Android 用openFileOutput 和 openFileInput操作文件

package demo.filerw.service;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import android.content.Context;
import android.os.Environment;
/**
* 文件操作类
* @author janrone
*/
public class FileService {
   private Context context;
   public FileService(Context context) {
       this.context = context;
   }
   //存储数据到文件
   public void saveName(String name) throws Exception{
       //context.getFilesDir();// 得到存放文件的系统目录 /data/data/<package name>/files
       //context.getCacheDir(); //缓存目录  /data/data/<package name>/cache
       FileOutputStream outputStream=context.openFileOutput(“deomfilerw.txt”, Context.MODE_APPEND);
       outputStream.write(name.getBytes());
       outputStream.close();
   }
   //存储数据到sdcard
   public void saveNameToSDCard(String name) throws Exception{
       Environment.getExternalStorageDirectory(); //得到sdcard目录
        File file=new File(“/sdcard”,”demosdcard.txt”);
        FileOutputStream outputStream=new FileOutputStream(file);
        outputStream.write(name.getBytes());
        outputStream.close();
    }
    // 读取数据
    public String getName() throws Exception{
        FileInputStream inputStream=context.openFileInput(“deomfilerw.txt”);
        ByteArrayOutputStream outStream=new ByteArrayOutputStream();
        byte[] buffer=new byte[1024];
        int len=0;
        while ((len=inputStream.read(buffer))!=-1){
            outStream.write(buffer, 0, len);
        }
        outStream.close();
        byte[] data=outStream.toByteArray();
        String name=new String(data);
        return name;
    }
}

package demo.filerw.clicklistener;
import android.app.Activity;
import android.content.Context;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import demo.filerw.R;
import demo.filerw.service.FileService;
public class ClickListener implements OnClickListener {
    private FileService fileService;
    private EditText editText;
    private TextView show_text;
    private Context context;
    public ClickListener(Context context) {
        this.context=context;
        fileService = new FileService(context);
        Activity activity = (Activity) context;
        editText = (EditText) activity.findViewById(R.id.edit_name);
        show_text = (TextView) activity.findViewById(R.id.show_text);
    }
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.ok_button:
            String name=editText.getText().toString();
            try {
                fileService.saveName(name);
                Toast.makeText(context, R.string.ok_succee, Toast.LENGTH_SHORT).show();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                //Toast.makeText(contex, R.string.ok_error, Toast.LENGTH_SHORT).show();
            }
            break;
        case R.id.read_button:
            try {
                String name1 =fileService.getName();
                show_text.setText(name1);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                Toast.makeText(context, R.string.read_error, Toast.LENGTH_SHORT).show();
            }
            break;
        }
    }
}

package demo.filerw;
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
import demo.filerw.clicklistener.ClickListener;
public class FileRWActivity extends Activity {
    private Button ok_button;
    private Button read_button;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ok_button = (Button) findViewById(R.id.ok_button);
        read_button = (Button) findViewById(R.id.read_button);
        ok_button.setOnClickListener(new ClickListener(this));
        read_button.setOnClickListener(new ClickListener(this));
    }
}
main.xml

<?xml version=”1.0″ encoding=”utf-8″?>
<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
    android:layout_width=”fill_parent”
    android:layout_height=”fill_parent”
    android:orientation=”vertical” >
    <TextView
        android:layout_width=”fill_parent”
        android:layout_height=”wrap_content”
        android:text=”@string/hello” />
    <TextView
        android:layout_width=”fill_parent”
        android:layout_height=”wrap_content”
        android:text=”@string/name_lable”
        />
    <EditText
        android:layout_width=”fill_parent”
        android:layout_height=”wrap_content”
        android:id=”@+id/edit_name”
        />
    <LinearLayout
        android:layout_width=”wrap_content”
        android:layout_height=”wrap_content”
        android:orientation=”horizontal” >
        <Button
            android:id=”@+id/ok_button”
            android:layout_width=”fill_parent”
            android:layout_height=”fill_parent”
            android:text=”@string/ok_button”
        />
         <Button
            android:id=”@+id/read_button”
            android:layout_width=”fill_parent”
            android:layout_height=”fill_parent”
            android:text=”@string/read_button”
        />
    </LinearLayout>
        <TextView
            android:id=”@+id/show_text”
            android:layout_width=”fill_parent”
            android:layout_height=”wrap_content”
        />
</LinearLayout>

   <uses-sdk android:minSdkVersion=”10″ />
   <!– 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”/>
<instrumentation
    android:name=”android.test.InstrumentationTestRunner”
    android:targetPackage=”demo.filerw” android:label=”ServiceTest”
    />
   <application
       android:icon=”@drawable/ic_launcher”
       android:label=”@string/app_name” >
       <uses-library android:name=”android.test.runner” />
       <activity
           android:label=”@string/app_name”
           android:name=”.FileRWActivity” >
           <intent-filter >
               <action android:name=”android.intent.action.MAIN” />
               <category android:name=”android.intent.category.LAUNCHER” />
           </intent-filter>
       </activity>
   </application>

package demo.filerw;
import demo.filerw.service.FileService;
import android.os.Environment;
import android.test.AndroidTestCase;
import android.util.Log;
public class FileTest extends AndroidTestCase {
    private static final String TAG=”FileTest”;
    //存储数据
    public void testSaveName() throws Exception{
        FileService fileService=new FileService(this.getContext());
        fileService.saveName(“李明”);
    }
    public void testSaveNameToSDCard() throws Exception{
        if (Environment.getExternalStorageState() == Environment.MEDIA_MOUNTED) {
            FileService fileService = new FileService(this.getContext());
            fileService.saveNameToSDCard(“李明和小强”);
        } else {
            Log.e(TAG, ”sdcard not exsit or only read”);
        }
    }
    public void getSaveName() throws Exception{
        FileService fileService=new FileService(this.getContext());
        String name=fileService.getName();
        Log.i(TAG, name);
    }
}