图片压缩无bug版

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package com.example.imageresizer;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;

import com.example.imageresizer.utils.ImageResizer;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class MainActivity extends AppCompatActivity {

private ImageView ivIcon;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    ivIcon = (ImageView) findViewById(R.id.ivIcon);}public void btnLoadImge(View v){    loadImage("http://20.1.4.181:8080/beautiful.jpg",100,100);}/** * 加载图片，并压缩 * @param imgPath * @param requestWidth * @param requestHeight */public void loadImage(String imgPath, final int requestWidth, final int requestHeight){    new AsyncTask<String,Void,Bitmap>(){        @Override        protected void onPostExecute(Bitmap bitmap) {            super.onPostExecute(bitmap);            if(bitmap != null){                ivIcon.setImageBitmap(bitmap);            }        }        @Override        protected Bitmap doInBackground(String... params) {            try {                //得到图片路径                String path = params[0];                URL url = new URL(path);                HttpURLConnection connection = (HttpURLConnection) url.openConnection();                connection.setRequestMethod("GET");                connection.setConnectTimeout(5000);                connection.setReadTimeout(5000);                connection.setDoInput(true);                connection.setDoOutput(true);                int code = connection.getResponseCode();                if(code == 200){                    //得到图片流                   InputStream is = connection.getInputStream();                    //解析图片                    BitmapFactory.Options options = new BitmapFactory.Options();                    //让图片暂时不去解析 只需要获取图片的宽高                    options.inJustDecodeBounds = true;                    //解析一下图片，这个时候，只会解析图片的宽*高                    BitmapFactory.decodeStream(is,null,options);                    //计算采样率                    options.inSampleSize = ImageResizer.calculateInSampleSize(options,requestWidth,requestHeight);                    //我这时候需要真正去解析图片                    options.inJustDecodeBounds = false;                    //关闭流                    is.close();                    //得到图片的输入流                    is = url.openStream();                    //解析图片的时候，才会去真正解析                    Bitmap bitmap = BitmapFactory.decodeStream(is,null,options);                    //关闭流                    is.close();                    return bitmap;                }            } catch (Exception e) {                e.printStackTrace();            }            return null;        }    }.execute(imgPath);}

}

计算采样率的工具类
package com.example.imageresizer.utils;

import android.graphics.BitmapFactory;

public class ImageResizer {

/** * 计算采样率 * @param options * @param requestWidth * @param requestHeight * @return */public static int calculateInSampleSize(BitmapFactory.Options options,int requestWidth,int requestHeight){    //获取图片的真实的宽高    int width = options.outWidth;    int height = options.outHeight;    int inSampleSize = 1;    options.inSampleSize = inSampleSize;//默认 1  1代表不对图片进行任何压缩    //计算采样率    if(width > requestWidth || height > requestHeight){        int halfWidth = width / 2;        int halfHeight = height / 2;        while((halfWidth / inSampleSize) >= requestWidth &&                (halfHeight / inSampleSize) >= requestHeight){            //计算采样率            inSampleSize *= 2;        }    }    return inSampleSize;}

}

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