假设我有一个完整的文件路径:(/sdcard/tlogo.png)。我想知道它的mime类型。
我为它创建了一个函数
public static String getMimeType(File file, Context context)
{
Uri uri = Uri.fromFile(file);
ContentResolver cR = context.getContentResolver();
MimeTypeMap mime = MimeTypeMap.getSingleton();
String type = mime.getExtensionFromMimeType(cR.getType(uri));
return type;
}
但当我调用它时，它返回null。
File file = new File(filePath);
String fileType=CommonFunctions.getMimeType(file, context);
当前回答
// new processing the mime type out of Uri which may return null in some cases
String mimeType = getContentResolver().getType(uri);
// old processing the mime type out of path using the extension part if new way returned null
if (mimeType == null){mimeType URLConnection.guessContentTypeFromName(path);}
其他回答
我也遇到过类似的问题。到目前为止，我知道不同的名字可能会有不同的结果，所以最终得出了这个解决方案。
public String getMimeType(String filePath) {
String type = null;
String extension = null;
int i = filePath.lastIndexOf('.');
if (i > 0)
extension = filePath.substring(i+1);
if (extension != null)
type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
return type;
}
这里没有一个答案是完美的。以下是一个结合了所有热门答案的最佳元素的答案:
public final class FileUtil {
// By default, Android doesn't provide support for JSON
public static final String MIME_TYPE_JSON = "application/json";
@Nullable
public static String getMimeType(@NonNull Context context, @NonNull Uri uri) {
String mimeType = null;
if (uri.getScheme().equals(ContentResolver.SCHEME_CONTENT)) {
ContentResolver cr = context.getContentResolver();
mimeType = cr.getType(uri);
} else {
String fileExtension = getExtension(uri.toString());
if(fileExtension == null){
return null;
}
mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(
fileExtension.toLowerCase());
if(mimeType == null){
// Handle the misc file extensions
return handleMiscFileExtensions(fileExtension);
}
}
return mimeType;
}
@Nullable
private static String getExtension(@Nullable String fileName){
if(fileName == null || TextUtils.isEmpty(fileName)){
return null;
}
char[] arrayOfFilename = fileName.toCharArray();
for(int i = arrayOfFilename.length-1; i > 0; i--){
if(arrayOfFilename[i] == '.'){
return fileName.substring(i+1, fileName.length());
}
}
return null;
}
@Nullable
private static String handleMiscFileExtensions(@NonNull String extension){
if(extension.equals("json")){
return MIME_TYPE_JSON;
}
else{
return null;
}
}
}
Mime从本地文件:
String url = file.getAbsolutePath();
FileNameMap fileNameMap = URLConnection.getFileNameMap();
String mime = fileNameMap.getContentTypeFor("file://"+url);
上面的解决方案在.rar文件的情况下返回null，使用URLConnection.guessContentTypeFromName(url)在这种情况下工作。
Intent myIntent = new Intent(android.content.Intent.ACTION_VIEW);
File file = new File(filePatch);
Uri uris = Uri.fromFile(file);
String mimetype = null;
if
(uris.getScheme().equals(ContentResolver.SCHEME_CONTENT)) {
ContentResolver cr =
getApplicationContext().getContentResolver();
mimetype = cr.getType(uris);
} else {
String fileExtension =
MimeTypeMap.getFileExtensionFromUrl(uris.toString());
mimetype = MimeTypeMap.getSingleton().getMimeTypeFromExtension(fileExtension.toLowerCase());
}
