在不使用viewpager的情况下使用选项卡按钮更改片断

// 主Activity
public class MainActivity extends AppCompatActivity {
    private FragmentManager fragmentManager;
    private Button tab1Button, tab2Button;
    private Fragment fragment1, fragment2;

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

        fragmentManager = getSupportFragmentManager();

        tab1Button = findViewById(R.id.tab1_button);
        tab2Button = findViewById(R.id.tab2_button);

        fragment1 = new Fragment1();
        fragment2 = new Fragment2();

        // 默认显示第一个Fragment
        fragmentManager.beginTransaction().replace(R.id.fragment_container, fragment1).commit();

        tab1Button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                fragmentManager.beginTransaction().replace(R.id.fragment_container, fragment1).commit();
            }
        });

        tab2Button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                fragmentManager.beginTransaction().replace(R.id.fragment_container, fragment2).commit();
            }
        });
    }
}