将文件存入SDCard

首先，SDCard所在的路径：

/mnt/sdcard android2.2

/sdcard android2.2版本之前 /sdcard-à/mnt/sdcard 用哪个都可以，镜像

业务层代码：

public void saveToSDCard(String filename, String filecontent)
			throws IOException {
		// 建议不要使用绝对路径
		//File file = new File("/mnt/sdcard", filename);
		System.out.println(Environment.getExternalStorageDirectory());
		File file=new File(Environment.getExternalStorageDirectory(),filename);
		FileOutputStream fos = new FileOutputStream(file);// 创建文件输出流
		fos.write(filecontent.getBytes());
		fos.close();
	}

MainActivity.java代码：

 

package cn.bzu.fileoperation;

import java.io.IOException;

import cn.bzu.service.FileService;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.support.v4.app.NavUtils;

public class MainActivity extends Activity {
	private FileService fileService;
	private Button saveButton;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		fileService = new FileService(this);
		saveButton = (Button) this.findViewById(R.id.save);
		saveButton.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				EditText fileNameText = (EditText) findViewById(R.id.filename);
				EditText fileContentText = (EditText) findViewById(R.id.filecontent);
				String fileName = fileNameText.getText().toString();
				String fileContent = fileContentText.getText().toString();
				if (Environment.getExternalStorageState().equals(
						Environment.MEDIA_MOUNTED)) {
					try {

						fileService.saveToSDCard(fileName, fileContent);
						Toast.makeText(MainActivity.this, R.string.success,
								Toast.LENGTH_LONG).show();
					} catch (IOException e) {
						e.printStackTrace();
						Toast.makeText(MainActivity.this, R.string.failure,
								Toast.LENGTH_LONG).show();
					}
				}else{
					Toast.makeText(MainActivity.this, R.string.sdcarderror, Toast.LENGTH_LONG).show();
				}
			}
		});
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.activity_main, menu);
		return true;
	}

}

AndroidManifest.xml中设置权限：

 <!-- 创建文件删除文件权限 -->
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
    <!-- 往SDCard写入数据权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />