图片二次采样

来源：互联网发布：听歌软件排行编辑：程序博客网时间：2024/06/05 01:05
import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.AsyncTask;import android.widget.ImageView;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;public class TwoImageUtils {        public static void loadImage(String path, final ImageView imageView) {            new AsyncTask<String, Void, Bitmap>() {                @Override                protected void onPostExecute(Bitmap bitmap) {                    super.onPostExecute(bitmap);                    if (bitmap != null)                        imageView.setImageBitmap(bitmap);                    else                        imageView.setImageResource(R.drawable.ic_launcher);                }                @Override                protected Bitmap doInBackground(String... params) {                    try {                        String path = params[0];                        URL url = new URL(path);                        HttpURLConnection connection = (HttpURLConnection) url.openConnection();                        connection.setRequestMethod("GET");                        connection.setConnectTimeout(5000);                        connection.setReadTimeout(5000);                        int code = connection.getResponseCode();                        if (code == 200) {                            //得到图片数据                            InputStream is = connection.getInputStream();                            //BitmapFactory.decodeStream(is);//ARGB_888 一个像素占 4个字节  ARGB_565 一个像素占 2 个字节  Alpha Red、Green、Blue(颜色)                            BitmapFactory.Options options = new BitmapFactory.Options();                            //在图片真正解析之前，不要解析图片数据，只需要告诉一下转换器，只要获取图片的像素(宽高)                            options.inJustDecodeBounds = true;                           //告诉BitmapFactory转换工厂不去真正解析图片只需要拿到图片宽高就行                            //假解析 API 有bug                            BitmapFactory.decodeStream(is, null, options);                            //压缩，根据图片采样率进行二次采样   100 * 100 是你所期望的具体图片尺寸                            //options.inSampleSize = 2; //采样用来计算图片的宽高(1920 * 1080 -> 1920 / 2 1080 / 2)                            //获取图片宽高，注意：图片的原始宽高                            int width = options.outWidth;                            int height = options.outHeight;                            System.out.println("宽:" + width + "高 ： " + height);                            //定义一个变量去记住我们采样率                            int inSampleSize = 1;//默认是1 ,即不对图片进行任何压缩                            if (width > 50 || height > 50) {                                int halfWidth = width / 2;                                int halfHeight = height / 2;                                while ((halfWidth / inSampleSize) >= 50 && (halfHeight / inSampleSize) >= 50) {                                    //计算采样率                                    inSampleSize *= 2;                                }                            }                            //采样率改变了                            options.inSampleSize = inSampleSize;// 8                            //图片压缩完之后，放行图片解析                            options.inJustDecodeBounds = false;//告诉图片转换工厂，可以解析图片了                            //关闭之前的流                            is.close();                            //重新再去得到当前这张图片的字节流数据                            is = url.openStream();                            //开始解析图片                            Bitmap bitmap = BitmapFactory.decodeStream(is, null, options);                            //关闭流                            is.close();                            // Bitmap bitmap = BitmapFactory.decodeStream(is);                            return bitmap;                        }                    } catch (Exception e) {                        e.printStackTrace();                    }                    return null;                }            }.execute(path);        }    }
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