Bundle是Android特有的一种类,主要用于传递数据;保存的数据,Bundle是一个信息的载体,内部维护了一个Map
在activity间传递信息:
Intent.putExtra(bundle);
Activity读取数据:
Bundle bundle = this.getIntent().getExtras(); //读取intent的数据携带的bundle对象 String str1 = bundle.getString("sff"); //通过key得到value int int1 = bundle.getInt("iff"); //通过key得到value2、面向对象的接口思想
IFragmentCallback.java:
public interface IFragmentCallback { void sendMsgToActivity(String string); String getMsgFromActivity(String string); }
Fragment.java:向Activity发送数据
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment if(rootView == null) { rootView = inflater.inflate(R.layout.fragment_blank1, container, false); } Button btn = rootView.findViewById(R.id.btn_fragment1); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { //向Activity发送数据 fragmentCallback.sendMsgToActivity("hello,I'm from fragment"); } }); return rootView; }
Activity.java:接收Fragment发送的数据并显示
public void onClick(View view) { switch (view.getId()){ case R.id.btn1: Bundle bundle = new Bundle();//保存数据的类 bundle.putString("message","我是一个工程师"); BlankFragment1 bf1 = new BlankFragment1(); bf1.setArguments(bundle); bf1.sendFragmentCallback(new IFragmentCallback() { @Override public void sendMsgToActivity(String string) { Toast.makeText(MainActivity.this,string,Toast.LENGTH_LONG).show(); } break; } }
Fragment.java:接收Activity的数据
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment if(rootView == null) { rootView = inflater.inflate(R.layout.fragment_blank1, container, false); } Button btn = rootView.findViewById(R.id.btn_fragment1); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { //接收Activity数据 String msg = fragmentCallback.getMsgFromActivity("null"); Toast.makeText(BlankFragment1.this.getContext(),msg,Toast.LENGTH_LONG).show(); } }); return rootView; }
Activity.java:接收Fragment请求的数据传递
public void onClick(View view) { switch (view.getId()){ case R.id.btn1: Bundle bundle = new Bundle();//保存数据的类 bundle.putString("message","我是一个工程师"); BlankFragment1 bf1 = new BlankFragment1(); bf1.setArguments(bundle); bf1.sendFragmentCallback(new IFragmentCallback() { @Override public void sendMsgToActivity(String string) { Toast.makeText(MainActivity.this,string,Toast.LENGTH_LONG).show(); } @Override public String getMsgFromActivity(String string) { return "hello,I'm from activity"; //return string; } }); break; } }
缺点:必须保证双方都会接收到对方的请求,否则无法成功传递数据。
3、其他方案:利用观察者模式 or 发布订阅模式,利用模式架构来管理(进阶,待补充。。。。)
A、eventBus
B、LiveData...