Cannot open image file stored in sdcard

问题

In my application I save the contents of a tableLayout as an image in a folder. To allow user to open a file from the saved images I've created a text file that contains the names of these files. These file names will be loaded in an array (files) later. User clicks on "open" to see a list of file names and selects the one he wants to open. I'm using the following code to open a file.

final String imageInSD = extStorageDirectory+"/myFolder/"+files[which];
//where 'files' is an array of strings and contains the names of files.
//and 'which' is the index of the selected element in the list  
Bitmap bitmap = BitmapFactory.decodeFile(imageInSD);  
ImageView ivv=(ImageView) findViewById(R.id.imageView);
ivv.setImageBitmap(bitmap);

when I try it nothing happens so I tried the following

final String imageInSD = extStorageDirectory+"/myFolder/myFile.PNG";
Bitmap bitmap = BitmapFactory.decodeFile(imageInSD);  
ImageView ivv=(ImageView) findViewById(R.id.imageView);
ivv.setImageBitmap(bitmap);

And it shows the image named myFile. I've already checked if I'm getting the correct file name and path and it seems to be correct. (when i click on myFile.PNG in the list and show the path I get "/mnt/sdcard/myFolder/myFile.PNG").

Why doesn't it work when I use the first code?

回答1:

String concatenation isn't a good way to combine paths. It is better to use the File constructor :

File directory = new File(extStorageDirectory, "myFolder");
File fileInDirectory = new File(directory, files[which]);
Bitmap bitmap = BitmapFactory.decodeFile(fileInDirectory.getAbsolutePath());

来源：https://stackoverflow.com/questions/8563365/cannot-open-image-file-stored-in-sdcard