android image exif阅读器第三方api

Question

是否有任何第三方api for android从图像中读取exif标签,支持从1.5开始的api级别.

Answer 1

Drew Noakes 的元数据提取库适用于在早期Android平台版本上提取EXIF标签,只需略微修改即可.我在Android 1.6上使用它来从JPEG图像中提取标签.

注意:较新版本的元数据提取器可直接在Android上运行而无需修改.

您需要自己下载并构建源代码,并将其与您的应用程序打包在一起.(我正在使用版本2.3.1.)进行以下更改com.drew.imaging.jpeg.JpegMetadataReader:

• 删除以下import语句:

  import com.sun.image.codec.jpeg.JPEGDecodeParam;

• 删除以下方法(Android上不需要):

  public static Metadata readMetadata(JPEGDecodeParam decodeParam) { ... }

删除com.drew.metadata.SampleUsage引用上面删除的方法的类.同时删除所有测试包.

这里的所有都是它的.以下是使用JpegMetadataReader从存储在SD卡上的JPEG图像中提取日期时间标记的示例:

import com.drew.imaging.jpeg.JpegMetadataReader;
import com.drew.metadata.Directory;
import com.drew.metadata.Metadata;
import com.drew.metadata.exif.ExifDirectory;

// other imports and class definition removed for brevity

public static Date extractExifDateTime(String imagePath)
{
    Log.d("exif", "Attempting to extract EXIF date/time from image at " + imagePath);
    Date datetime = new Date(0); // or initialize to null, if you prefer
    try
    {
        Metadata metadata = JpegMetadataReader.readMetadata(new File(imagePath));
        Directory exifDirectory = metadata.getDirectory(ExifDirectory.class);

        // these are listed in order of preference
        int[] datetimeTags = new int[] { ExifDirectory.TAG_DATETIME_ORIGINAL,
                                         ExifDirectory.TAG_DATETIME,
                                         ExifDirectory.TAG_DATETIME_DIGITIZED };
        int datetimeTag = -1;
        for (int tag : datetimeTags)
        {
            if (exifDirectory.containsTag(tag))
            {
                datetimeTag = tag;
                break;
            }
        }

        if (datetimeTag != -1)
        {
            Log.d("exif", "Using tag " + exifDirectory.getTagName(datetimeTag) + " for timestamp");

            SimpleDateFormat exifDatetimeFormat = new SimpleDateFormat("yyyy:MM:dd HH:mm:ss");
            datetime = exifDatetimeFormat.parse(exifDirectory.getString(datetimeTag));
        }
        else
        {
            Log.d("exif", "No date/time tags were found");
        }
    }
    catch (Exception e)
    {
        Log.w("exif", "Unable to extract EXIF metadata from image at " + imagePath, e);
    }
    return datetime;
}