android-bitmap低质量问题

时间:2015-08-18 08:07:11

标签: java android xml bitmap

我刚创建了一些从相机拍摄照片并将结果图像放入imageview的功能。而我发现我的拍摄质量非常糟糕。

以下是一些代码:

 @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == CAMERA_REQUEST && resultCode == RESULT_OK) {
            Bitmap photo = (Bitmap) data.getExtras().get("data");
            picture.setImageBitmap(photo);
        }
    }

View.OnClickListener camerabtnlistener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            startActivityForResult(cameraIntent, CAMERA_REQUEST);
        }
    };


@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_admin_help_3);
        btnPicture = (Button) findViewById(R.id.btnPicture);
        picture= (ImageView) findViewById(R.id.picture);
        mToolbar = (Toolbar) findViewById(R.id.toolbar);
        layoutPic = (RelativeLayout) findViewById(R.id.layoutPic);
        setSupportActionBar(mToolbar);

        getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_HOME, ActionBar.DISPLAY_SHOW_CUSTOM);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setHomeButtonEnabled(true);

        btnPicture.setOnClickListener(camerabtnlistener);

    }

和xml

<ImageView
            android:id="@+id/picture"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:src="@drawable/test_admin_big"
            android:adjustViewBounds="true"/>

我已经在下面尝试过这些解决方案了,但那不起作用

  1. Resizing ImageView to fit to aspect ratio
  2. Fit image into ImageView, keep aspect ratio and then resize ImageView to image dimensions?
  3. Android bitmap quality issues
  4. 请告知

    谢谢

2 个答案:

答案 0 :(得分:5)

如果你使用Bundle extras = data.getExtras();在你的onActivityResult中,它将返回缩略图而不是实际图像。

以下是我用于捕获和保存摄像机图像然后将其显示到imageview的代码。

您必须将相机图像保存到特定位置,然后从该位置获取。

这是打开拍摄相机图像活动的方法。

private static final int CAMERA_PHOTO = 111;
private Uri imageToUploadUri;

private void captureCameraImage() {
        Intent chooserIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        File f = new File(Environment.getExternalStorageDirectory(), "POST_IMAGE.jpg");
        chooserIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f));
        imageToUploadUri = Uri.fromFile(f);
        startActivityForResult(chooserIntent, CAMERA_PHOTO);
    }

那么你的onActivityResult()方法应该是这样的。

  @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);

            if (requestCode == CAMERA_PHOTO && resultCode == Activity.RESULT_OK) {
                if(imageToUploadUri != null){
                    Uri selectedImage = imageToUploadUri;
                    getContentResolver().notifyChange(selectedImage, null);
                    Bitmap reducedSizeBitmap = getBitmap(imageToUploadUri.getPath());
                    if(reducedSizeBitmap != null){
                        imageview.setImageBitmap(reducedSizeBitmap);
                    }else{
                        Toast.makeText(this,"Error while capturing Image",Toast.LENGTH_LONG).show();
                    }
                }else{
                    Toast.makeText(this,"Error while capturing Image",Toast.LENGTH_LONG).show();
                }
            } 
        }

这是onActivityResult()中使用的getBitmap()方法。

private Bitmap getBitmap(String path) {

        Uri uri = Uri.fromFile(new File(path));
        InputStream in = null;
        try {
            final int IMAGE_MAX_SIZE = 1200000; // 1.2MP
            in = getContentResolver().openInputStream(uri);

            // Decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(in, null, o);
            in.close();


            int scale = 1;
            while ((o.outWidth * o.outHeight) * (1 / Math.pow(scale, 2)) >
                    IMAGE_MAX_SIZE) {
                scale++;
            }
            Log.d("", "scale = " + scale + ", orig-width: " + o.outWidth + ", orig-height: " + o.outHeight);

            Bitmap b = null;
            in = getContentResolver().openInputStream(uri);
            if (scale > 1) {
                scale--;
                // scale to max possible inSampleSize that still yields an image
                // larger than target
                o = new BitmapFactory.Options();
                o.inSampleSize = scale;
                b = BitmapFactory.decodeStream(in, null, o);

                // resize to desired dimensions
                int height = b.getHeight();
                int width = b.getWidth();
                Log.d("", "1th scale operation dimenions - width: " + width + ", height: " + height);

                double y = Math.sqrt(IMAGE_MAX_SIZE
                        / (((double) width) / height));
                double x = (y / height) * width;

                Bitmap scaledBitmap = Bitmap.createScaledBitmap(b, (int) x,
                        (int) y, true);
                b.recycle();
                b = scaledBitmap;

                System.gc();
            } else {
                b = BitmapFactory.decodeStream(in);
            }
            in.close();

            Log.d("", "bitmap size - width: " + b.getWidth() + ", height: " +
                    b.getHeight());
            return b;
        } catch (IOException e) {
            Log.e("", e.getMessage(), e);
            return null;
        }
    }

我希望它有所帮助!

答案 1 :(得分:0)

而不是简单地创建自己的文件夹&amp;在为相机创建意图时给出它的uri,例如:                Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); fileUri = GetOutpoutMediaFileUri.getOutputMediaFileUri(MEDIA_TYPE_IMAGE); intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); startActivityForResult(intent, 0)