我必须上传图像，可以从图库中选择，也可以用相机拍摄。我已经成功地做到了。但问题是，有时图像大小是1MB。所以上传到服务器需要更多的时间。我需要在上传之前调整此图像的大小。如何做到这一点？
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
AlertDialog alertDialog1;
if( requestCode == REQUEST_IMAGE && resultCode == Activity.RESULT_OK ){
try {
FileInputStream in = new FileInputStream(destination);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 10;
imagePath = destination.getAbsolutePath();
Bitmap bmp = BitmapFactory.decodeStream(in, null, options);
//img = (ImageView) findViewById(R.id.imageView1);
int nh = (int) ( bmp.getHeight() * (512.0 / bmp.getWidth()) );
Bitmap scaled = Bitmap.createScaledBitmap(bmp, 512, nh, true);
img.setImageBitmap(scaled);
} catch (Exception e) {
// AlertDialog alertDialog1;
alertDialog1 = new AlertDialog.Builder(getActivity()).create();
alertDialog1.setTitle("Message");
alertDialog1.setMessage("bala t "+e.toString());
alertDialog1.show();
}
}else if (requestCode == 1) {
try {
Uri selectedImageUri = data.getData();
imagePath = getPath(selectedImageUri);
destination = new File(imagePath);
FileInputStream in = new FileInputStream(destination);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 10;
imagePath = destination.getAbsolutePath();
Bitmap bmp = BitmapFactory.decodeStream(in, null, options);
//int nh = (int) ( bmp.getHeight() * (512.0 / bmp.getWidth()) );
// Bitmap scaled = Bitmap.createScaledBitmap(bmp, 512, nh, true);
img.setImageBitmap(bmp);
//img.setImageBitmap(bmp);
} catch (Exception e) {
// AlertDialog alertDialog1;
alertDialog1 = new AlertDialog.Builder(getActivity()).create();
alertDialog1.setTitle("Message");
alertDialog1.setMessage("sangt"+e.toString());
alertDialog1.show();
}
}
else{
}
}
现在，如何调整图像大小？
-
要调整图像大小，可以使用以下功能
Bitmap yourBitmap; Bitmap resized = Bitmap.createScaledBitmap(yourBitmap, newWidth, newHeight, true); -
压缩图像
Bitmap bmp = BitmapFactory.decodeFile(miFoto) ByteArrayOutputStream bos = new ByteArrayOutputStream(); bmp.compress(CompressFormat.JPEG, 70, bos); InputStream in = new ByteArrayInputStream(bos.toByteArray()); ContentBody foto = new InputStreamBody(in, "image/jpeg", "filename");
您可以签出此代码，它的工作原理与您想要的WhatsApp Like Image Compression相同。此代码已根据我的使用情况进行了修改。使用此代码将为您提供：
- 100kb左右的低尺寸图像，而不使用图像质量
- 高像素图像将缩小到maxWidth和maxHeight，而不会失去其原始质量
原创文章：加载图像超级快像WhatsApp
演示：
原始图像：尺寸-3.84Mb尺寸-3120*4160
压缩图像：大小-157Kb尺寸-960*1280
您需要压缩图像，因为重新缩放位图会降低图像质量。你可以试试这个功能来压缩你的图像。只需从你在活动中上传图片的地方传递这个乐趣。
/ Funtion for compress image
public String compressImage(String imageUri) {
String filePath = getRealPathFromURI(imageUri);
Bitmap scaledBitmap = null;
BitmapFactory.Options options = new BitmapFactory.Options();
// by setting this field as true, the actual bitmap pixels are not loaded in the memory. Just the bounds are loaded. If
// you try the use the bitmap here, you will get null.
