图片(Image)压缩

来源：互联网发布：clipstudiopaint mac 编辑：程序博客网时间：2024/05/01 23:25

网络访问权限

   <uses-permission android:name="android.permission.INTERNET"/>

MainActivity

public class MainActivity extends AppCompatActivity {    private ImageView ivIcon;    @Override    protected 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);                    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

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;    }}

xml布局

 <Button        android:onClick="btnLoadImge"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="加载图片(压缩)"/>    <ImageView        android:id="@+id/ivIcon"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />

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