLeft(canvas, parent, childCount);
//绘制右边分割线颜色
drawRight(canvas, parent, childCount);
//绘制底部分割线颜色
drawBottom(canvas, parent, childCount);
}
private void drawTop(@NonNull Canvas canvas, @NonNull RecyclerView parent, int childCount) {
if (!isDividerTop) return;
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
for (int i = 0; i < childCount; i++) {
View view = parent.getChildAt(i);
float top = view.getTop() - dividerHeight;
float bottom = view.getTop();
dividerPaint.setColor(dividerTopColor);
canvas.drawRect(left, top, right, bottom, dividerPaint);
}
}
private void drawLeft(@NonNull Canvas canvas, @NonNull RecyclerView parent, int childCount) {
if (!isDividerLeft) return;
int left = parent.getPaddingLeft();
int right = parent.getPaddingLeft() + dividerHeight;
dividerPaint.setColor(dividerLeftColor);
for (int i = 0; i < childCount; i++) {
View view = parent.getChildAt(i);
float top = view.getTop();
float bottom = view.getBottom();
canvas.drawRect(left, top, right, bottom, dividerPaint);
}
}
private void drawRight(@NonNull Canvas canvas, @NonNull RecyclerView parent, int childCount) {
if (!isDividerRight) return;
int left = parent.getRight() - parent.getPaddingRight() - dividerHeight;
int right = parent.getRight() - parent.getPaddingRight();
dividerPaint.setColor(dividerRightColor);
for (int i = 0; i < childCount; i++) {
View view = parent.getChildAt(i);
float top = view.getTop();
float bottom = view.getBottom();
canvas.drawRect(left, top, right, bottom, dividerPaint);
}
}
private void drawBottom(@NonNull Canvas canvas, @NonNull RecyclerView parent, int childCount) {
if (!isDividerBottom) return;
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
dividerPaint.setColor(dividerBottomColor);
for (int i = 0; i < childCount - 1; i++) {
View view = parent.getChildAt(i);
float top = view.getBottom();
float bottom = view.getBottom() + dividerHeight;
canvas.drawRect(left, top, right, bottom, dividerPaint);
}
}
public static class Builder {
private Context context;
private LinearItemDecoration itemDecoration;
public Builder(Context context) {
this.context = context;
itemDecoration = new LinearItemDecoration(context);
}
//设置是否显示各个分割线，默认显示底部分割线
public Builder showDividers(boolean top, boolean left, boolean right, boolean bottom) {
itemDecoration.isDividerTop = top;
itemDecoration.isDividerLeft = left;
itemDecoration.isDividerRight = right;
itemDecoration.isDividerBottom = bottom;
return this;
}
//分割线高度(dp)
public Builder dividerHeight(int dividerHeight) {
itemDecoration.dividerHeight = dp2px(dividerHeight);
return this;
}
private int dp2px(float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
//统一分割线颜色
public Builder dividerColor(@ColorRes int color) {
int c = context.getResources().getColor(color);
itemDecoration.dividerTopColor = c;
itemDecoration.dividerLeftColor = c;
itemDecoration.dividerRightColor = c;
itemDecoration.dividerBottomColor = c;
return this;
}
//设置各个分割线颜色
public Builder dividerColors(@ColorRes int topColor,@ColorRes int leftColor,@ColorRes int rightColor,@ColorRes int bottomColor) {
itemDecoration.dividerTopColor = context.getResources().getColor(topColor);
itemDecoration.dividerLeftColor = context.getResources().getColor(leftColor);
itemDecoration.dividerRightColor = context.getResources().getColor(rightColor);
itemDecoration.dividerBottomColor = context.getResources().getColor(bottomColor);
return this;
}
public LinearItemDecoration build() {
return itemDecoration;
}
}
}
快速实现及效果如下：
LinearItemDecoration itemDecoration = new LinearItemDecoration.Builder(this).build();
recyclerView.addItemDecoration(itemDecoration);
效果0.png
其他配置代码实现及效果如下：
LinearItemDecoration itemDecoration = new LinearItemDecoration.Builder(this)
// .dividerColor(R.color.green)//统一分割线颜色
.dividerColors(R.color.green,R.color.blue,R.color.colorAccent,R.color.colorPrimaryDark)//设置各个分割线的颜色
.showDividers(true,true,true,true)//设置各个分割线是否显示,默认只显示底部分割线
.dividerHeight(4)//设置分割线高度(单位:dp)
.build();
recyclerView.addItemDecoration(itemDecoration);
效果1.png
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