安卓Fragment的切换

// 初始化默认显示的界面	if (purchaserHomeFragment == null) {	purchaserHomeFragment = new PurchaserHomeFragment();	addFragment(purchaserHomeFragment);	showFragment(purchaserHomeFragment);	} else {	showFragment(purchaserHomeFragment);	} // 购物车界面	if (purchaserCarFragment == null) {	purchaserCarFragment = new PurchaserCarFragment();	// 判断当前界面是否隐藏，如果隐藏就进行添加显示，false表示显示，true表示当前界面隐藏	if (!purchaserCarFragment.isHidden()) {	addFragment(purchaserCarFragment);	showFragment(purchaserCarFragment);	}	} else {	if (purchaserCarFragment.isHidden()) {	showFragment(purchaserCarFragment);	}	}	/** 添加fragment **/	public void addFragment(Fragment fragment) {	FragmentTransaction ft = this.getSupportFragmentManager().beginTransaction();	ft.add(R.id.fl_content, fragment);	ft.commit();	}	/** 显示fragment **/	public void showFragment(Fragment fragment) {	FragmentTransaction ft = this.getSupportFragmentManager().beginTransaction();	// 判断页面是否已经创建，如果已经创建，那么就隐藏掉	if (purchaserHomeFragment != null) {	ft.hide(purchaserHomeFragment);	}	if (purchaserTypeFragment != null) {	ft.hide(purchaserTypeFragment);	}	if (purchaserOrderFragment != null) {	ft.hide(purchaserOrderFragment);	}	if (purchaserCarFragment != null) {	ft.hide(purchaserCarFragment);	}	ft.show(fragment);	ft.commitAllowingStateLoss();	}