Android实战简易教程-第五十二枪（Fragment和Activity之间通信）

Fragment的使用可以让我们的应用更灵活的适配各种型号的安卓设备，但是对于Fragment和Activity之间的通信，很多朋友应该比较陌生，下面我们就通过一个实例来看一看如何实现。

一、Activity->Fragment传递数据

1.main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:id="@+id/rl_fragment"    android:orientation="vertical"    android:layout_height="match_parent" >    <EditText        android:id="@+id/et_input"        android:layout_width="match_parent"        android:layout_height="wrap_content" />    <Button        android:id="@+id/btn_send"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="发送" /></LinearLayout>

2.fragment.xml:

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

3.MainActivity.java:

package com.example.fragementcommunication;import android.app.Activity;import android.app.FragmentManager;import android.app.FragmentTransaction;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity {private EditText mMainActivityET;private Button mSendButton;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);mMainActivityET = (EditText) findViewById(R.id.et_input);mSendButton = (Button) findViewById(R.id.btn_send);mSendButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String text = mMainActivityET.getText().toString();MyFragment myFragment = new MyFragment();Bundle bundle = new Bundle();bundle.putString("input", text);myFragment.setArguments(bundle);// 传递stringFragmentManager manager = getFragmentManager();FragmentTransaction transaction = manager.beginTransaction();transaction.add(R.id.rl_fragment, myFragment, "myfragment");transaction.commit();Toast.makeText(MainActivity.this, "向Fragment发送数据" + text, Toast.LENGTH_SHORT).show();}});}}

4.MyFragment.java:

package com.example.fragementcommunication;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import android.widget.Toast;public class MyFragment extends Fragment {@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {View view = inflater.inflate(R.layout.fragmet, null);TextView mFragmentTextView = (TextView) view.findViewById(R.id.tv_fragment);String string = getArguments().getString("input");// 获取数据；mFragmentTextView.setText(string);Toast.makeText(getActivity(), "成功获取数据" + string, Toast.LENGTH_SHORT).show();return view;}}

总结：发送数据方法->setArguments(bundle)

            接收数据方法->getArguments()

下面我们看一下效果：

二、Fragment向Activity传值（接口回调的方式）

布局文件和上面一样，我们看一下java代码的改变：

1.MainActivity.java:

package com.example.fragementcommunication;import com.example.fragementcommunication.MyFragment.MyListener;import android.app.Activity;import android.app.FragmentManager;import android.app.FragmentTransaction;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity implements MyListener{private EditText mMainActivityET;private Button mSendButton;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);mMainActivityET = (EditText) findViewById(R.id.et_input);mSendButton = (Button) findViewById(R.id.btn_send);mSendButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String text = mMainActivityET.getText().toString();MyFragment myFragment = new MyFragment();Bundle bundle = new Bundle();bundle.putString("input", text);myFragment.setArguments(bundle);// 传递stringFragmentManager manager = getFragmentManager();FragmentTransaction transaction = manager.beginTransaction();transaction.add(R.id.rl_fragment, myFragment, "myfragment");transaction.commit();Toast.makeText(MainActivity.this, "向Fragment发送数据" + text, Toast.LENGTH_SHORT).show();}});}@Overridepublic void callback(String back) {Toast.makeText(MainActivity.this, "获取到从Fragment中传来的数据" + back, Toast.LENGTH_SHORT).show();}}

2.MyFragment.java:

package com.example.fragementcommunication;import android.app.Activity;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import android.widget.Toast;public class MyFragment extends Fragment {public MyListener listener;private String back="已经接收到数据！谢谢";/** * 通过接口回调的方式从Fragment向activity传值； * @author Administrator * */public interface MyListener{public void callback(String back);}@Overridepublic void onAttach(Activity activity) {super.onAttach(activity);listener=(MyListener) activity;}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {View view = inflater.inflate(R.layout.fragmet, null);TextView mFragmentTextView = (TextView) view.findViewById(R.id.tv_fragment);String string = getArguments().getString("input");// 获取数据；mFragmentTextView.setText(string);Toast.makeText(getActivity(), "成功获取数据" + string, Toast.LENGTH_SHORT).show();Toast.makeText(getActivity(), "向Activity传递数据" + back, Toast.LENGTH_SHORT).show();listener.callback(back);return view;}}

运行如下：

这时我们可以看到先是MainActivity向Fragment传递了123，然后Fragment向Activity传递了”已经接收到数据！谢谢“。

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