Android中Fragment的加载方式与数据通信详解

<!--指定在layout中实例化的Fragment类，需要为“包名.类名”的完整形式-->
android:name
<!--唯一标识，id和tag可任选其一，不可两者都没有-->
android:id
android:tag

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="match_parent"
 android:layout_height="match_parent">
 <TextView
 android:id="@+id/fragment_text"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content" />
</LinearLayout>

public class MyFragment extends Fragment {
 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 //将layout布局转换成View对象
 View view = inflater.inflate(R.layout.myfragment, container, false);
 //必须通过view对象对其子组件进行访问
 TextView textView = (TextView) view.findViewById(R.id.fragment_text);
 textView.setText("这里是fragment");
 //返回Fragment显示UI
 return view;
 }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent" tools:context="com.studying.StaticFragmentActivity">
 <fragment
 android:tag="fragment"
android:name="com.joahyau.studying.MyFragment"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"/>
</LinearLayout>

public class StaticFragmentActivity extends Activity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_static_fragment);
 //可直接通过findViewById访问
 findViewById(R.id.fragment_text).setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  Toast.makeText(StaticFragmentActivity.this, "点击了文本", Toast.LENGTH_SHORT).show();
  }
 });
 }
}

FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
tools:context="io.github.joahyau.studying.DynamicFragmentActivity">
 <Button
 android:id="@+id/load"
 android:text="加载"
 android:layout_width="match_parent"
 android:layout_height="80dp" />
 <LinearLayout
 android:id="@+id/container"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:orientation="horizontal" />
</LinearLayout>

public class DynamicFragmentActivity extends Activity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_dynamic_fragment);
 findViewById(R.id.load).setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  //获取事务管理器
  FragmentManager fragmentManager = getFragmentManager();
  FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  //创建fragment，并将其动态加载到id位container的布局中
  MyFragment myFragment = new MyFragment();
  fragmentTransaction.add(R.id.container, myFragment);
  //提交事务
  fragmentTransaction.commit();
  }
 });
 }
}

public class MainActivity extends Activity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 findViewById(R.id.send).setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  //创建Fragment对象
  MyFragment myFragment = new MyFragment();
  //创建Bundle对象并传入数据
  Bundle bundle = new Bundle();
  bundle.putString("info", "这里是向Fragment传递的数据");
  myFragment.setArguments(bundle);
  //加载Fragment
  FragmentManager fragmentManager = getFragmentManager();
  FragmentTransaction beginTransaction = fragmentManager.beginTransaction();
  beginTransaction.add(R.id.layout, myFragment, "myfragment");
  beginTransaction.commit();
  }
 });
 }
}

public class MyFragment extends Fragment {
 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 View view = inflater.inflate(R.layout.my_fragment, container, false);
 TextView tv = (TextView) view.findViewById(R.id.text);
 //获取数据
 String text = getArguments().get("info") + "";
 tv.setText(text);
 return view;
 }
}

public class MyFragment extends Fragment {
 private Button btn;
 private String received;//作为容器的对象
 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 View view = inflater.inflate(R.layout.my_fragment, container, false);
 TextView tv = (TextView) view.findViewById(R.id.text);
 tv.setText("这里是Fragment");
 btn = (Button) view.findViewById(R.id.send);
 btn.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  Toast.makeText(getActivity(), "成功接收\"" + getReceived() + "\"", Toast.LENGTH_SHORT).show();
  }
 });
 return view;
 }
 public String getReceived() {
 return received;
 }
 public void setReceived(String received) {
 this.received = received;
 }
}

public class MainActivity extends Activity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 FragmentManager fragmentManager = getFragmentManager();
 MyFragment myFragment = (MyFragment) fragmentManager.findFragmentById(R.id.my_fragment);
 myFragment.setReceived("this is a test.");
 }
}

public class MyFragment extends Fragment {
 private SendData sendData;
 @Override
 public void onAttach(Activity activity) {
 super.onAttach(activity);
 //获取实现的接口对象
 sendData = (SendData) activity;
 }
 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 View view = inflater.inflate(R.layout.my_fragment, container, false);
 TextView tv = (TextView) view.findViewById(R.id.text);
 tv.setText("这里是Fragment");
 //通过接口对象传递数据
 sendData.sendMsg("this is a test.");
 return view;
 }
 //定义一个回调接口
 public interface SendData{
 void sendMsg(String str);
 }
}

public class MainActivity extends Activity implements MyFragment.SendData{
 private Button btn;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 btn = (Button) findViewById(R.id.send);
 btn.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  MyFragment myFragment = new MyFragment();
  FragmentManager fragmentManager = getFragmentManager();
  FragmentTransaction beginTransaction = fragmentManager.beginTransaction();
  beginTransaction.add(R.id.layout, myFragment);
  beginTransaction.commit();
  }
 });
 }
 //实现SendData接口，接收数据
 @Override
 public void sendMsg(String str) {
 Toast.makeText(this, "成功接收\"" + str + "\"", Toast.LENGTH_SHORT).show();
 }
}