android 文件系统操作 文件读取与写入

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_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" >

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:orientation="vertical" >

<EditText
android:id="@+id/editText1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10" >

<requestFocus />
</EditText>

<EditText
android:id="@+id/editText2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minLines="3"
android:ems="10"

/>

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"

android:text="保存文件"
></Button>

<Button
android:id="@+id/readbtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="读取文件" />

<EditText
android:id="@+id/readname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10" />

<TextView
android:id="@+id/neirongxianshi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView" />

"

"

</LinearLayout>

</RelativeLayout>

package com.example.mytool;

import com.example.service.FileService;

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

public class MainActivity extends Activity {
private EditText mytext;//寻找空间这种事情只需要做一次就够了
private EditText duanxin;
private EditText mfilename;
private TextView xianshinr;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mytext = (EditText) findViewById(R.id.editText1);//得到文本输入框
duanxin=(EditText)this.findViewById(R.id.editText2);
Button button = (Button) this.findViewById(R.id.button1);//根据id寻找控件
button.setOnClickListener(new ButtonClick());//添加点击事件
Button readbtn=(Button)this.findViewById(R.id.readbtn);
readbtn.setOnClickListener(new Mybtnclick());
mfilename=(EditText)this.findViewById(R.id.readname);
xianshinr=(TextView)this.findViewById(R.id.neirongxianshi);
}
private final class Mybtnclick implements View.OnClickListener{

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
FileService duqu=new FileService(getApplicationContext());
String fname=mfilename.getText().toString();
try {
String filestr=duqu.read(fname);
xianshinr.setText(filestr);
Toast.makeText(getApplicationContext(), "读取成功", Toast.LENGTH_LONG).show();
} catch (Exception e) {
// TODO Auto-generated catch block
Toast.makeText(getApplicationContext(), "失败", Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}

}

private final class ButtonClick implements View.OnClickListener{

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String mobileText = mytext.getText().toString();
String content=duanxin.getText().toString();
FileService oj=new FileService(getApplicationContext());
try{
oj.save(mobileText, content);
Toast.makeText(getApplicationContext(), "保存成功", Toast.LENGTH_LONG).show();
}catch(Exception e){
Toast.makeText(getApplicationContext(), "保存失败", Toast.LENGTH_LONG).show();

}

}

}

@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;
}

}

package com.example.service;

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

import android.content.Context;

public class FileService {
private final Context context;

public FileService(Context context) {
this.context = context;
}

public void save(String filename,String content) throws Exception{
FileOutputStream infile=context.openFileOutput(filename, context.MODE_PRIVATE);
infile.write(content.getBytes());
infile.close();
}

public String read(String filaname) throws Exception{
FileInputStream rfile = context.openFileInput(filaname);
ByteArrayOutputStream neicun = new ByteArrayOutputStream();
byte[] buf=new byte[1024];
int len=0;
while((len=rfile.read(buf))!=-1){
neicun.write(buf, 0, len);
}
rfile.close();
neicun.close();
String restr=new String(buf,"GBK");
return restr;
}

}

InputStream infile=context.getAssets().open(fname);
int len=infile.available();
byte[] str=new byte[len];
infile.read(str);
infile.close();
return new String(str,"utf-8");