android 相册选择图片图片的压缩

谁借莪１个温暖的怀抱￠ 2022-07-15 06:26 295阅读 0赞

app 开发中图片的加载和上传是经常使用到的，如果加载的图片过大，可能会出现oom内存溢出

这是就需要我进行图片宽高，和图片大少（质量）的压缩

public void clickPhoto(View view){
            Intent intent = new Intent();
            intent.setAction(Intent.ACTION_PICK);
            intent.setType("image/*");
            startActivityForResult(intent,image_request_code);
        }
    
        private Bitmap ImageMassCompress(Bitmap btm){
            int mass = 100;
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            //第一个参数是jpeg的图片格式，第二参数要压缩到的百分比100%不变，写入到一个输出流中
            btm.compress(Bitmap.CompressFormat.JPEG,mass,outputStream);
    
            //指定压缩图片的大少不超过500k
            int targer = 500*1024;
            int length = outputStream.toByteArray().length;
            if(length > targer){
                mass = length * 100 /targer;//指定压缩的百分比
            }
            btm.compress(Bitmap.CompressFormat.JPEG,mass,outputStream);
            //读取输出流
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(outputStream.toByteArray());
            //通过bitmapfactory进行解析
            Bitmap bitmap = BitmapFactory.decodeStream(byteArrayInputStream);
            return bitmap;
        }
    
        private Bitmap ImageSizeCompress(Uri uri){
            InputStream Stream = null;
            InputStream inputStream = null;
            try {
                //根据uri获取图片的流
                 inputStream = getContentResolver().openInputStream(uri);
                BitmapFactory.Options options = new BitmapFactory.Options();
                //options的in系列的设置了，injustdecodebouond只解析图片的大小，而不加载到内存中去
                options.inJustDecodeBounds = true;
    
                //1.如果通过options.outHeight获取图片的宽高，就必须通过decodestream解析同options赋值
                //否则options.outheight获取不到宽高
                BitmapFactory.decodeStream(inputStream,null,options);
                //2.通过 btm.getHeight()获取图片的宽高就不需要1的解析，我这里采取第一张方式
    //            Bitmap btm = BitmapFactory.decodeStream(inputStream);
                //以屏幕的宽高进行压缩
                DisplayMetrics displayMetrics = getResources().getDisplayMetrics();
                int heightPixels = displayMetrics.heightPixels;
                int widthPixels = displayMetrics.widthPixels;
                //获取图片的宽高
                int outHeight = options.outHeight;
                int outWidth = options.outWidth;
                //heightPixels就是要压缩后的图片高度，宽度也一样
                int a = (int) Math.ceil((outHeight/(float)heightPixels));
                int b = (int) Math.ceil(outWidth/(float)widthPixels);
                //比例计算,一般是图片比较大的情况下进行压缩
                int max = Math.max(a, b);
                if(max > 1){
                    options.inSampleSize = max;
                }
                //解析到内存中去
                options.inJustDecodeBounds = false;
    //            根据uri重新获取流，inputstream在解析中发生改变了
                 Stream = getContentResolver().openInputStream(uri);
                Bitmap bitmap = BitmapFactory.decodeStream(Stream, null, options);
                return bitmap;
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                try {
                    if(inputStream != null) {
                        inputStream.close();
                    }
                    if(Stream != null){
                        Stream.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
    
            }
            return  null;
    
        }
    
        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
    
            if(resultCode == RESULT_OK){
                switch (requestCode){
                    case image_request_code:
                        if(data != null){
                            //从相册中获取到图片的路径，图片所在文件夹
                            Uri uri = data.getData();
                            Bitmap bitmap = ImageSizeCompress(uri);
                            if(bitmap != null){
                                Bitmap btm = ImageMassCompress(bitmap);
                            }
                        }
                        break;
                }
            }
        }