向sd卡写文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<EditText
android:id="@+id/numET"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="请输入文件名" />

<EditText
android:id="@+id/contentET"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="请输入文件内容"
android:inputType="textMultiLine"
android:minLines="3" />

<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >

<Button android:id="@+id/sdcBT"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="保存到sd卡"
android:onClick="onClick"
/>

<Button android:id="@+id/romBT"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="保存到手机"
android:onClick="onClick"
/>
</LinearLayout>

</LinearLayout>

package com.example.writeintosdcard;

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

public class MainActivity extends Activity {

private EditText numET;// 文件名
private EditText contentET;// 文件内容3行

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

numET = (EditText) findViewById(R.id.numET);
contentET = (EditText) findViewById(R.id.contentET);

}

@Override
protected void onResume() {
super.onResume();

// Environment.getExternalStorageState().获取sd卡的状态，根据sd卡是否挂载判断是安装，还是移除
findViewById(R.id.sdcBT).setEnabled(
Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED));
}

@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 onClick(View v) {
try {
String name = numET.getText().toString();
String content = contentET.getText().toString();

FileService service = new FileService();

switch (v.getId()) {
case R.id.sdcBT://保存到sd卡

service.saveToSDCard(name, content);
break;

case R.id.romBT://保存到手机

service.saveToRom(name, content);//保存到手机什么也执行
break;
}

Toast.makeText(getApplicationContext(), "保存成功", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(getApplication(), "SDcard出异常", Toast.LENGTH_SHORT).show();
}
}

}

package com.example.writeintosdcard;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import android.os.Environment;

public class FileService {

public void saveToSDCard(String name, String content) {

FileOutputStream fos = null;

try {

// Environment.getExternalStorageDirectory()。获取sd卡的路径
File file = new File(Environment.getExternalStorageDirectory(),name);
fos = new FileOutputStream(file);

fos.write(content.getBytes());
} catch (Exception e) {

e.printStackTrace();

} finally {

try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

public void saveToRom(String name, String content) {
// TODO Auto-generated method stub

}

}