Android 图片压缩的一些小技巧，以及bitmap和byte[]之间的转换

public byte[] compressBitmap(Bitmap bitmap) {
ByteArrayOutputStream baos = null;
try {
baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
baos.close();
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
byte[] buffer = baos.toByteArray();
BitmapFactory.decodeByteArray(buffer, 0, buffer.length, options);
int outWidth = options.outWidth;
int scale = outWidth / WIDTH;
if (scale > 1) {
options.inSampleSize = scale;
options.inJustDecodeBounds = false;
Bitmap tempBitmap = BitmapFactory.decodeByteArray(buffer, 0, buffer.length, options);
baos = new ByteArrayOutputStream();
tempBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
baos.close();
}
return baos.toByteArray();
} catch (Exception e) {
return null;
} finally {
try {
if (baos != null) {
baos.close();
}
} catch (IOException e) {
return null;
}
}
}

public byte[] compressBitmap(byte[] buffer) {
if (buffer == null || buffer.length == 0) {
return null;
}
ByteArrayOutputStream baos = null;
try {
// 只获取图片的大小信息，而不是将整张图片载入在内存中，避免内存溢出
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(buffer, 0, buffer.length, options);
int outWidth = options.outWidth;
int scale = outWidth / WIDTH;
if (scale > 1) {
options.inSampleSize = scale;
options.inJustDecodeBounds = false;
Bitmap bitmap = BitmapFactory.decodeByteArray(buffer, 0, buffer.length, options);
baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
return baos.toByteArray();
} else {
return buffer;
}
} catch (Exception e) {
return null;
} catch (OutOfMemoryError e) {
return null;
} finally {
try {
if (baos != null) {
baos.close();
}
} catch (IOException e) {
return null;
}
}
}

public Bitmap compressBitmap(String path) {
Bitmap bitmap = null;
try {
bitmap = BitmapFactory.decodeFile(path);
int scale = 1;
if(bitmap.getWidth() > bitmap.getHeight()){
//横向拍摄的照片
scale = bitmap.getHeight() / WIDTH;
}else{
//竖屏拍摄的照片
scale = bitmap.getWidth() / WIDTH;
}
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inJustDecodeBounds = false;
if (scale > 1) {
//压缩到1/scale
opt.inSampleSize = scale;
bitmap = BitmapFactory.decodeFile(path, opt);
} [b]else {
bitmap = BitmapFactory.decodeFile(path, opt);
}
} catch (OutOfMemoryError e) {
return null;
}
return bitmap;
}

public byte[] bitmapToByte(Bitmap bitmap) {
ByteArrayOutputStream bos = null;
try {
if (bitmap == null) {
return null;
}
bos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
return bos.toByteArray();

} catch (Exception e) {
return null;
} catch (OutOfMemoryError e) {
return null;
} finally {
try {
if (bos != null)
bos.close();
} catch (IOException e) {
return null;
}
}
}