如何在Android中通过G4压缩将JPEG图像转换为TIFF格式？

Question

I am developing an android application and I want to be able to convert the camera pictures I take to tiff with Group 4 compression.

I tried using this Android-ImageMagick library , but I get the following error:

java.lang.UnsatisfiedLinkError - NDK

I referred to this StackOverflow question to solve but it didn't work.

Error occurs at the codes of library, Magick.java:43 line is the call of init(); method. Since we use of Gradle in Android Studio, I strongly doubt that it's because of Gradle. The explanation gave by the author of the library “how to use it” is based on project without Gradle. If we change the name of method “init()” to another name like “test()”, the error occurs at other native method. Our structure of project:
and have added “ndk.dir” into local.properties, tried to add “sourceSets":

{
        main {
            jni.srcDirs=['jniLibs']
        }
    }
    ” at build.gradle.

    /**
     * The sole purchase of this class is to cause the native
     * library to be loaded whenever a concrete class is used
     * and provide utility methods.
     *
     * @author Eric Yeo
     * @author Max Kollegov <virtual_max@geocities.com>
     */
    public class Magick {

        static {
            /*String clprop = System.getProperty("jmagick.systemclassloader");
            if (clprop == null || clprop.equalsIgnoreCase("yes")) {
                try {
                    ClassLoader.getSystemClassLoader()
                        .loadClass("magick.MagickLoader").newInstance();
                }
                catch(ClassN`enter code here`otFoundException e) {
                    throw new RuntimeException("Can't load MagickLoader " +
                                               "(class not found)");
                }
                catch(IllegalAccessException e) {
                    throw new RuntimeException("Access to SystemClassLoader "+
                                               "denied (IllegalAccessException)");
                }
                catch(InstantiationException e) {
                    throw new RuntimeException("Can't instantiate MagicLoader " +
                                               "(InstantiationException)");
                }
            }
            else {
                System.loadLibrary("JMagick");
            }*/

            System.loadLibrary("imagemagick");

            init();
        }


        /**
         * Initializes the ImageMagic system
         */
        private static native void init();


        /**
         * Parses a geometry specification and returns the
         * width, height, x, and y values in the rectangle.
         * It also returns flags that indicates which of the
         * four values (width, height, xoffset, yoffset) were
         * located in the string, and whether the x and y values
         * are negative.  In addition, there are flags to report
         * any meta characters (%, !, <, and >).
         * @param geometry String containing the geometry specifications
         * @param rect The rectangle of values x, y, width and height
         * @return bitmask indicating the values in the geometry string
         * @see magick.GeometryFlags
         */
        public static native int parseImageGeometry(String geometry, Rectangle rect);

    }

This is the error I get:

java.lang.UnsatisfiedLinkError: Native method not found: com.test.comp.magick.Magick.init:()V
            at com.test.comp.magick.Magick.init(Native Method)
            at com.test.comp.magick.Magick.<clinit>(Magick.java:43)
            at com.test.comp.magick.util.MagickBitmap.fromBitmap(MagickBitmap.java:41)
            at com.test.comp.activity.MainActivity.convertAndSendImage(MainActivity.java:60)
            at com.test.comp.activity.MainActivity.onActivityResult(MainActivity.java:84)
            at android.app.Activity.dispatchActivityResult(Activity.java:5423)
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3347)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3394)
            at android.app.ActivityThread.access$1300(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

UnsatisfiedLinkError are thrown if ImageMagick library is not installed into your apk and causing linkage error:

Your library must be in directory /project/libs/armeabi/