操作SD卡上的文本文件

代码是没有在AndroidMenifest.xml中设置权限的前提下对SD卡上的文件进行写,删除操作的例子:
奉上代码:

package cn.com;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;

public class SdCardEx extends Activity implements OnClickListener {
	File file;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		Button delete = (Button) findViewById(R.id.delete);
		delete.setOnClickListener(this);

		file = new File("/sdcard/1.txt");
		
		//判断文件是否存在
		if (file.exists()) {
			System.out.println("file exists");
			try {
				FileOutputStream fos = new FileOutputStream("/sdcard/1.txt");
				fos.write("Hello World!".getBytes());
				fos.flush();
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} else {
			try {
				file.createNewFile();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		if (file.exists()) {
			file.delete();
		}
	}
}

2.main.xml文件布局

<?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">
	<TextView android:layout_width="fill_parent"
		android:layout_height="wrap_content" android:text="@string/hello" />
	<Button android:layout_width="wrap_content"
		android:layout_height="wrap_content" android:text="delete" android:id="@+id/delete" />
</LinearLayout>