Android中Activity和Fragment之间的通信

Fragment启动Activity传数据到Fragment
举例：城市选择列表。一个Fragment启动Activity，Activity再把城市选择数据回传到Fragment中。

Fragment中方法iv_city.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// Toast.makeText(getActivity(), "点击了", Toast.LENGTH_SHORT).show();Intent intent=new Intent(getActivity(), CityActivity.class);startActivityForResult(intent,0);}});重写onActivityResult方法@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);Log.d("tag", "返回结果"+resultCode);// 取出intent中的值// 一般，加个null判断if (data != null) {String stringExtra = data.getStringExtra("city");cityid= data.getStringExtra("cityId");Log.d("tag", "城市ID"+cityid);getData(10);// 把取出的值设置到et_name中if (resultCode==1) {tv_city.setText(stringExtra);}}}

CityActivity@Overridepublic void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {final TextView textView = (TextView) holder.itemView;textView.setText(getItem(position).getCityName());//得到城市名
//            final String cityId = getItem(position).getCityId();//得到城市IDtextView.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {Toast.makeText(CityActivity.this, "选择城市："+textView.getText(), Toast.LENGTH_SHORT).show();// Intent intent =new Intent();Intent intent = getIntent();intent.putExtra("city",textView.getText().toString());//for (int i = 0; i < cities.size(); i++) {if (textView.getText().toString().equals(cities.get(i).getCityName())){cityId = cities.get(i).getCityId();}}intent.putExtra("cityId",cityId);setResult(1,intent);finish();}});}

Fragment传数据到Fragment
举例：左边是电影列表的Fragment,右边是一个电影的具体内容的Fragment。点击左边的Fragment传数据给右边的Fragment显示。可以通过Fragment的fragment.setArguments(bundle)传。

MovieListFragment@Overridepublic void onListItemClick(ListView l, View v, int position, long id) {// TODO Auto-generated method stubsuper.onListItemClick(l, v, position, id);//当Item被点击，调用Toast.makeText(getActivity(), names[position]+":"+files[position], Toast.LENGTH_LONG).show();//点击时，获取Files数组对应的内容//把获取的内容传给Fragment  //加载对应的Fragment//5步骤MovieContentFragment fragment=new MovieContentFragment();//把传参传入到Fragment    Bundle bundle=new Bundle();bundle.putString("fileName", files[position]);fragment.setArguments(bundle);FragmentManager fm = getFragmentManager();FragmentTransaction transaction = fm.beginTransaction();transaction.replace(R.id.flayout, fragment);transaction.commit();}

MovieContentFragment@Overridepublic void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);// 取出参数Bundle bundle = getArguments();String name = bundle.getString("fileName");// 根据文件名，解析对应内容

Activity传数据到Fragment
举例：新闻头部标签加载对应的Fragment. Activity通过传不同的url地址构建不同的Fragment。

Activity/*** 初始化List<Fragment>*/private void initFragment() {fragments = new ArrayList<>();//根据标题的个数，循环创建Fragment,int len = titles.length;for (int i = 0; i < len; i++) {//创建一个新的FragmentContentFragment cf = new ContentFragment();//传入参数，以便构造不同的数据Bundle bundle = new Bundle();bundle.putString("key", urls[i]);cf.setArguments(bundle);//添加到Fragment集合中fragments.add(cf);}}

Fragment//获取传入的参数，根据参数构造不同的数据Bundle bundle = getArguments();String values = bundle.getString("key");//异步任务MyTask myTask=new MyTask(new MyTask.CallBack() {@Overridepublic void getData(List<NewsBean> list) {data.addAll(list);adapter.notifyDataSetChanged();}});myTask.execute(values);