將createBitmap從Java轉換為JNI

Question

我想在JNI使用此代碼，而無需回到Java 。

我已經將位圖操作轉換為JNI（由於使用了其他stackoverflow海報），但這似乎更加復雜，因為我不知道如何調用構造函數。

Bitmap bmp;
bmp = ((BitmapDrawable)imgview.getDrawable()).getBitmap();
if (bmp == null || !bmp.isMutable()) 
   Bitmap bmp = Bitmap.createBitmap(w, h, Config.ARGB_8888);

   // bitmap manipulations goes here
   jclass java_bitmap_class = (env)->GetObjectClass(java_bitmap);
   class SkBitmap;
   SkBitmap *sk_bitmap = (SkBitmap*)(env)->CallIntMethod(
      java_bitmap, (env)->GetMethodID(java_bitmap_class, "ni", "()I"));
    // there is more c++ code to manipulate bmp, but it is not relevant to a question

imgview.setImageBitmap(bmp);

Answer 1

好的，一旦您掌握了java-> jni的翻譯，它實際上非常簡單。 基本上，您可以在JNI方面做任何事情，而在Java中可以做。 是的，看起來很亂。 我決定不在JNI中創建位圖，而是訪問現有的位圖。

JNIEnv* Env = 0; jobject Obj; 
jclass cls = 0, ClassImageView = 0, class_drawable = 0, java_bitmap_class = 0;
jmethodID jcontrol_ui = 0, jfindViewById = 0, jgetBitmap = 0, jgetDrawable = 0;

int *getViewBitmapBuffer(int ID) {
  jobject image_view = (jobject) (Env)->CallObjectMethod(Obj, jfindViewById, ID);
  // some values can be cached, hence the checks for "(something == 0)"
  if (ClassImageView == 0) ClassImageView = (Env)->GetObjectClass(image_view);
  if (jgetDrawable == 0) jgetDrawable = (Env)->GetMethodID(ClassImageView, "getDrawable", sig_drawable);
  jobject drawable = (jobject) (Env)->CallObjectMethod(image_view, jgetDrawable);
  if (class_drawable == 0) class_drawable = (Env)->GetObjectClass(drawable);
  if (jgetBitmap == 0) jgetBitmap = (Env)->GetMethodID(class_drawable, "getBitmap", sig_bitmap);
  jobject java_bitmap = (jobject) (Env)->CallObjectMethod(drawable, jgetBitmap);
  if (java_bitmap_class == 0) java_bitmap_class = (Env)->GetObjectClass(java_bitmap);
  class SkBitmap;
  SkBitmap *sk_bitmap = (SkBitmap*)(Env)->CallIntMethod(java_bitmap, (Env)->GetMethodID(java_bitmap_class, "ni", "()I"));
  SkPixelRef *sk_pix_ref;
  sk_pix_ref = (SkPixelRef*)((int*)sk_bitmap)[1];
  int *B = (int*) sk_pix_ref->GetPixels();
  return B;
}