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;

	@Override
	protected 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() {

			@Override
			public 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string
				FragmentManager 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 {
	@Override
	public 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;

	@Override
	protected 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() {

			@Override
			public 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string
				FragmentManager 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();

			}
		});
	}

	@Override
	public 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);
	}
	
	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		listener=(MyListener) activity;
	}
	@Override
	public 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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