Android之Fragment动态加载、Fragment与Activity传值通信

1、Fragment动态加载

Fragment动态加载：撰写代码将Fragment灵活添加到一个Activity 中。add()添加、remove()移除、替换等。

（1）处理Fragment事务

FragmentManager fragmentManager = getFragmentManager();    //获得Fragment的管理者FragmentTransaction beginTransaction = fragmentManager.beginTransaction();  //开启Fragment的事务，从而进行添加移除操作

每一个事务都是同时执行一套变化，可以在一个事务中设置你所有执行的变化，包括add（）、remove（）、replace（），然后提交给Activity（commit()）。

如果允许用户通过按下BACK键返回到前一个Fragment状态，调用commit（）之前还要加入addToBackStack（）方法。

case R.id.second://演示动态加载DongTaiMyFragment dongTaiMyFragment=new DongTaiMyFragment();            FragmentManager fragmentManager = getFragmentManager();            FragmentTransaction beginTransaction = fragmentManager.beginTransaction();            beginTransaction.add(R.id.frame, dongTaiMyFragment);    //通过事务去管理Fragment            beginTransaction.addToBackStack(null);    //处理返回键            beginTransaction.commit();  //提交break;

2、与Activity传值通信

          A. Fragment调用getActivity（）方法获取它所在的Activity；
              Activity调用FragmentManager的findFragmentById（）或者findFragmentByTag（）方法获取Fragment；
          B. Activity——》Fragment：在Activity中创建Bundle数据包，并调用Fragment的setArguments（Bundle bundle）方法；

              Fragment——》Activity：需要在Fragment中定义一个内部回调接口，让包含该Fragment的Activity实现该回调接口。这样Fragment可调用回调方法将数据传递给Activity。

Activity：

public class MainActivity extends Activity implements MyListenter{private EditText editText;private Button activitySendBtn;//private TextView textView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);editText=(EditText) findViewById(R.id.activitySendET);activitySendBtn=(Button) findViewById(R.id.btnSend);activitySendBtn.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString text = editText.getText().toString();Bundle bundle=new Bundle();bundle.putString("name", text);MainFragment fragment=new MainFragment();fragment.setArguments(bundle);/*Intent intent=new Intent(MainActivity.this, FragmentActivity.class);startActivity(intent);*///动态加载FragmentManager fragmentManager = getFragmentManager();FragmentTransaction transaction = fragmentManager.beginTransaction();transaction.add(R.id.activity, fragment,"fragment");transaction.commit();Toast.makeText(MainActivity.this,"向Fragment询问姓名：" + text, Toast.LENGTH_SHORT).show();}});//静态加载FragmentManager manager = getFragmentManager();Fragment findFragment = manager.findFragmentById(R.id.sendFragment);MainFragment frag=(MainFragment) findFragment;frag.setStr("Fragment静态传递值");}@Overridepublic void answer(String name) {// TODO Auto-generated method stubToast.makeText(MainActivity.this, "已成功接收到:"+name, Toast.LENGTH_LONG);}}

Fragment：

public class MainFragment extends Fragment {private String name="Fragment回复姓名：Jone";private TextView textView;private Button button;//内部接口public interface MyListenter{public void answer(String name);}public MyListenter myListenter;@Overridepublic void onAttach(Activity activity) {// TODO Auto-generated method stubmyListenter=(MyListenter) activity;super.onAttach(activity);}//静态加载传递private String str="";public String getStr() {return str;}public void setStr(String str) {this.str = str;}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {// TODO Auto-generated method stubView view =inflater.inflate(R.layout.fragment_main,container, false);textView=(TextView) view.findViewById(R.id.questionText);String text=getArguments().getString("name").toString();textView.setText(text);Toast.makeText(getActivity(), "成功接收到问题："+text, Toast.LENGTH_SHORT).show();//myListenter.answer(name);//button=(Button) view.findViewById(R.id.fragBtn);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString value=getStr();Toast.makeText(getActivity(), "value="+value, Toast.LENGTH_SHORT);}});return view;}}