保存密码到SD卡

<pre name="code" class="java"><span style="font-size:18px;">package com.melody.savepasswd.sd;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;

import com.melody_savepasswd_sd.R;



import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

	private EditText et_name;
	private EditText et_passwd;
	private CheckBox cb;
	private FileOutputStream fos;
	private FileInputStream fis;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		init();
		readAccount();
		
		
		
	}
	
	//读取进度方法
	private void readAccount() {		
		//读取文件，回显数据
		File file = new File(Environment.getExternalStorageDirectory(),"info.txt");
		if(file.exists()){
			try {
				fis = new FileInputStream(file);
				//把字节流转换成字符流
				BufferedReader br = new BufferedReader(new InputStreamReader(fis));
				//读出来的数据存入到文本     一行一行读
				String text = br.readLine();
				//回显数据    split  字符切割
				String s[] = text.split("&&");
				//给输入框设置文本
				et_name.setText(s[0]);
				et_passwd.setText(s[1]);
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			}finally{
				if(fis != null){
					try {
						fis.close();
					} catch (IOException e) {
						e.printStackTrace();
					}
				}
			}
		}
		
	}

	private void init() {
		et_name = (EditText) findViewById(R.id.et_name);
		et_passwd = (EditText) findViewById(R.id.et_passwd);
		cb = (CheckBox) findViewById(R.id.cb);
	}
	
	public void login(View v){
		//获取用户名和密码
		String name = et_name.getText().toString();
		String passwd = et_passwd.getText().toString();

		//判断复选框是否选中
	
		/**
		 * ###外部存储路径
		 * 2.2之前：sdcard
		 *2.2~4.2：mnt/sdcard
		 *4.3开始：storage/sdcard
		 */
		
		if(cb.isChecked()){
			//File file = new File("sdcard/login.txt");
			//MEDIA_REMOVED:SD卡移除
			//MEDIA_UNMOUNTED:SD卡存在，但是没挂载
			if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
				//返回一个File对象，封装一个真实的外部路径
				File file = new File(Environment.getExternalStorageDirectory(),"info.txt");
				try {
					fos = new FileOutputStream(file);
					//把帐号和密码写如文件
					fos.write((name+"&&"+passwd).getBytes());
				} catch (FileNotFoundException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				}finally{
					if(fos != null){
						try {
							fos.close();
						} catch (IOException e) {
							e.printStackTrace();
						}
					}
				}
			}else{
				Toast.makeText(this, "SD卡不可用", 0).show();
			}
			
		}
		Toast.makeText(this, "登录成功", 0).show();
	}
}
</span>