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 > 100 || height > 100) {
int halfWidth = width / 2;
int halfHeight = height / 2;
while ((halfWidth / inSampleSize) >= 100 && (halfHeight / inSampleSize) >= 100) {
//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);
}
}
Android.Manifest加网络权限
最后调用这个类的方法,参数一图片地址,参数二控件名称。
安卓代码实现图片二次采样
最新推荐文章于 2021-03-13 09:00:13 发布