布局文件==》

<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=".MainActivity" >

    <EditText

        android:id="@+id/edit1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

    <Button

        android:id="@+id/btnone"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="write" />

    <EditText

        android:id="@+id/edit2"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

    <Button

        android:id="@+id/btnTwo"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="read" />

</LinearLayout>

代码实现==》

package com.example.myfile;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.PrintStream;

import android.os.Bundle;

import android.app.Activity;

import android.util.Log;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

public class MainActivity extends Activity

{

	final String FILE_NAME = "crazyit.bin";

	EditText Edit1;

	EditText Edit2;

	@Override

	protected void onCreate(Bundle savedInstanceState)

	{

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		Button btnOne = (Button) this.findViewById(R.id.btnone);

		Button btnTwo = (Button) this.findViewById(R.id.btnTwo);

		Edit1 = (EditText) this.findViewById(R.id.edit1);

		Edit2 = (EditText) this.findViewById(R.id.edit2);

		btnOne.setOnClickListener(new MyButtonClick());

		btnTwo.setOnClickListener(new MyButtonClick());

	}

	private class MyButtonClick implements OnClickListener

	{

		@Override

		public void onClick(View v)

		{

			switch (v.getId())

			{

			case R.id.btnone:

				Log.i("swg", "write==" +Edit1.getText());

				write(Edit1.getText().toString());

				Edit1.setText("");

				break;

			case R.id.btnTwo:

				Log.i("swg", "read==" +read());

				Edit2.setText(read());

				break;

			}

		}

		private String read()

		{

			try

			{

				FileInputStream fis = openFileInput(FILE_NAME);

				byte[] buff = new byte[1024];

				int hasread = 0;

				StringBuilder sb = new StringBuilder("");

				while ((hasread = fis.read(buff)) > 0)

				{

					sb.append(new String(buff, 0, hasread));

				}

				return sb.toString();

			} catch (Exception e)

			{

				e.printStackTrace();

			}

			return null;

		}

		private void write(String content)

		{

			try

			{

				// 以追加模式打开文件输出流

				FileOutputStream fos = openFileOutput(FILE_NAME, MODE_APPEND);

				// 将FileOutputStream包装成PrintStream

				PrintStream ps = new PrintStream(fos);

				// 输出文件内容

				ps.println(content);

				ps.close();

			} catch (Exception e)

			{

				e.printStackTrace();

			}

		}

	}

	@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;

	}

}