blocks|key|1270025|text|From+here:+http://www.anddev.org/working_with_files-t115.html|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1270026|//Writing+a+file...++



try+{+
+++++++//+catches+IOException+below
+++++++final+String+TESTSTRING+=+new+String("Hello+Android");
++++++
+++++++/*+We+have+to+use+the+openFileOutput()-method
+++++++*+the+ActivityContext+provides,+to
+++++++*+protect+your+file+from+others+and
+++++++*+This+is+done+for+security-reasons.
+++++++*+We+chose+MODE_WORLD_READABLE,+because
+++++++*++we+have+nothing+to+hide+in+our+file+*/+++++++++++++
+++++++FileOutputStream+fOut+=+openFileOutput("samplefile.txt",
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++MODE_PRIVATE);
+++++++OutputStreamWriter+osw+=+new+OutputStreamWriter(fOut);+

+++++++//+Write+the+string+to+the+file
+++++++osw.write(TESTSTRING);

+++++++/*+ensure+that+everything+is
++++++++*+really+written+out+and+close+*/
+++++++osw.flush();
+++++++osw.close();

//Reading+the+file+back...

+++++++/*+We+have+to+use+the+openFileInput()-method
++++++++*+the+ActivityContext+provides.
++++++++*+Again+for+security+reasons+with
++++++++*+openFileInput(...)+*/
+++++++
++++++++FileInputStream+fIn+=+openFileInput("samplefile.txt");
++++++++InputStreamReader+isr+=+new+InputStreamReader(fIn);
++++++++
++++++++/*+Prepare+a+char-Array+that+will
+++++++++*+hold+the+chars+we+read+back+in.+*/
++++++++char[]+inputBuffer+=+new+char[TESTSTRING.length()];

++++++++//+Fill+the+Buffer+with+data+from+the+file
++++++++isr.read(inputBuffer);

++++++++//+Transform+the+chars+to+a+String
++++++++String+readString+=+new+String(inputBuffer);
+++++++++++++++++++
++++++++//+Check+if+we+read+back+the+same+chars+that+we+had+written+out
++++++++boolean+isTheSame+=+TESTSTRING.equals(readString);

++++++++Log.i("File+Reading+stuff",+"success+=+"+%2B+isTheSame);

++++}+catch+(IOException+ioe)+
++++++{ioe.printStackTrace();}|code-block|syntax|javascript|1270027|entityMap|0|LINK|mutability|MUTABLE|url|http://www.anddev.org/working_with_files-t115.html^0|0|1P|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<a href="http://www.anddev.org/working_with_files-t115.html" rel="nofollow noreferrer">From here: http://www.anddev.org/working_with_files-t115.html</a>
<pre><code>//Writing a file... 



try { 
 // catches IOException below
 final String TESTSTRING = new String(&quot;Hello Android&quot;);
 
 /* We have to use the openFileOutput()-method
 * the ActivityContext provides, to
 * protect your file from others and
 * This is done for security-reasons.
 * We chose MODE_WORLD_READABLE, because
 * we have nothing to hide in our file */ 
 FileOutputStream fOut = openFileOutput(&quot;samplefile.txt&quot;,
 MODE_PRIVATE);
 OutputStreamWriter osw = new OutputStreamWriter(fOut); 

 // Write the string to the file
 osw.write(TESTSTRING);

 /* ensure that everything is
 * really written out and close */
 osw.flush();
 osw.close();

//Reading the file back...

 /* We have to use the openFileInput()-method
 * the ActivityContext provides.
 * Again for security reasons with
 * openFileInput(...) */
 
 FileInputStream fIn = openFileInput(&quot;samplefile.txt&quot;);
 InputStreamReader isr = new InputStreamReader(fIn);
 
 /* Prepare a char-Array that will
 * hold the chars we read back in. */
 char[] inputBuffer = new char[TESTSTRING.length()];

 // Fill the Buffer with data from the file
 isr.read(inputBuffer);

 // Transform the chars to a String
 String readString = new String(inputBuffer);
 
 // Check if we read back the same chars that we had written out
 boolean isTheSame = TESTSTRING.equals(readString);

 Log.i(&quot;File Reading stuff&quot;, &quot;success = &quot; + isTheSame);

 } catch (IOException ioe) 
 {ioe.printStackTrace();}
</code></pre>

blocks|key|1484636|text|我使用以下代码创建了一个用于写入字节的临时文件。而且它工作得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1484637|File+file+=+new+File(Environment.getExternalStorageDirectory()+%2B+"/"+%2B+File.separator+%2B+"test.txt");
file.createNewFile();
byte[]+data1={1,1,0,0};
//write+the+bytes+in+file
if(file.exists())
{
+++++OutputStream+fo+=+new+FileOutputStream(file);++++++++++++++
+++++fo.write(data1);
+++++fo.close();
+++++System.out.println("file+created:+"%2Bfile);
}+++++++++++++++

//deleting+the+file+++++++++++++
file.delete();
System.out.println("file+deleted");|code-block|syntax|javascript|1484638|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I used the following code to create a temporary file for writing bytes. And its working fine.

