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文件
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，如果想把新写入的内容追加到原文件中。可以使用Context.MODE_APPEND
Context.MODE_APPEND：模式会检查文件是否存在，存在就往文件追加内容，否则就创建新文件。
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。
MODE_WORLD_READABLE：表示当前文件可以被其他应用读取；MODE_WORLD_WRITEABLE：表示当前文件可以被其他应用写入。
如果希望文件被其他应用读和写，可以传入：
openFileOutput("itcast.txt", Context.MODE_WORLD_READABLE + Context.MODE_WORLD_WRITEABLE);
/**
* @author
* @文件操作类：新建文件、删除、读写
* */
package com.gogler.gps.infor;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import android.content.Context;
import android.os.Environment;
public class FileHelper
{
private final Context context;
/** SD卡是否存在 **/
private boolean hasSD = false;
/** SD卡的路径 **/
private final String SDPATH;
/** 当前程序包的路径 **/
private final String FILESPATH;
/**
* 从调用者传入
* @param Context like this.getApplicationContext()
*
*
* */
public FileHelper ( Context context )
{
this.context = context;
hasSD = Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED);
SDPATH = Environment.getExternalStorageDirectory().getPath();
FILESPATH = this.context.getFilesDir().getPath();
}
/**
*
* 在SD卡上创建文件
*
*
*
* @throws IOException
*/
public File createSDFile(String fileName) throws IOException
{
final File file = new File(SDPATH + "//" + fileName);
if (!file.exists())
{
file.createNewFile();
}
return file;
}
/**
*
* 删除SD卡上的文件
*
*
* @param fileName
*/
public boolean deleteSDFile(String fileName)
{
final File file = new File(SDPATH + "//" + fileName);
if ((file == null) || !file.exists() || file.isDirectory())
{
return false;
}
return file.delete();
}
public String getFILESPATH()
{
return FILESPATH;
}
public String getSDPATH()
{
return SDPATH;
}
public boolean hasSD()
{
return hasSD;
}
/**
*
* 读取SD卡中文本文件
*
*
*
* @param fileName
*
* @return String
*/
public String readSDFile(String fileName)
{
final StringBuffer sb = new StringBuffer();
final File file = new File(SDPATH + "//" + fileName);
try
{
final FileInputStream fis = new FileInputStream(file);
int c;
while ((c = fis.read()) != -1)
{
sb.append((char) c);
}
fis.close();
}
catch (final FileNotFoundException e)
{
e.printStackTrace();
}
catch (final IOException e)
{
e.printStackTrace();
}
return sb.toString();
}
/**
*
*
* 写SD卡上的文件
*
*
* @param String
* fileName,String content
*
*
* @return boolean
*
*
* @author Administrator
*/
public boolean writeFileData(String fileName, String content)
{
try
{
final FileOutputStream fout = new FileOutputStream(SDPATH + "//"
+ fileName, true);
final PrintStream ps = new PrintStream(fout);
ps.println(content);
ps.close();
}
catch (final IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return true;
}
}
l
SharedPreferences
创建可跨程序使用的Preferrence
package com.gogler.SharePreferences;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.content.res.Resources;
import android.os.Bundle;
public class SharePreferencesTestActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 使用可跨程序读写的Preference
SharedPreferences sp = getSharedPreferences("hello", Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE);
Editor editor = sp.edit();
String str = "SharePreferencesTestActivity: "+getResources().getString(R.string.hello);
editor.putString("helloStr", str );
editor.commit();
}
}
读取其他APP的Preference
package sharePreferences.gogler.com;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Bundle;
import android.widget.TextView;
public class UseSharePreferencesTestActivity extends Activity {
final String packageName = "com.gogler.SharePreferences";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 访问其他APP的Preference
try {
Context otherAppContext = createPackageContext(packageName, Context.CONTEXT_IGNORE_SECURITY);
SharedPreferences sp = otherAppContext.getSharedPreferences("hello", Context.MODE_WORLD_READABLE);
TextView tv=(TextView)findViewById(R.id.tv);
tv.setText(sp.getString("helloStr", ""));
} catch (NameNotFoundException e) {
e.printStackTrace();
}
}
}
