android I/o 例子 | 红颜丽人

http://www.blogjava.net/freeman1984/archive/2009/11/08/android-io.html android里面读取文件地方法基本和java中一样，使用流来读取，只是文件的存放有些规定而已。 android程序是有文件目录为：/data/data/<包名>/files/ 例如：final String filename = “data/data/com.iotest/iotest.txt”; 如果有定义错误就会出现错误。下面是一个简单的例子说明：首先是我们的layout： main.xml:

<?xml version=”1.0″ encoding=”utf-8″?>

<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”

android:orientation=”vertical” android:layout_width=”fill_parent”

android:layout_height=”fill_parent”>

<Button android:text=”write text” android:id=”@+id/write”

android:layout_width=”fill_parent”

android:layout_height=”wrap_content”

</Button>

<Button android:text=”read text” android:id=”@+id/read”

android:layout_width=”fill_parent”

android:layout_height=”wrap_content”

</Button>

<EditText android:text=”text to insert into file

..”

android:id=”@+id/EditText01″ android:layout_width=”fill_parent”

android:layout_height=”fill_parent”>

</EditText>

</LinearLayout>

最后生成的界面为如下：然后使我们的activity：

package com.iotest;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import org.apache.http.util.EncodingUtils;

import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

public class IoTest extends Activity implements OnClickListener

{

/** *//** Called when the activity is first created. */

final String filename = “data/data/com.iotest/iotest.txt”;

final String tag=”I/O”;

EditText editText;

Button buttonw;

Button buttonr;

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

editText = (EditText)findViewById(R.id.EditText01);

buttonr = (Button)findViewById(R.id.read);

buttonw = (Button)findViewById(R.id.write);

buttonr.setOnClickListener(this);

buttonw.setOnClickListener(this);

}

public void onClick(View v)

{

switch (v.getId())

{

case R.id.read:

readTest();

break;

case R.id.write:

writeTest();

default:

break;

}

public void writeTest()

{

try

{

File file = new File(filename);

file.createNewFile();

Log.d(tag, “create flie!”);

BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(file));

bufferedOutputStream.write(editText.getText().toString().getBytes());

bufferedOutputStream.close();

}catch (Exception e)

{

Log.e(tag, “error in write”);

}

public void readTest()

{

try

{

File file = new File(filename);

BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(file));

byte[] data = new byte[(int) file.length()];

bufferedInputStream.read(data);

String str = EncodingUtils.getString(data, “utf-8″);

bufferedInputStream.close();

editText.setText(“读取到的数据：”+str);

} catch (Exception e)

{

// TODO Auto-generated catch block

Log.e(tag, “error in read”);

}

也就是要注意下文件的路径。

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