<pre><code>File file = new File(Environment.getExternalStorageDirectory() + "/" + File.separator + "test.txt");
file.createNewFile();
byte[] data1={1,1,0,0};
//write the bytes in file
if(file.exists())
{
 OutputStream fo = new FileOutputStream(file); 
 fo.write(data1);
 fo.close();
 System.out.println("file created: "+file);
} 

//deleting the file 
file.delete();
System.out.println("file deleted");
</code></pre>

blocks|key|1484728|text|我决定从这个线程中编写一个可能对其他人有帮助的类。请注意，这当前仅用于写入"files“目录(例如，不写入"sdcard”路径)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1484729|import+java.io.BufferedReader;
import+java.io.FileInputStream;
import+java.io.FileOutputStream;
import+java.io.IOException;
import+java.io.InputStreamReader;
import+java.io.OutputStreamWriter;

import+android.content.Context;

public+class+AndroidFileFunctions+{

++++public+static+String+getFileValue(String+fileName,+Context+context)+{
++++++++try+{
++++++++++++StringBuffer+outStringBuf+=+new+StringBuffer();
++++++++++++String+inputLine+=+"";
++++++++++++/*
+++++++++++++*+We+have+to+use+the+openFileInput()-method+the+ActivityContext
+++++++++++++*+provides.+Again+for+security+reasons+with+openFileInput(...)
+++++++++++++*/
++++++++++++FileInputStream+fIn+=+context.openFileInput(fileName);
++++++++++++InputStreamReader+isr+=+new+InputStreamReader(fIn);
++++++++++++BufferedReader+inBuff+=+new+BufferedReader(isr);
++++++++++++while+((inputLine+=+inBuff.readLine())+!=+null)+{
++++++++++++++++outStringBuf.append(inputLine);
++++++++++++++++outStringBuf.append("\n");
++++++++++++}
++++++++++++inBuff.close();
++++++++++++return+outStringBuf.toString();
++++++++}+catch+(IOException+e)+{
++++++++++++return+null;
++++++++}
++++}

++++public+static+boolean+appendFileValue(String+fileName,+String+value,
++++++++++++Context+context)+{
++++++++return+writeToFile(fileName,+value,+context,+Context.MODE_APPEND);
++++}

++++public+static+boolean+setFileValue(String+fileName,+String+value,
++++++++++++Context+context)+{
++++++++return+writeToFile(fileName,+value,+context,
++++++++++++++++Context.MODE_WORLD_READABLE);
++++}

++++public+static+boolean+writeToFile(String+fileName,+String+value,
++++++++++++Context+context,+int+writeOrAppendMode)+{
++++++++//+just+make+sure+it's+one+of+the+modes+we+support
++++++++if+(writeOrAppendMode+!=+Context.MODE_WORLD_READABLE
++++++++++++++++&&+writeOrAppendMode+!=+Context.MODE_WORLD_WRITEABLE
++++++++++++++++&&+writeOrAppendMode+!=+Context.MODE_APPEND)+{
++++++++++++return+false;
++++++++}
++++++++try+{
++++++++++++/*
+++++++++++++*+We+have+to+use+the+openFileOutput()-method+the+ActivityContext
+++++++++++++*+provides,+to+protect+your+file+from+others+and+This+is+done+for
+++++++++++++*+security-reasons.+We+chose+MODE_WORLD_READABLE,+because+we+have
+++++++++++++*+nothing+to+hide+in+our+file
+++++++++++++*/
++++++++++++FileOutputStream+fOut+=+context.openFileOutput(fileName,
++++++++++++++++++++writeOrAppendMode);
++++++++++++OutputStreamWriter+osw+=+new+OutputStreamWriter(fOut);
++++++++++++//+Write+the+string+to+the+file
++++++++++++osw.write(value);
++++++++++++//+save+and+close
++++++++++++osw.flush();
++++++++++++osw.close();
++++++++}+catch+(IOException+e)+{
++++++++++++return+false;
++++++++}
++++++++return+true;
++++}

++++public+static+void+deleteFile(String+fileName,+Context+context)+{
++++++++context.deleteFile(fileName);
++++}
}|code-block|syntax|javascript|1484730|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I decided to write a class from this thread that may be helpful to others. Note that this is currently intended to write in the "files" directory only (e.g. does not write to "sdcard" paths).

