OpenCVAndroid开发（一）app测试

先上效果图:

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主要是卡在调用手机相册图片,因为手机是Android9系统,访问相册需要申请权限.另外,图片的处理还是挺头疼的.

这是测试OpenCV环境是否搭好的测试app,虽然只是测试,尽量做到尽善尽美.
整个界面很简单:
xml文件:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="16dp"
    android:paddingBottom="16dp"
    tools:context=".ProcessImageActivity">

    <LinearLayout
        android:id="@+id/btn_group"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:orientation="horizontal">

        <Button
            android:id="@+id/select_btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/img"
            android:layout_weight="1"
            android:text="选择图片" />"

        <Button
            android:id="@+id/gray_btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/img"
            android:layout_weight="1"
            android:text="灰度化" />"
    </LinearLayout>
    <ImageView
        android:id="@+id/img"
        android:layout_below="@+id/btn_group"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true"
        android:src="@drawable/tayler"/>


</RelativeLayout>

调用相册图片

首先在android9.0的机子上,肯定是要进行动态权限申请的.
整理一下动态申请权限的语句:
这是一块模板,可以在String permission[]中添加一些权限

private void requirePermission(){
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
        String permission = Manifest.permission.WRITE_EXTERNAL_STORAGE;
        if (ActivityCompat.checkSelfPermission(MainActivity.this, permission)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{permission},123);
        }
    }
}

访问相册

intent跳转,隐式跳转

Intent albumIntent = new Intent(Intent.ACTION_GET_CONTENT);
albumIntent.addCategory(Intent.CATEGORY_OPENABLE);           //调用相册
albumIntent.setType("image/jpeg");
startActivityForResult(albumIntent, REQUEST_CODE_IMAGE);

跳转到startActivity后,具体的操作设计到对图片的操作.
这里的操作很多,因为imageview提供的方法很多,
使用setImageBitmap(),会出现图片无法显示的结果,可能原因是图片质量太大.需要对图片进行处理.
这里用到的是imageUtil工具,就是将一些方法封装成类.

  if (requestCode == 2 && resultCode == RESULT_OK) {
        Uri mPath = data.getData();
        if(imageUtil == null){
            imageUtil = new ImageUtil(this);
        }
        String file = imageUtil.getPath(mPath);
        Bitmap bitmap = imageUtil.decodeImage(file);
        if (bitmap == null) {

            return;
        }
        Log.i(TAG, "width=" + bitmap.getWidth() + ",height=" + bitmap.getHeight());

        imageView.setImageBitmap(bitmap);
}

imageUtil类中的getPath()方法.

public String getPath(Uri uri) {
    if (DocumentsContract.isDocumentUri(context, uri)) {
        final String docId = DocumentsContract.getDocumentId(uri);
        final String[] split = docId.split(":");
        final String type = split[0];

        Uri contentUri = null;
        if ("image".equals(type)) {
            contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        }

        final String selection = "_id=?";
        final String[] selectionArgs = new String[] {split[1]};
        return getDataColumn(context, contentUri, selection, selectionArgs);
    }
    String[] projection = { MediaStore.Images.Media.DATA };
    Cursor imageCursor = ((Activity)context).managedQuery(uri, projection, null, null, null);
    int actual_image_column_index = imageCursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    imageCursor.moveToFirst();
    String img_path = imageCursor.getString(actual_image_column_index);
    String end = img_path.substring(img_path.length() - 4);
    if (0 != end.compareToIgnoreCase(".jpg") && 0 != end.compareToIgnoreCase(".png")) {
        return null;
    }
    return img_path;
}

imageUtil类中的decodeimage()方法.

 public Bitmap decodeImage(String path) {
        Bitmap res;
        try {
            ExifInterface exif = new ExifInterface(path);
            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

            BitmapFactory.Options op = new BitmapFactory.Options();
            op.inSampleSize = 1;
            op.inJustDecodeBounds = false;
            res = BitmapFactory.decodeFile(path, op);
            Matrix matrix = new Matrix();

            if (orientation == ExifInterface.ORIENTATION_ROTATE_90) {
                matrix.postRotate(90);
            } else if (orientation == ExifInterface.ORIENTATION_ROTATE_180) {
                matrix.postRotate(180);
            } else if (orientation == ExifInterface.ORIENTATION_ROTATE_270) {
                matrix.postRotate(270);
            }

            Bitmap temp = Bitmap.createBitmap(res, 0, 0, res.getWidth(), res.getHeight(), matrix, true);
            Log.i(TAG, "check target Image:" + temp.getWidth() + "*" + temp.getHeight());

            if (!temp.equals(res)) {
                res.recycle();
            }
            return temp;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

上面内容与OpenCV毫无关系,纯Android内容

进入OpenCV 测试

其实就几行代码,因为都是用api.

核心内容:灰度化,网上都有.

 public void processGray()
    {
        Mat src=new Mat();
        Mat dst=new Mat();
        Bitmap tmp=selectBitmap.copy(selectBitmap.getConfig(),true);
        dstBitmap= Bitmap.createBitmap(tmp.getWidth(),tmp.getHeight(), Bitmap.Config.RGB_565);
        Utils.bitmapToMat(selectBitmap,src);
        Imgproc.cvtColor(src,dst,Imgproc.COLOR_BGRA2GRAY);
        Utils.matToBitmap(dst,dstBitmap);
    }