Android中TabLayout添加小红点的示例代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  tools:context="com.bxkj.dylan.tablayoutreddot.MainActivity">
  <android.support.design.widget.TabLayout
    android:id="@+id/tabLayout"
    app:tabBackground="@android:color/white"
    app:tabTextColor="@color/colorBlack"
    app:tabSelectedTextColor="@color/colorAccent"
    app:tabMode="scrollable"
    android:layout_width="match_parent"
    android:layout_height="40dp" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="40dp"
  android:layout_gravity="center"
  android:orientation="horizontal">
  <TextView
    android:id="@+id/tv_tab_title"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:gravity="center"
    android:textColor="@color/colorBlack"
    android:textSize="15sp" />
  <TextView
    android:id="@+id/iv_tab_red"
    android:layout_gravity="right"
    android:layout_width="18dp"
    android:text="5"
    android:gravity="center"
    android:textColor="@android:color/white"
    android:layout_height="18dp"
    android:background="@drawable/red_dot" />
</LinearLayout>

import android.content.res.Resources;
import android.support.design.widget.TabLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
/**
 * @author dylan
 */
public class MainActivity extends AppCompatActivity {
  private TabLayout tabLayout;
  private TextView tv_tab_title;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tabLayout = findViewById(R.id.tabLayout);
    initData();
  }

  private void initData() {
    TabLayout.Tab tab = tabLayout.newTab().setText("全部");
    tabLayout.addTab(tab);
    //待付款栏目-加载自定义显示小红点的布局
    tab = tabLayout.newTab();
    tab.setCustomView(R.layout.tab_wait_for_pay);
    tv_tab_title = tab.getCustomView().findViewById(R.id.tv_tab_title);
    tv_tab_title.setText("待付款");
    tabLayout.addTab(tab);
    tab = tabLayout.newTab().setText("待发货");
    tabLayout.addTab(tab);
    tab = tabLayout.newTab().setText("待收货");
    tabLayout.addTab(tab);
    tab = tabLayout.newTab().setText("已完成");
    tabLayout.addTab(tab);
    tab = tabLayout.newTab().setText("已取消");
    tabLayout.addTab(tab);
    //添加tabLayout选中监听
    tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
      @Override
      public void onTabSelected(TabLayout.Tab tab) {
        //设置选中时的文字颜色
        if (tab.getCustomView() != null) {
          tv_tab_title.setTextColor(getResources().getColor(R.color.colorAccent));
        }
      }

      @Override
      public void onTabUnselected(TabLayout.Tab tab) {
        //设置未选中时的文字颜色
        if (tab.getCustomView() != null) {
          tv_tab_title.setTextColor(getResources().getColor(R.color.colorBlack));
        }
      }

      @Override
      public void onTabReselected(TabLayout.Tab tab) {
      }
    });
  }
}