android之文件读写实例测试 java程序员

package com.example.file;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import android.os.Bundle;
import android.app.Activity;
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 {

	private final static String FILE_NAME="temp.txt";
	private EditText et1,et2;
	private Button b1,b2;
	@Override
	protected void onCreate(Bundle savedInstanceState) 
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		et1=(EditText)findViewById(R.id.et1);
		et2=(EditText)findViewById(R.id.et2);
		b1=(Button)findViewById(R.id.b1);
		b2=(Button)findViewById(R.id.b2);
		b1.setOnClickListener(new OnClickListener()
		{
			public void onClick(View view)
			{
				write(et1.getText().toString());
			}
		});
		b2.setOnClickListener(new OnClickListener()
		{
			public void onClick(View view)
			{
				et2.setText(read());
			}
		});
	}@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;
	}
	public void write(String content)
	{
		try
		{
			FileOutputStream fos=openFileOutput(FILE_NAME,MODE_APPEND);
			fos.write(content.getBytes());
			fos.close();//note
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		
	}
	public String read()
	{
		try
		{
			FileInputStream fis=openFileInput(FILE_NAME);
			byte[]Buffer=new byte[fis.available()];
			fis.read(Buffer);
			return new String(Buffer);
		}
		catch(IOException e)
		{
			e.printStackTrace();
		}
		return null;//note
	}
}

程序运行截图：

 

注意：向文件写入数据时，之前写入的数据不会被覆盖，新写入的数据将会出现在已写数据之后