（1）onCreateViewHolder创建ViewHolder.
（2）onBindViewHolder绑定每一项数据.
（3）getItemCount返回列表长度.
（4）RecyclerView强制使用ViewHolder.
public class MyViewHolder extends RecyclerView.ViewHolder {
private TextView mTvLabel; // 标签
private TextView mTvDateTime; // 日期
public MyViewHolder(View itemView) {
super(itemView);
mTvLabel = (TextView) itemView.findViewById(R.id.item_text);
mTvDateTime = (TextView) itemView.findViewById(R.id.item_date);
}
public TextView getTvLabel() {
return mTvLabel;
}
public TextView getTvDateTime() {
return mTvDateTime;
}
}
在onCreateViewHolder方法, 创建类; 在onBindViewHolder方法, 绑定数据.
DataModel
public class DataModel {
private String mLabel;
private Date mDateTime;
public String getLabel() {
return mLabel;
}
public void setLabel(String label) {
mLabel = label;
}
public Date getDateTime() {
return mDateTime;
}
public void setDateTime(Date dateTime) {
mDateTime = dateTime;
}
}
6. ItemDecoration
项的装饰, 比如ListView中的分割线, 在本例中, 左右两条粉线.
private void initItemDecoration(RecyclerView recyclerView) {
recyclerView.addItemDecoration(new MyItemDecoration(this));
}
ItemDecoration, 注意parent和child的使用方式.
public class MyItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
public MyItemDecoration(Context context) {
final TypedArray array = context.obtainStyledAttributes(ATTRS);
mDivider = array.getDrawable(0);
array.recycle();
}
@Override
public void onDraw(Canvas c, RecyclerView parent, State state) {
drawHorizontal(c, parent);
drawVertical(c, parent);
}
// 水平线
public void drawHorizontal(Canvas c, RecyclerView parent) {
final int childCount = parent.getChildCount();
// 在每一个子控件的底部画线
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
final int left = child.getLeft() + child.getPaddingLeft();
final int right = child.getWidth() + child.getLeft() - child.getPaddingRight();
final int top = child.getBottom() - mDivider.getIntrinsicHeight() - child.getPaddingBottom();
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
// 竖直线
public void drawVertical(Canvas c, RecyclerView parent) {
final int childCount = parent.getChildCount();
// 在每一个子控件的右侧画线
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
int right = child.getRight() - child.getPaddingRight();
int left = right - mDivider.getIntrinsicWidth();
final int top = child.getTop() + child.getPaddingTop();
final int bottom = child.getTop() + child.getHeight() - child.getPaddingBottom();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
// Item之间的留白
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, State state) {
outRect.set(0, 0, mDivider.getIntrinsicWidth(), mDivider.getIntrinsicHeight());
}
}
