Android开发之Fragment与Activity的数据交互通过回调机制实现

 上一篇文章简单介绍了Android的回调机制的使用，这一篇博文将重点介绍Fragment碎片与activity的数据交互，fragment在Android开发中起着至关重要的作用，通过官方Android api我们可以看到，fragment有着自己的生命周期并依赖于它绑定的activity的生命周期而存在，那样activity与fragment怎样进行数据交互呢，请看此篇博文。

MainActiivity的代码

 package com.example.f08_fragment03;

 import com.example.f08_fragment03.Fragment02.Callback;

 import android.os.Bundle;
 import android.app.Activity;
 import android.app.FragmentManager;
 import android.app.FragmentTransaction;
 import android.view.Menu;
 import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;

 public class MainActivity extends Activity {
     private FragmentManager manager;// 创建fragment管理
     private FragmentTransaction transaction;// 创建fragment的事物
     private EditText editText;
     private Button button;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         editText = (EditText) this.findViewById(R.id.editText2);
         button = (Button) this.findViewById(R.id.button1);
         manager = getFragmentManager();
         transaction = manager.beginTransaction();
         final Fragment02 fragment02 = new Fragment02();
         transaction.add(R.id.left, fragment02, "left");
         transaction.commit();
         // 不管要实现怎样的功能都必须调用以下三个方法
         // manager=getFragmentManager();
         //transaction=manager.beginTransaction();
         // transaction.commit();提交数据
         button.setOnClickListener(new View.OnClickListener() {

             @Override
             public void onClick(View arg0) {
                 // TODO Auto-generated method stub
                 //通过callback机制得到fragment的数据
                 fragment02.getString(new Callback() {

                     @Override
                     public void getString(String msg) {
                         // TODO Auto-generated method stub
                         editText.setText(msg);
                     }
                 });
             }
         });
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.main, menu);
         return true;
     }

 }

Fragment02的代码

 package com.example.f08_fragment03;

 import android.app.Activity;
 import android.app.Fragment;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.EditText;

 public class Fragment02 extends Fragment {
     private Button button;
     private EditText editText;

     @Override
     public void onAttach(Activity activity) {
         // TODO Auto-generated method stub
         super.onAttach(activity);
     }

     @Override
     public void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         super.onCreate(savedInstanceState);
     }

     // 在该方法中更新UI
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
             Bundle savedInstanceState) {
         // TODO Auto-generated method stub

         View view = inflater.inflate(R.layout.left, null);
         button = (Button) view.findViewById(R.id.button1);
         editText = (EditText) view.findViewById(R.id.editText1);
         button.setOnClickListener(new View.OnClickListener() {

             @Override
             public void onClick(View arg0) {
                 //通过getActivity方法得到activity的控件，以此可以得到数据
                 EditText eText = (EditText) getActivity().findViewById(
                         R.id.editText2);
                 Log.i("info", "------->" + eText.getText().toString());
                 editText.setText(eText.getText().toString());

             }
         });
         return view;
     }

     @Override
     public void onStart() {
         // TODO Auto-generated method stub
         super.onStart();
     }

     @Override
     public void onResume() {
         // TODO Auto-generated method stub
         super.onResume();
     }

     @Override
     public void onPause() {
         // TODO Auto-generated method stub
         super.onPause();
     }
     //实现数据传递
     public void getString(Callback callback) {
         String msg = editText.getText().toString();
         callback.getString(msg);
     }
     //创建接口
     public interface Callback {
         public void getString(String msg);
     }

 }

main的xml

 "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=".MainActivity" >


         android:id="@+id/left"
         android:layout_width="200dp"
         android:layout_height="match_parent"
         android:background="#cbcbcb"
         android:orientation="vertical" >



         android:id="@+id/right"
          android:layout_width="200dp"
         android:layout_height="match_parent"
         android:orientation="vertical"
         >





         android:id="@+id/editText2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentTop="true"
         android:layout_marginTop="14dp"
         android:layout_toRightOf="@+id/left"
         android:ems="10"
         android:inputType="textPassword" >





         android:id="@+id/button1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@+id/editText2"
         android:layout_toRightOf="@+id/left"
         android:text="得到Fragment的数据" />

fragment的xml

 "1.0" encoding="utf-8"?>
 "http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" >


         android:id="@+id/editText1"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:inputType="text"
         android:ems="10" >





         android:id="@+id/button1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="得到Activity的数据" />

      这样就大功告成了，点击fragment的button就可以在其editText控件显示activity的editText控件的文字，点击activity的button就可以得到fragment的编辑控件的数据！