安卓文件的读和写的实现

说明：

文件保存路径为安卓默认路径,/data/应用包名(全名)/files

一、activity

package com.example.filerw;

import com.example.server.FileServer;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
	private EditText contentEdit;
	private String file_name="file.txt";
	private FileServer fileServer;
	private TextView showText;

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		contentEdit = (EditText)findViewById(R.id.content);
		showText = (TextView)findViewById(R.id.showText);

		fileServer = new FileServer(getApplicationContext());
	}

	public void MainClick(View v){
		switch (v.getId()) {
		case R.id.save:
			String str = contentEdit.getText().toString();
			fileServer.save(file_name, str);
			break;

		case R.id.read:
			String show = fileServer.read(file_name);
			showText.setText(show);
			break;

		default:
			break;
		}
	}
	//菜单
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
}

二、主要实现代码

package com.example.server;

import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

import org.apache.http.util.EncodingUtils;

import android.content.Context;

public class FileServer {
	private Context context;
	private FileInputStream in;
	private FileOutputStream out;

	public FileServer(Context context){
		this.context = context;
	}
	/**
	 * 保存
	 * @param name
	 */
	public void save(String name,String content){
		try {
			out = context.openFileOutput(name, Context.MODE_PRIVATE);
			out.write(content.getBytes());
			out.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (Exception e) {
			System.out.println(e.toString());
		}
	}
	/**
	 * 读文件
	 * @param name
	 * @return
	 */
	public String read(String name){
		String file_content = null;
		try {
			ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
			in = context.openFileInput(name);//具有缓冲实例的打开文件
			byte[] buf = new byte[1024];
			while((in.read(buf))!=-1){
				byteOut.write(buf);//将读出来的数据写到缓存中
			}
			file_content = EncodingUtils.getString(byteOut.toByteArray(),"GBK");//转码

			byteOut.close();
			in.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}catch (Exception e) {
			System.out.println(e.toString());
		}
		return file_content;
	}
}

三、xml

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:padding="0dp"
    >
    <EditText
        android:id="@+id/content"
  		android:inputType="text"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="请输入内容"
        android:textSize="16sp"
        android:background="@drawable/edit_xmlbg"
        android:minHeight="30dp"
        />
    <TextView
        android:id="@+id/showText"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/content"
        />
    <Button
        android:id="@+id/save"
        android:onClick="MainClick"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:text="save"
        android:layout_alignParentBottom="true"
        />
	<Button
        android:id="@+id/read"
        android:onClick="MainClick"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:text="read"
        android:layout_alignParentBottom="true"
        android:layout_toRightOf="@+id/save"
        />
</RelativeLayout>

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