android sd卡读写 附源码

将文件存在sd卡中和存在手机中的思路相同就是路径不同,注意看类中的到sd卡路径的注释

package cn.lee.data;

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

import cn.lee.Manager.DataManager;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class AboutDateActivity extends Activity {
	private EditText fileNameEditText;
	private EditText fileContentEditText;
	private EditText readfileContentEditText;
	private Button button;
	private Button readButton;
	private static final String TAGSTRING = "AboutDateActivity";

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		button = (Button) this.findViewById(R.id.button);
		readButton = (Button) this.findViewById(R.id.readButton);
		fileNameEditText = (EditText) this.findViewById(R.id.fileName);
		fileContentEditText = (EditText) this.findViewById(R.id.fileContent);
		readfileContentEditText = (EditText) this
				.findViewById(R.id.readfileContent);

		// 读取
		readButton.setOnClickListener(onClickListener);
		// 保存
		button.setOnClickListener(onClickListener);
	}

	/**
	 * 由于这个内部实现类是一个接口的实例 所以这里把他提取出来 作为一个成员变量 2010-04-18
	 */
	private View.OnClickListener onClickListener = new View.OnClickListener() {
		/**
		 * 由于button的父类是view 所以这里的onclick的参数传来的view v就可以找到这个button
		 */
		public void onClick(View v) {
			Button button = (Button) v;// 将父类view强转成子类button
			int info = R.string.sus;
			String fileNameString = fileNameEditText.getText().toString();
			
			/**
			 * 判断sd卡是否存在 Environment.getExternalStorageState() 得到sd卡当前的状态
			 * 
			 * getExternalStorageState() returns MEDIA_MOUNTED if the
			 * media is present and mounted at its mount point with
			 * read/write access. 如果返回 MEDIA_MOUNTED表示外部存储设备存在。并且有读写的权限(因为sd卡有写保护 如果写保护关闭也是没有权限读写的)
			 */
			
			if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
				if ("".equals(fileNameString)) {
					info = R.string.sdNotExit;
				} else {
					FileOutputStream fileOutputStream = null;
					FileInputStream fileInputStream = null;
					try {
						/**
						 * Environment.getExternalStorageDirectory();
						 * 得到外存储设备的路径
						 * 
						 */
						File file = new File(Environment.getExternalStorageDirectory(),fileNameString);
						
						switch (button.getId()) {
						case R.id.button: {// 保存
							String fileContentString = fileContentEditText.getText().toString();
							
							fileOutputStream = new FileOutputStream(file);
							DataManager.saveDate(fileOutputStream,fileContentString);
							break;
						}

						case R.id.readButton: {//读取
							fileInputStream = new FileInputStream(file);
							String contentString = DataManager.readDate(fileInputStream);
							readfileContentEditText.setText(contentString);
							break;
						}
						default:
							break;
						}

					} catch (Exception e) {
						// TODO Auto-generated catch block
						Log.i(TAGSTRING, e.toString());
						info = R.string.infor;
					} finally {
						try {
							if (fileOutputStream != null) {
								fileOutputStream.close();
							}
							if (fileInputStream != null) {
								fileInputStream.close();
							}

						} catch (IOException e) {

							Log.i(TAGSTRING, e.toString());
							info = R.string.infor;
						}
					}

				}
			} else {
				info = R.string.infor;
			}
			Toast.makeText(AboutDateActivity.this, info, 1).show();
		}

	};
}

评论

2 楼 lina3427 2012-03-23  

好文章，谢谢朋友

1 楼 jiangsuwwj 2012-02-25  

好文章，写的不错，赞一个。