Android文件读写包含SDCard

package com.xiva.file;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStream;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.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;public class FileActivity extends Activity {private EditText fileName;private EditText content;private TextView textContent;private static final String TAG = "FileActivity";    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        fileName = (EditText) this.findViewById(R.id.fileName);        content  = (EditText) this.findViewById(R.id.content);        textContent = (TextView) this.findViewById(R.id.textContent);        Button saveBtn = (Button)this.findViewById(R.id.saveButton);        Button viewBtn = (Button)this.findViewById(R.id.viewButton);                saveBtn.setOnClickListener(listener);//保存按钮事件监听        viewBtn.setOnClickListener(listener);//查看按钮事件监听    }        private View.OnClickListener listener = new View.OnClickListener(){        public void onClick(View v) {// TODO Auto-generated method stubButton button     = (Button) v;String nameStr    = fileName.getText().toString().trim();        String contentStr = content.getText().toString();        boolean isExsit   = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);        switch(button.getId())        {        case R.id.saveButton :            int resId_s             = R.string.success;            FileOutputStream fileOS = null;    try {//    Context.MODE_APPEND----已append的模式保存文件内容,//    将现在的内容追加到原有文件内容之后//    Context.MODE_PRIVATE：为默认操作模式，代表该文件是私有数据，//    只能被应用本身访问，在该模式下，写入的内容会覆盖原文件的内容//    Context.MODE_WORLD_READABLE和Context.MODE_WORLD_WRITEABLE//    用来控制其他应用是否有权限读写该文件    //如若SD卡存在，文件则存入SD卡    if(isExsit)    {    fileOS = null;    File file     = new File(Environment.getExternalStorageDirectory(), nameStr+".txt");    fileOS        = new FileOutputStream(file);    }    else    {    fileOS  = FileActivity.this.openFileOutput(nameStr+".txt",    Context.MODE_WORLD_READABLE + Context.MODE_WORLD_WRITEABLE + Context.MODE_APPEND);    Toast.makeText(FileActivity.this, "SDCard不存在或者处于保护状态，文件写入手机内存", Toast.LENGTH_LONG).show();    }    FileService.save(fileOS, contentStr);    } catch (Exception e) {    resId_s = R.string.failure;    e.printStackTrace();    }//    界面提示    Toast.makeText(FileActivity.this, resId_s, Toast.LENGTH_LONG).show();    Log.i(TAG, nameStr);    Log.i(TAG, contentStr);    break;        case R.id.viewButton :        int resId_v    = R.string.readSucc;        InputStream fileIS = null;        String contentSt   = null;try {if(isExsit){File file = new File(Environment.getExternalStorageDirectory(), nameStr+".txt");fileIS    = new FileInputStream(file);}else{fileIS    = FileActivity.this.openFileInput(nameStr+".txt");}contentSt = FileService.read(fileIS);} catch (Exception e) {resId_v = R.string.readFail;e.printStackTrace();}textContent.setText(contentSt);Log.i(TAG, contentSt);Toast.makeText(FileActivity.this, resId_v, Toast.LENGTH_LONG).show();break;default: break;        }}           };    }

<!-- 在SDCard中创建与删除文件权限 --><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"/>

在配置文件中的数据权限加入，完整代码见附件！

总结：写入手机内存的文件，权限由程序控制，加入为private，则只可允许本应用访问；而文件在SDCard上的存储，其权限由配置文件，也就是由Android系统根据配置来告知应用！注意，在对SDCard进行操作前，先对其存在性进行判断！

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