Android中Activity和Fragment之间的通信

Android中Activity和Fragment之间的通信

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• 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() {            @Override            public 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 @Override    public 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@Override        public 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ID            textView.setOnClickListener(new View.OnClickListener() {                @Override                public 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@Override    public void onListItemClick(ListView l, View v, int position, long id) {        // TODO Auto-generated method stub        super.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@Override    public void onCreate(Bundle savedInstanceState) {        // TODO Auto-generated method stub        super.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Fragment            ContentFragment 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() {            @Override            public void getData(List<NewsBean> list) {                data.addAll(list);                adapter.notifyDataSetChanged();            }        });        myTask.execute(values);