Data Storage - Text aus Datei auslesen

Du musst schon aktiv aus der Datei lesen, ja und ein Java Buch das einem die Basics vermittelt ist ebenso wichtig wie munter drauf rumprobieren!



hth,
Mac

Ich hab mir mal diese nützliche klasse geschrieben:

[code]
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Environment;
import android.util.Log;


public class ExternalStorageManager {

private File externalStorage;

private boolean isExternalStorageAvailable = false;
private boolean isExternalStorageWriteable = false;


public ExternalStorageManager() {
externalStorage = Environment.getExternalStorageDirectory();
checkExternalStorageAvailability();
}

public boolean canRead(){
return isExternalStorageAvailable;
}

public boolean canWrite(){
return isExternalStorageWriteable;
}

public boolean exist(String path){
return (canRead() && (new File(externalStorage, path).exists()));
}

public void makeDir(String path){
if(canWrite()){
File make = new File(externalStorage, path);
make.mkdirs();
}
}

public void makeDirIfNotExist(String path){
if(!exist(path)){
makeDir(path);
}
}

public void write(String path, String file, String text){
try {
if (externalStorage.canWrite()){
File tmpfile = new File(externalStorage, path+file);
FileWriter writer = new FileWriter(tmpfile);
BufferedWriter out = new BufferedWriter(writer);
out.write(text);
out.close();
}
} catch (IOException e) {
Log.e("ExternalStorageManager", "Could not write file " + e.getMessage());
}
}

public String[] read(String path, String filename){
try{
ArrayList<String> tmpList = new ArrayList<String>();
File f = new File(externalStorage, path+filename);
FileInputStream fileIS = new FileInputStream(f);
BufferedReader buf = new BufferedReader(new InputStreamReader(fileIS));

String l = "";
while((l = buf.readLine())!= null){
tmpList.add(l);
}
String [] r = new String[tmpList.size()];
for(int i = 0; i < tmpList.size(); i++){
r[i] = tmpList.get(i);
}
return r;

} catch (FileNotFoundException e) {
Log.e("ExternalStorageManager", "Cant find file " + externalStorage + path + filename);
} catch (IOException e){
Log.e("ExternalStorageManager", "IOException while reading " + externalStorage + path + filename);
}
return null;

}

public String[] readDirectory(String path){
File dir = new File(externalStorage, path);
return dir.list();
}

public File[] getFileList(String path){
String[] names = readDirectory(path);
File[] files = new File[names.length];
for (int i = 0; i < names.length; i++) {
files[i] = new File(externalStorage, path+names[i]);
}
return files;
}

public void deleteFile(String path){
new File(externalStorage,path).delete();
}

private void checkExternalStorageAvailability(){

String state = Environment.getExternalStorageState();

if (Environment.MEDIA_MOUNTED.equals(state)) {
// We can read and write the media
isExternalStorageAvailable = isExternalStorageWriteable = true;
Log.i("ExternalStorageManager", "We can read and write the media");
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// We can only read the media
Log.i("ExternalStorageManager", "We can only read the media");
isExternalStorageAvailable = true;
isExternalStorageWriteable = false;
} else {
// Something else is wrong. It may be one of many other states, but all we need
// to know is we can neither read nor write
isExternalStorageAvailable = isExternalStorageWriteable = false;
}
}

}

[/code]

— geändert am 21.06.2010, 22:28:54