android图片压缩总结

public static void compressBmpToFile(Bitmap bmp,File file){
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		int options = 80;//个人喜欢从80开始,
		bmp.compress(Bitmap.CompressFormat.JPEG, options, baos);
		while (baos.toByteArray().length / 1024 > 100) { 
			baos.reset();
			options -= 10;
			bmp.compress(Bitmap.CompressFormat.JPEG, options, baos);
		}
		try {
			FileOutputStream fos = new FileOutputStream(file);
			fos.write(baos.toByteArray());
			fos.flush();
			fos.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

2.   将图片从本地读到内存时,进行压缩 ,即图片从File形式变为Bitmap形式

private Bitmap compressBmpFromBmp(Bitmap image) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		int options = 100;
		image.compress(Bitmap.CompressFormat.JPEG, 100, baos);
		while (baos.toByteArray().length / 1024 > 100) { 
			baos.reset();
			options -= 10;
			image.compress(Bitmap.CompressFormat.JPEG, options, baos);
		}
		ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());
		Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);
		return bitmap;
	}

再看一个方法:

private Bitmap compressImageFromFile(String srcPath) {
		BitmapFactory.Options newOpts = new BitmapFactory.Options();
		newOpts.inJustDecodeBounds = true;//只读边,不读内容
		Bitmap bitmap = BitmapFactory.decodeFile(srcPath, newOpts);

		newOpts.inJustDecodeBounds = false;
		int w = newOpts.outWidth;
		int h = newOpts.outHeight;
		float hh = 800f;//
		float ww = 480f;//
		int be = 1;
		if (w > h && w > ww) {
			be = (int) (newOpts.outWidth / ww);
		} else if (w < h && h > hh) {
			be = (int) (newOpts.outHeight / hh);
		}
		if (be <= 0)
			be = 1;
		newOpts.inSampleSize = be;//设置采样率
		
		newOpts.inPreferredConfig = Config.ARGB_8888;//该模式是默认的,可不设,设了可以装13
		newOpts.inPurgeable = true;// 同时设置才会有效
		newOpts.inInputShareable = true;//。当系统内存不够时候图片自动被回收
		
		bitmap = BitmapFactory.decodeFile(srcPath, newOpts);
		//return compressBmpFromBmp(bitmap);//原来的方法调用了这个方法企图进行二次压缩
					    		//其实是无效的,大家尽管尝试
		return bitmap;