Several ways to read the contents of a file on Android by line _android

First, simple version

Copy Code code as follows:

Import Java.io.FileInputStream;
void Readfileonline () {
String strFileName = "Filename.txt";
FileInputStream FIS = openfileinput (strFileName);
StringBuffer sbuffer = new StringBuffer ();
DataInputStream Dataio = new DataInputStream (FIS);
String strLine = null;
while ((StrLine = Dataio.readline ())!= null) {
Sbuffer.append (strLine + "\ n");
}
Dataio.close ();
Fis.close ();
}

Second, concise version

Copy Code code as follows:

Reading content in a text file
public static string Readtxtfile (String strFilePath)
{
String path = strFilePath;
String content = ""; File content string
Open File
File File = new file (path);
If path is an argument passed over, you can make a non-directory judgment
if (File.isdirectory ())
{
LOG.D ("Testfile", "the File doesn ' t not exist.");
}
Else
{
try {
InputStream instream = new FileInputStream (file);
if (instream!= null)
{
InputStreamReader Inputreader = new InputStreamReader (instream);
BufferedReader buffreader = new BufferedReader (Inputreader);
String Line;
Branch Read
while (line = Buffreader.readline ())!= null) {
Content + = line + "\ n";
}
Instream.close ();
}
}
catch (Java.io.FileNotFoundException e)
{
LOG.D ("Testfile", "the File doesn ' t not exist.");
}
catch (IOException E)
{
LOG.D ("Testfile", E.getmessage ());
}
}
return content;
}

Third, apk for long time use, and regular data

1, read the contents of the file line by row

Copy Code code as follows:

First, define a data type to hold the contents of the Read file
Class Weightrecord {
String timestamp;
float weight;
Public Weightrecord (String timestamp, float weight) {
This.timestamp = timestamp;
This.weight = weight;

}
}

Start reading
Private weightrecord[] Readlog () throws Exception {
arraylist<weightrecord> result = new arraylist<weightrecord> ();
File root = Environment.getexternalstoragedirectory ();
if (root = null)
throw new Exception ("External storage dir not found");
First find the file
File Weightlogfile = new file (Root,weightservice.logfilepath);
if (!weightlogfile.exists ())
throw new Exception ("LogFile" "+weightlogfile+" ' not Found ');
if (!weightlogfile.canread ())
throw new Exception ("LogFile" "+weightlogfile+" ' not readable ');
Long modtime = weightlogfile.lastmodified ();
if (modtime = = lastrecordfilemodtime)
return lastlog;
File exists, is readable, and is recently modified--reread it.
Lastrecordfilemodtime = Modtime;
Then convert the file into a byte stream read
FileReader reader = new FileReader (weightlogfile);
BufferedReader in = new BufferedReader (reader);
Long currenttime =-1;
Read-by-line
String line = In.readline ();
while (line!= null) {
Weightrecord rec = parseline (line);
if (rec = null)
LOG.E (TAG, "Could not parse line: '" +line+ "");
else if (Long.parselong (Rec.timestamp) < currenttime)
LOG.E (TAG, "ignoring '" +line+ "' since it ' older than log Line");
else {
LOG.I (TAG, "line=" +rec);
Result.add (REC);
CurrentTime = Long.parselong (Rec.timestamp);
}
line = In.readline ();
}
In.close ();
Lastlog = (weightrecord[]) Result.toarray (new Weightrecord[result.size ()));
return lastlog;
}
Parse each row
Private Weightrecord ParseLine (String line) {
if (line = = null)
return null;
string[] split = Line.split ("[;]");
if (Split.length < 2)
return null;
if (Split[0].equals ("Date"))
return null;
try {
String timestamp = (split[0]);
float weight = float.parsefloat (split[1]);
return new Weightrecord (timestamp,weight);
}
catch (Exception e) {
LOG.E (TAG, "Invalid format in line" "+line+");
return null;
}
}

2, Save as file

Copy Code code as follows:

public boolean logweight (Intent batterychangeintent) {
LOG.I (TAG, "logbattery");
if (batterychangeintent = null)
return false;
try {
FileWriter out = null;
if (mweightlogfile!= null) {
try {
out = new FileWriter (Mweightlogfile, true);
}
catch (Exception e) {}
}
if (out = = null) {
File root = Environment.getexternalstoragedirectory ();
if (root = null)
throw new Exception ("External storage dir not found");
Mweightlogfile = new File (Root,weightservice.logfilepath);
Boolean fileexists = Mweightlogfile.exists ();
if (!fileexists) {
if (!mweightlogfile.getparentfile (). Mkdirs ()) {
Toast.maketext (This, "Create file Failed", Toast.length_short). Show ();
}
Mweightlogfile.createnewfile ();
}
if (!mweightlogfile.exists ()) {
LOG.I (TAG, "out = null");
throw new Exception ("Creation of File" +mweightlogfile.tostring () + "' failed");
}
if (!mweightlogfile.canwrite ())
throw new Exception ("File" +mweightlogfile.tostring () + "' is not writable ');
out = new FileWriter (Mweightlogfile, true);
if (!fileexists) {
String Header = Createheadline ();
Out.write (header);
Out.write (' \ n ');
}
}
LOG.I (TAG, "Out!= null");
String Extras = Createbatteryinfoline (batterychangeintent);
Out.write (extras);
Out.write (' \ n ');
Out.flush ();
Out.close ();
return true;
catch (Exception e) {
LOG.E (Tag,e.getmessage (), E);
return false;
}
}