1.先来张效果图

2.自定义一个角标工具类BottomBarView 。
**
* Created by Administrator on 2016/12/27.
* 角标工具类
*/
public class BottomBarView extends RelativeLayout {
private Context context;
private TextView bar_num;
private int count = 0;
public BottomBarView(Context context) {
this(context, null);
}
public BottomBarView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public BottomBarView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
RelativeLayout rl = (RelativeLayout) LayoutInflater.from(context).inflate(R.layout.bottom_bar_view, this, true);
bar_num = (TextView) rl.findViewById(R.id.bar_num);
bar_num.setVisibility(GONE);
}
public void add() {
bar_num.setVisibility(VISIBLE);
count++;
if (count < 100) {
bar_num.setText(count + "");
} else {
bar_num.setText("99+");
}
}
public void add(int n) throws Exception {
if(n<0){
throw new Exception(BottomBarView.class.getSimpleName()+" add(int n).The param must be a positive num");
}
bar_num.setVisibility(VISIBLE);
count += n;
if (count < 100) {
bar_num.setText(count + "");
} else {
bar_num.setText("99+");
}
}
public void delete() {
if (count == 0) {
bar_num.setVisibility(GONE);
} else {
count--;
if (count == 0) {
bar_num.setVisibility(GONE);
} else if (count > 0 && count < 100) {
bar_num.setVisibility(VISIBLE);
bar_num.setText(count + "");
} else {
bar_num.setVisibility(VISIBLE);
bar_num.setText("99+");
}
}
}
public void deleteAll() {
count = 0;
bar_num.setVisibility(GONE);
}
}