import android.os.Bundle;import android.annotation.SuppressLint;import android.support.v4.app.FragmentActivity;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.view.WindowManager;@SuppressLint("CommitTransaction")public class MainActivity extends FragmentActivity {    @SuppressWarnings("deprecation")    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // [1]获取手机的宽和高 windommanager        WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);        int width = wm.getDefaultDisplay().getWidth();        int height = wm.getDefaultDisplay().getHeight();        // [2]判断横竖屏        // [3.1]如果使用v4包中的fragment 获取fragment的管理者 是通过getsupportFragmentManager();        FragmentManager supportFragmentManager = getSupportFragmentManager();                        // [3.2]开启一个事务        FragmentTransaction transaction = supportFragmentManager.beginTransaction();        if (height > width) {            // 说明是竖屏 androind 代表系统定义好的 android.R.id.content理解成是当前手机的窗体            transaction.replace(android.R.id.content, new Fragment1());        } else {            // 横屏            transaction.replace(android.R.id.content, new Fragment2());        }        //[4]一定要记得 提交commit         transaction.commit();                    }}