android 图片压缩，base64转换上传

可以把1.5M的压缩到100Kb这样哦，可以看到最后log，压缩后的大小为100kb以内

github地址：https://github.com/George-Soros/ImageTest

package com.tj.imagetest;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import butterknife.Bind;
import butterknife.ButterKnife;
import uk.co.senab.photoview.PhotoView;
import uk.co.senab.photoview.PhotoViewAttacher;

public class MainActivity extends AppCompatActivity {

    @Bind(R.id.btn_photo)
    Button mBtnPhoto;
    @Bind(R.id.img_photo)
    PhotoView mPhotoView;

    private Uri mImageUri; //图片路径Uri
    private String mImagePath;
    private String mFileName; //图片名称
    public static final int TAKE_PHOTO = 1;
    public static final int CROP_PHOTO = 2;
    private Bitmap mBitmap;
    private PhotoViewAttacher mAttacher;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ButterKnife.bind(this);
        mBtnPhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startCamera();
            }
        });
    }

    /***
    * 启动相机去拍摄, 并截图
    *
    */
    public void startCamera(){
        //图片名称 时间命名
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
        Date date = new Date(System.currentTimeMillis());
        mFileName = format.format(date);
        Log.d("data", "mFileName=" + mFileName);

        //存储至DCIM文件夹
        File path = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_DCIM);
        File outputImage = new File(path, mFileName +".jpg");
        try {
            if(outputImage.exists()) {
                outputImage.delete();
            }
            outputImage.createNewFile();
            mImagePath = path + "/"+ mFileName + ".jpg";
            Log.d("data","mImagePath="+mImagePath);
        } catch(IOException e) {
            e.printStackTrace();
        }
        //将File对象转换为Uri并启动照相程序
        mImageUri = Uri.fromFile(outputImage);
        Intent intent = new Intent("android.media.action.IMAGE_CAPTURE"); //照相
        intent.putExtra(MediaStore.EXTRA_OUTPUT, mImageUri); //指定图片输出地址
        startActivityForResult(intent,CROP_PHOTO); //启动照相
        //拍完照startActivityForResult() 结果返回onActivityResult()函数
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode != RESULT_OK) {
            return;
        }
        switch(requestCode) {
            case TAKE_PHOTO:
                Intent intent = new Intent("com.android.camera.action.CROP"); //剪裁
                intent.setDataAndType(mImageUri, "image/*");
                intent.putExtra("scale", true);
                //设置宽高比例
                intent.putExtra("aspectX", 1);
                intent.putExtra("aspectY", 1);
                //设置裁剪图片宽高
                intent.putExtra("outputX", 400);
                intent.putExtra("outputY", 340);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, mImageUri);
                //广播刷新相册
                Intent intentBc = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
                intentBc.setData(mImageUri);
                this.sendBroadcast(intentBc);
                startActivityForResult(intent, CROP_PHOTO); //设置裁剪参数显示图片至ImageView
                break;
            case CROP_PHOTO:
                try {
                    //图片解析成Bitmap对象
                    mBitmap = BitmapFactory.decodeStream(
                            getContentResolver().openInputStream(mImageUri));
                    mAttacher = new PhotoViewAttacher(mPhotoView);
                    mPhotoView.setImageBitmap(mBitmap);
                    mAttacher.update();

                    //file:///storage/emulated/0/DCIM/20160707132811.jpg
                    Log.d("d","mImagePath="+mImagePath);

                    ImageUtils.bitmapToString(mImagePath);

                } catch(FileNotFoundException e) {
                    e.printStackTrace();
                }
                break;
            default:
                break;
        }
    }

}

package com.tj.imagetest;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;
import android.util.Log;

import java.io.ByteArrayOutputStream;

/**
* Created by Administrator on 2016/7/7 0007.
*/
public class ImageUtils {

    // 根据路径获得图片并压缩，返回bitmap用于显示
    public static Bitmap getSmallBitmap(String filePath) {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(filePath, options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, 480, 800);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;

        return BitmapFactory.decodeFile(filePath, options);
    }

    //计算图片的缩放值
    public static int calculateInSampleSize(BitmapFactory.Options options,int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height/ (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        return inSampleSize;
    }

//把bitmap转换成String
public static String bitmapToString(String filePath) {
    Bitmap bm = getSmallBitmap(filePath);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    //1.5M的压缩后在100Kb以内，测试得值,压缩后的大小=94486字节,压缩后的大小=74473字节
    //这里的JPEG 如果换成PNG，那么压缩的就有600kB这样
    bm.compress(Bitmap.CompressFormat.JPEG, 40, baos);
    byte[] b = baos.toByteArray();
    Log.d("d", "压缩后的大小=" + b.length);
    return Base64.encodeToString(b, Base64.DEFAULT);
}

    
}

其中PhotoView不明白，看http://www.jianshu.com/p/6e38712e310f