Develop Reference

How to check files size

I have a problem getting the size of a file.
I have the following code:
File file = new File(path);
FilenameFilter mediafilefilter = new FilenameFilter(){
private String[] filter = {".txt"};
#Override
public boolean accept(File dir, String filename) {
for(int i= 0;i< filter.length ; i++){
if(filename.indexOf(filter[i]) != -1)return true;
}
return false;
}
};
File[] flies = file.listFiles(mediafilefilter);
if (files != null) {
{
if (files.length > 0)
{
System.out.println("Totol is :" + files.length);
for (int j = 0; j < files.length; j++) //not work
}
}
}
some text file is 0 byte

Like that
list[0].length()/1024
list[0] is the first file in your array

public long getFileSizes(File f) throws Exception{
long s=0;
if (f.exists()) {
FileInputStream fis = null;
fis = new FileInputStream(f);
s= fis.available();
}
return s;
}

get images' names in directory

How can I get only images' names in known directory.
Trying use this (from here)
File sdCardRoot = Environment.getExternalStorageDirectory();
File yourDir = new File(sdCardRoot, "yourpath");
for (File f : yourDir.listFiles()) {
if (f.isFile())
String name = f.getName();
// make something with the name
}
but don't works.
How can I do this?

private ArrayList<File> fileList = new ArrayList<File>();
//getting SDcard root path
File root = new File(Environment.getExternalStorageDirectory()
.getAbsolutePath());
getfile(root);
for (int i = 0; i < fileList.size(); i++) {
// getting file name
System.out.println(fileList.get(i).getName());
if (fileList.get(i).isDirectory()) {
                teSystem.out.println("This is Directory not an image");
            }
}
// getfile(file) method
public ArrayList<File> getfile(File dir) {
File listFile[] = dir.listFiles();
if (listFile != null && listFile.length > 0) {
for (int i = 0; i < listFile.length; i++) {
if (listFile[i].isDirectory()) {
fileList.add(listFile[i]);
getfile(listFile[i]);
} else {
if (listFile[i].getName().endsWith(".png")
|| listFile[i].getName().endsWith(".jpg")
|| listFile[i].getName().endsWith(".jpeg")
|| listFile[i].getName().endsWith(".gif"))
{
fileList.add(listFile[i]);
}
}
}
}
return fileList;
}
hope it will help your purpose.

Delete only .jpg files from folder in android

This is any way to delete only .jpg files from folder?
This is my remove method:
if (dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
new File(dir, children[i]).delete();
}
}
How can I remove only .jpg files from folder?

if (dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
String filename = children[i];
if (filename.endsWith(".jpeg") || filename.endsWith(".jpg"))
new File(dir, filename).delete();
}
}
or you prefer the for-each version
if (dir.isDirectory()) {
String[] children = dir.list();
for (String child : children) {
if (child.endsWith(".jpeg") || child.endsWith(".jpeg"))
new File(dir, child).delete();
}
}

Try like this
if (dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
if(children[i].endsWith('.jpg' || children[i].endsWith('.jpeg'))
{
new File(dir, children[i]).delete();
}
}
}

File dir = new File(android.os.Environment.getExternalStorageDirectory(),"MyFolder");
Then call
walkdir(dir);
public void walkdir(File dir) {
String Patternjpg = ".jpg";
File listFile[] = dir.listFiles();
if (listFile != null) {
for (int i = 0; i < listFile.length; i++) {
if (listFile[i].isDirectory()) {
walkdir(listFile[i]);
} else {
if (listFile[i].getName().endsWith(Patternjpg)){
//Do what ever u want
listFile[i].delete();
}
}
}
}
}

Filtering files in a directory on Android

In my app i am getting the images from a folder in gallery and saving it into an array list.Now i want to extract only the files with .jpg extension.How can i do it
The code for saving to array list is
private List<String> ReadSDCard()
{
//It have to be matched with the directory in SDCard
File f = new File("sdcard/data/crak");
File[] files=f.listFiles();
for(int i=0; i<files.length; i++)
{
File file = files[i];
/*It's assumed that all file in the path are in supported type*/
tFileList.add(file.getPath());
}
return tFileList;
}

You can use FilenameFilter interface to Filter the Files.
Change your codeline
File[] files=f.listFiles();
as below:
File[] jpgfiles = f.listFiles(new FileFilter() {
#Override
public boolean accept(File file)
{
return (file.getPath().endsWith(".jpg")||file.getPath().endsWith(".jpeg"));
}
});

Use .endsWith() method from Java String Class to check File Extension from file path.
Method:
public boolean endsWith(String suffix)
Your Code something like,
private List<String> ReadSDCard()
{
//It have to be matched with the directory in SDCard
File f = new File("sdcard/data/crak");
File[] files=f.listFiles();
for(int i=0; i<files.length; i++)
{
File file = files[i];
/*It's assumed that all file in the path are in supported type*/
String filePath = file.getPath();
if(filePath.endsWith(".jpg")) // Condition to check .jpg file extension
tFileList.add(filePath);
}
return tFileList;
}

private List<String> ReadSDCard()
{
String extension = "";
File f = new File("sdcard/data/crak");
File[] files=f.listFiles();
for(int i=0; i<files.length; i++)
{
File file = files[i];
int ind = files[i].getPath().lastIndexOf('.');
if (ind > 0) {
extension = files[i].getPath().substring(i+1);// this is the extension
if(extension.equals("jpg"))
{
tFileList.add(file.getPath());
}
}
}
return tFileList;
}

In your code add the following:
String filePath = file.getPath();
if(filePath.endsWith(".jpg"))
tFileList.add(filePath);

Accessing Android DCIM Images

How does one obtain images from the /DCIM/100ANDRO folder?
I have tried
File rootsd = Environment.getExternalStorageDirectory();
File dcim = new File(rootsd.getAbsolutePath() + "/DCIM/100ANDRO");
File[] imagelist = dcim.listFiles(new FilenameFilter(){
public boolean accept(File dir, String name)
{
return ((name.endsWith(".jpg"))||(name.endsWith(".png")));
}
});
mFiles = new String[imagelist.length];
for(int i= 0 ; i< imagelist.length; i++)
{
mFiles[i] = imagelist[i].getAbsolutePath();
}
mUrls = new Uri[mFiles.length];
for(int i=0; i < mFiles.length; i++)
{
mUrls[i] = Uri.parse(mFiles[i]);
}
but I got a Null Pointer Exception.

Have you remembered to give the app permission to write the external memory?
It is done in the AndroidManifest.xml file, by adding
"android.permission.WRITE_EXTERNAL_STORAGE"
Since you are making a new file object, this is needed, I would guess.