动态添加fragment

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
        int width = wm.getDefaultDisplay().getWidth();
        int height = wm.getDefaultDisplay().getHeight();
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();
        if (width < height) {
            ft.replace(android.R.id.content, new Fragment1());
        } else {
            ft.replace(android.R.id.content, new Frgment2());
        }
        ft.commit();
    }
}

        FragmentManager fm = getSupportFragmentManager();