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
检测任何文件的mime类型
public String getMimeType(Uri uri) {
String mimeType = null;
if (ContentResolver.SCHEME_CONTENT.equals(uri.getScheme())) {
ContentResolver cr = getAppContext().getContentResolver();
mimeType = cr.getType(uri);
} else {
String fileExtension = MimeTypeMap.getFileExtensionFromUrl(uri
.toString());
mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(
fileExtension.toLowerCase());
}
return mimeType;
}
其他回答
首先，你应该考虑调用MimeTypeMap#getMimeTypeFromExtension()，就像这样:
// url = file path or whatever suitable URL you want.
public static String getMimeType(String url) {
String type = null;
String extension = MimeTypeMap.getFileExtensionFromUrl(url);
if (extension != null) {
type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
}
return type;
}
对于Xamarin Android(来自@HoaLe的回答)
public String getMimeType(Uri uri) {
String mimeType = null;
if (uri.Scheme.Equals(ContentResolver.SchemeContent))
{
ContentResolver cr = Application.Context.ContentResolver;
mimeType = cr.GetType(uri);
}
else
{
String fileExtension = MimeTypeMap.GetFileExtensionFromUrl(uri.ToString());
mimeType = MimeTypeMap.Singleton.GetMimeTypeFromExtension(
fileExtension.ToLower());
}
return mimeType;
}
// This will return the mimeType.
// for eg. xyz.png it will return image/png.
// here uri is the file that we were picked using intent from ext/internal storage.
private String getMimeType(Uri uri) {
// This class provides applications access to the content model.
ContentResolver contentResolver = getContentResolver();
// getType(Uri url)-Return the MIME type of the given content URL.
return contentResolver.getType(uri);
}
而从资产/文件(注意，在MimeTypeMap中缺少一些情况)。
private String getMimeType(String path) {
if (null == path) return "*/*";
String extension = path;
int lastDot = extension.lastIndexOf('.');
if (lastDot != -1) {
extension = extension.substring(lastDot + 1);
}
// Convert the URI string to lower case to ensure compatibility with MimeTypeMap (see CB-2185).
extension = extension.toLowerCase(Locale.getDefault());
if (extension.equals("3ga")) {
return "audio/3gpp";
} else if (extension.equals("js")) {
return "text/javascript";
} else if (extension.equals("woff")) {
return "application/x-font-woff";
} else {
// TODO
// anyting missing from the map (http://www.sitepoint.com/web-foundations/mime-types-complete-list/)
// reference: http://grepcode.com/file/repo1.maven.org/maven2/com.google.okhttp/okhttp/20120626/libcore/net/MimeUtils.java#MimeUtils
}
return MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
}
而使用ContentResolver
contentResolver.getType(uri)
当http/https请求
try {
HttpURLConnection conn = httpClient.open(new URL(uri.toString()));
conn.setDoInput(false);
conn.setRequestMethod("HEAD");
return conn.getHeaderField("Content-Type");
} catch (IOException e) {
}
以下是我在我的Android应用程序中使用的解决方案:
public static String getMimeType(String url)
{
String extension = url.substring(url.lastIndexOf("."));
String mimeTypeMap = MimeTypeMap.getFileExtensionFromUrl(extension);
String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(mimeTypeMap);
return mimeType;
}
