tabLayout中的设置图标会抛出nullpointer异常

我正在创建一个像instagram这样的简单项目，它在主要活动中有3个选项卡 . 我想在tablayout选项卡中添加带有文本的图标，但它会抛出异常 .

My MainActivity

public class MainActivity extends AppCompatActivity {
TabLayout tabLayout;
ViewPager viewPager;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    viewPager = (ViewPager) findViewById(R.id.viewPager);
    tabLayout = (TabLayout) findViewById(R.id.tabLayout);
    tabLayout.setupWithViewPager(viewPager);

    TabLayout.Tab tab = tabLayout.getTabAt(0);

    tab.setIcon(new IconicsDrawable(this).icon(FontAwesome.Icon.faw_home));


    viewPager.setAdapter(new CustomAdapter(getSupportFragmentManager(), getApplicationContext()));


}

private class CustomAdapter extends FragmentPagerAdapter {
    private String items[] = {"Home", "Upload", "Profile"};

    public CustomAdapter(FragmentManager supportFragmentManager, Context applicationContext) {
        super(supportFragmentManager);
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new fragment1();
            case 1:
                return new fragment2();
            case 2:
                return new fragment3();
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return items.length;
    }


    @Override
    public CharSequence getPageTitle(int position) {
        return items[position];
    }
}
  }

此代码抛出nullpointer异常我该怎么办？

Exception Text

09-29 14：33：53.004 29528-29528 / com.example.eyepatch.shutter E / AndroidRuntime：FATAL EXCEPTION：main进程：com.example.eyepatch.shutter，PID：29528 java.lang.RuntimeException：无法启动activity ComponentInfo {com.example.eyepatch.shutter / com.example.eyepatch.shutter.MainActivity}：java.lang.NullPointerException：尝试调用虚方法'android.support.design.widget.TabLayout $ Tab android.support.design .widget.TabLayout $ Tab.setIcon（android.graphics.drawable.Drawable）'在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java）的android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2434）上的空对象引用上：2494）在Android.app.Handler.dispatchMessage（Handler.java:102）的android.app.ActivityThread.access $ 900（ActivityThread.java:157）android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1356） ）在android.app.Looper.loop（Looper.java:148）的android.app.ActivityThread.main（ActivityThread.java:5530）java.lang.reflect.Method.i在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:733）的com.android.internal.os.ZygoteInit.main（ZygoteInit.java:623）中的nvoke（Native Method）引起：java . lang.NullPointerException：尝试在null对象引用上调用虚方法'android.support.design.widget.TabLayout $ Tab android.support.design.widget.TabLayout $ Tab.setIcon（android.graphics.drawable.Drawable）' android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1108）在android.app.Activity.performCreate（Activity.java:6272）上的com.example.eyepatch.shutter.MainActivity.onCreate（MainActivity.java:33） Android.app.ActivityThread上的android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2494）android.app.ActivityThread.access $ 900（ActivityThread.java:157）的.app.ActivityThread.performLaunchActivity（ActivityThread.java:2387） $ H.handleMessage（ActivityThread.java:1356）在android.os.Handler.dispatchMessage（Handler.java:102）的android.os.Looper.loop（Looper . java：148）at android.app.ActivityThread.main（ActivityThread.java:5530）at java.lang.reflect.Method.invoke（Native Method）at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit . java：733）at com.android.internal.os.ZygoteInit.main（ZygoteInit.java:623）