<pre><code>import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import android.content.Context;

public class AndroidFileFunctions {

 public static String getFileValue(String fileName, Context context) {
 try {
 StringBuffer outStringBuf = new StringBuffer();
 String inputLine = "";
 /*
 * We have to use the openFileInput()-method the ActivityContext
 * provides. Again for security reasons with openFileInput(...)
 */
 FileInputStream fIn = context.openFileInput(fileName);
 InputStreamReader isr = new InputStreamReader(fIn);
 BufferedReader inBuff = new BufferedReader(isr);
 while ((inputLine = inBuff.readLine()) != null) {
 outStringBuf.append(inputLine);
 outStringBuf.append("\n");
 }
 inBuff.close();
 return outStringBuf.toString();
 } catch (IOException e) {
 return null;
 }
 }

 public static boolean appendFileValue(String fileName, String value,
 Context context) {
 return writeToFile(fileName, value, context, Context.MODE_APPEND);
 }

 public static boolean setFileValue(String fileName, String value,
 Context context) {
 return writeToFile(fileName, value, context,
 Context.MODE_WORLD_READABLE);
 }

 public static boolean writeToFile(String fileName, String value,
 Context context, int writeOrAppendMode) {
 // just make sure it's one of the modes we support
 if (writeOrAppendMode != Context.MODE_WORLD_READABLE
 &amp;&amp; writeOrAppendMode != Context.MODE_WORLD_WRITEABLE
 &amp;&amp; writeOrAppendMode != Context.MODE_APPEND) {
 return false;
 }
 try {
 /*
 * We have to use the openFileOutput()-method the ActivityContext
 * provides, to protect your file from others and This is done for
 * security-reasons. We chose MODE_WORLD_READABLE, because we have
 * nothing to hide in our file
 */
 FileOutputStream fOut = context.openFileOutput(fileName,
 writeOrAppendMode);
 OutputStreamWriter osw = new OutputStreamWriter(fOut);
 // Write the string to the file
 osw.write(value);
 // save and close
 osw.flush();
 osw.close();
 } catch (IOException e) {
 return false;
 }
 return true;
 }

 public static void deleteFile(String fileName, Context context) {
 context.deleteFile(fileName);
 }
}
</code></pre>

blocks|key|1484807|text|写入文件test.txt：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1484808|String+filepath+="/mnt/sdcard/test.txt";
FileOutputStream+fos+=+null;
try+{
++++++++fos+=+new+FileOutputStream(filepath);
++++++++byte[]+buffer+=+"This+will+be+writtent+in+test.txt".getBytes();
++++++++fos.write(buffer,+0,+buffer.length);
++++++++fos.close();
++++}+catch+(FileNotFoundException+e)+{
+++++++++e.printStackTrace();
++++}+catch+(IOException+e)+{
+++++++++e.printStackTrace();
++++}finally{
++++++++if(fos+!=+null)
++++++++++++fos.close();
++++}|code-block|syntax|javascript|1484809|从文件test.txt读取：|1484810|String+filepath+="/mnt/sdcard/test.txt";++++++++
FileInputStream+fis+=+null;
try+{
+++++++fis+=+new+FileInputStream(filepath);
+++++++int+length+=+(int)+new+File(filepath).length();
+++++++byte[]+buffer+=+new+byte[length];
+++++++fis.read(buffer,+0,+length);
+++++++fis.close();
++++}+catch+(FileNotFoundException+e)+{
+++++++++e.printStackTrace();
++++}+catch+(IOException+e)+{
+++++++++e.printStackTrace();
++++}finally{
++++++++if(fis+!=+null)
++++++++++++fis.close();
+++}|1484811|注意:不要忘记在AndroidManifest.xml中添加这两个权限|1484812|<uses-permission+android:name="android.permission.WRITE_EXTERNAL_STORAGE"+/>
<uses-permission+android:name="android.permission.READ_EXTERNAL_STORAGE"+/>|1484813|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Write to a file test.txt:

<pre><code>String filepath ="/mnt/sdcard/test.txt";
FileOutputStream fos = null;
try {
 fos = new FileOutputStream(filepath);
 byte[] buffer = "This will be writtent in test.txt".getBytes();
 fos.write(buffer, 0, buffer.length);
 fos.close();
 } catch (FileNotFoundException e) {
 e.printStackTrace();
 } catch (IOException e) {
 e.printStackTrace();
 }finally{
 if(fos != null)
 fos.close();
 }
</code></pre>

Read from file test.txt:

<pre><code>String filepath ="/mnt/sdcard/test.txt"; 
FileInputStream fis = null;
try {
 fis = new FileInputStream(filepath);
 int length = (int) new File(filepath).length();
 byte[] buffer = new byte[length];
 fis.read(buffer, 0, length);
 fis.close();
 } catch (FileNotFoundException e) {
 e.printStackTrace();
 } catch (IOException e) {
 e.printStackTrace();
 }finally{
 if(fis != null)
 fis.close();
 }
</code></pre>

Note: don't forget to add these two permission in AndroidManifest.xml

<pre><code>&lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;
&lt;uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /&gt;
</code></pre>

How to create a file, write data into it and read data from it on Android? If possible provide a code snippet.

How to create a file in Android?

Android

如何在Android上创建文件、向其中写入数据以及从中读取数据？如果可能，请提供代码片段。

问如何在Android中创建文件？
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