FileNotFoundException：/storage/emulated/0/JsonParseTutorialCache：打开失败：ENOENT（没有这样的文件或目录）

Question

I'm using GridView to load json data holding images. When I built project it happened some exceptions

AndroidManifest.xml:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

FileCache class:

public class FileCache {

private File cacheDir;

public FileCache(Context context) {
    // Find the dir to save cached images
    if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_MOUNTED))
        cacheDir = new File(
                android.os.Environment.getExternalStorageDirectory(),
                "JsonParseTutorialCache");
    else
        cacheDir = context.getCacheDir();
    if (!cacheDir.exists())
        cacheDir.mkdirs();
}

public File getFile(String url) throws IOException {
    String filename = String.valueOf(url.hashCode());
    // String filename = URLEncoder.encode(url);
    File f = new File(cacheDir, filename);
    f.createNewFile();
    return f;
}

public void clear() {
    File[] files = cacheDir.listFiles();
    if (files == null)
        return;
    for (File f : files)
        f.delete();
 }

}

Logcat:

W/System.err: java.io.IOException: open failed: ENOENT (No such file or directory)
W/System.err:     at java.io.File.createNewFile(File.java:939)
W/System.err:     at    com.totoroads.android.app.FileCache.getFile(FileCache.java:33) 
W/System.err:     at com.totoroads.android.app.ImageLoader.getBitmap(ImageLoader.java:64)
W/System.err:     at com.totoroads.android.app.ImageLoader.access$000(ImageLoader.java:29)
W/System.err:     at com.totoroads.android.app.ImageLoader$PhotosLoader.run(ImageLoader.java:155)
W/System.err:     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:423)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
W/System.err:     at java.lang.Thread.run(Thread.java:818)
W/System.err: Caused by: android.system.ErrnoException: open failed: ENOENT (No such file or directory)
W/System.err:     at libcore.io.Posix.open(Native Method)
W/System.err:     at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)
W/System.err:     at java.io.File.createNewFile(File.java:932)
W/System.err:   ... 9 more

I want to download, read and display images on GridView, How to fix those exceptions?

Answer 1

In my case, it was:

If targeting Android 10 (API level 29) or higher, set the value of requestLegacyExternalStorage to true in your app's AndroidManifest file.

<manifest ... >
<application android:requestLegacyExternalStorage="true" ... >

Answer 2

The code in FileCache.java is

public File getFile(String url) {
    String filename = String.valueOf(url.hashCode());
    // String filename = URLEncoder.encode(url);
    File f = new File(cacheDir, filename);
    return f;
}

A new file object has been created, but the file may not exist. So, replace the above code with

public File getFile(String url) {
    String filename = String.valueOf(url.hashCode());
    // String filename = URLEncoder.encode(url);
    File f = new File(cacheDir, filename);
    f.createNewFile();
    return f;
}

Hope, it helps.

Edit : As you're running your code on >= Android 6.0, you gotta request for permission to access External Storage at runtime. Adding those in AndroidManifest.xml isn't enough. You can use this link on how to do it.

Answer 3

You can use Picasso library for showing images in grid view. it is provide one line code for load image. Use Library function for load images--

Picasso.with(context).load(" YOURIMAGE ").into(imageView);

You can also resize images according to your requirement. and it is also manage internally cache mechanism

Refer Link for more info - http://square.github.io/picasso/

Answer 4

You can also save yourself the f.createNewFile and use File.createTempFile(imageFileName, ".jpg", storageDir)

So your method now becomes

public File getFile(String url) {
    String filename = String.valueOf(url.hashCode());
    // String filename = URLEncoder.encode(url);

    return File.createTempFile(filename, ".jpg", cacheDir);
}