options.inJustDecodeBounds = true;
Bitmap bmp = BitmapFactory.decodeFile(filePath, options);
int actualHeight = options.outHeight;
int actualWidth = options.outWidth;
// max Height and width values of the compressed image is taken as 816x612
float maxHeight = 816.0f;
float maxWidth = 612.0f;
float imgRatio = actualWidth / actualHeight;
float maxRatio = maxWidth / maxHeight;
// width and height values are set maintaining the aspect ratio of the image
if (actualHeight > maxHeight || actualWidth > maxWidth) {
if (imgRatio < maxRatio) { imgRatio = maxHeight / actualHeight; actualWidth = (int) (imgRatio * actualWidth); actualHeight = (int) maxHeight; } else if (imgRatio > maxRatio) {
imgRatio = maxWidth / actualWidth;
actualHeight = (int) (imgRatio * actualHeight);
actualWidth = (int) maxWidth;
} else {
actualHeight = (int) maxHeight;
actualWidth = (int) maxWidth;
}
}
// setting inSampleSize value allows to load a scaled down version of the original image
options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);
// inJustDecodeBounds set to false to load the actual bitmap
options.inJustDecodeBounds = false;
// this options allow android to claim the bitmap memory if it runs low on memory
options.inPurgeable = true;
options.inInputShareable = true;
options.inTempStorage = new byte[16 * 1024];
try {
// load the bitmap from its path
bmp = BitmapFactory.decodeFile(filePath, options);
} catch (OutOfMemoryError exception) {
exception.printStackTrace();
}
try {
scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight,Bitmap.Config.ARGB_8888);
} catch (OutOfMemoryError exception) {
exception.printStackTrace();
}
float ratioX = actualWidth / (float) options.outWidth;
float ratioY = actualHeight / (float) options.outHeight;
float middleX = actualWidth / 2.0f;
float middleY = actualHeight / 2.0f;
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);
Canvas canvas = new Canvas(scaledBitmap);
canvas.setMatrix(scaleMatrix);
canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2, middleY - bmp.getHeight() / 2, new Paint(Paint.FILTER_BITMAP_FLAG));
// check the rotation of the image and display it properly
ExifInterface exif;
try {
exif = new ExifInterface(filePath);
int orientation = exif.getAttributeInt(
ExifInterface.TAG_ORIENTATION, 0);
Log.d("EXIF", "Exif: " + orientation);
Matrix matrix = new Matrix();
if (orientation == 6) {
matrix.postRotate(90);
Log.d("EXIF", "Exif: " + orientation);
} else if (orientation == 3) {
matrix.postRotate(180);
Log.d("EXIF", "Exif: " + orientation);
} else if (orientation == 8) {
matrix.postRotate(270);
Log.d("EXIF", "Exif: " + orientation);
}
scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix, true);
} catch (IOException e) {
e.printStackTrace();
}
FileOutputStream out = null;
String filename = getFilename();
try {
out = new FileOutputStream(filename);
// write the compressed bitmap at the destination specified by filename.
scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return filename;
}
public String getFilename() {
File file = new File(Environment.getExternalStorageDirectory().getPath(), "MyFolder/Images");
if (!file.exists()) {
file.mkdirs();
}
String uriSting = (file.getAbsolutePath() + "/" + System.currentTimeMillis() + ".jpg");
return uriSting;
}
private String getRealPathFromURI(String contentURI) {
Uri contentUri = Uri.parse(contentURI);
Cursor cursor = getContentResolver().query(contentUri, null, null, null, null);
if (cursor == null) {
return contentUri.getPath();
} else {
cursor.moveToFirst();
int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
return cursor.getString(index);
}
}
public int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int heightRatio = Math.round((float) height/ (float) reqHeight);
final int widthRatio = Math.round((float) width / (float) reqWidth);
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio; } final float totalPixels = width * height; final float totalReqPixelsCap = reqWidth * reqHeight * 2; while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
inSampleSize++;
}
return inSampleSize;
}
//
private void previewMedia(boolean isImage) {
// Checking whether captured media is image or video
if (isImage) {
photo.setVisibility(View.VISIBLE);
// vidPreview.setVisibility(View.GONE);
// bimatp factory
BitmapFactory.Options options = new BitmapFactory.Options();
// down sizing image as it throws OutOfMemory Exception for larger
// images
options.inSampleSize = 2;
final Bitmap bitmap = BitmapFactory.decodeFile(filePath, options);
options.inJustDecodeBounds = true;
photo.setImageBitmap(bitmap);
}
}
像一样压缩位图
bmp = Bitmap.createScaledBitmap(bmp, 160, 160, true);
可以使用：
Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath());
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 50, stream); //compress to 50% of original image quality
byte[] byte_arr = stream.toByteArray();