是否有任何其他替代方法可以获取 ImageView 并将其转换为位图以在 android 中进行图像分类？答案

【问题标题】：Is there any other alternative available to get ImageView and convert it into Bitmap for image classification in android?是否有任何其他替代方法可以获取 ImageView 并将其转换为位图以在 android 中进行图像分类？
【发布时间】：2019-04-10 04:36:40
【问题描述】：

我想从ImageView 获取位图。我使用了以下代码，但它抛出了ArrayIndexOutOfBoundExcpetion。如何解决？

 bitmap.getPixels(mImagePixels, 0, bitmap.getWidth(), 0, 0,
                    bitmap.getWidth(), bitmap.getHeight());

            int pixel = 0;
            for (int i = 0; i < DIM_IMG_SIZE_WIDTH; ++i) {
                for (int j = 0; j < DIM_IMG_SIZE_HEIGHT; ++j) {
                    final int val = mImagePixels[pixel++];
                    mImgData.putFloat(convertToGreyScale(val));
                }
            }

        }
        private float convertToGreyScale(int color) {
            return (((color >> 16) & 0xFF) + ((color >> 8) & 0xFF) + (color & 0xFF)) / 3.0f / 255.0f;
        }

     java.lang.ArrayIndexOutOfBoundsException
            at android.graphics.Bitmap.checkPixelsAccess(Bitmap.java:1824)
            at android.graphics.Bitmap.getPixels(Bitmap.java:1765)
            at com.drprajapati.android.plantclassification.ml.Classifier.convertBitmapToByteBuffer(Classifier.java:69)
            at com.drprajapati.android.plantclassification.ml.Classifier.classify(Classifier.java:53)
            at com.drprajapati.android.plantclassification.MainActivity$1.onClick(MainActivity.java:58)
            at android.view.View.performClick(View.java:6671)
            at android.view.View.performClickInternal(View.java:6640)
            at android.view.View.access$3100(View.java:791)
            at android.view.View$PerformClick.run(View.java:26173)
            at android.os.Handler.handleCallback(Handler.java:873)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:193)
            at android.app.ActivityThread.main(ActivityThread.java:6912)
            at java.lang.reflect.Method.invoke(Native Method)
            at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:537)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

【问题讨论】：

如果您觉得方便，可以使用BitmapFactory (developer.android.com/reference/android/graphics/BitmapFactory)

标签： android machine-learning tensorflow-lite

【解决方案1】：

考虑试试这个

BitmapDrawable drawable = (BitmapDrawable) imageView.getDrawable();
Bitmap bitmap = drawable.getBitmap();

【讨论】：

【解决方案2】：

您可以从ImageView中以drawable的形式获取图像，然后通过将drawable传递给以下方法将drawable转换为位图。

public static Bitmap drawableToBitmap (Drawable drawable) {
Bitmap bitmap = null;

if (drawable instanceof BitmapDrawable) {
    BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
    if(bitmapDrawable.getBitmap() != null) {
        return bitmapDrawable.getBitmap();
    }
}

if(drawable.getIntrinsicWidth() <= 0 || drawable.getIntrinsicHeight() <= 0) {
    bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); // Single color 
bitmap will be created of 1x1 pixel
} else {
    bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), 
drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
}

Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}

【讨论】：