Android个人中心的头像上传，图片编码及截取实例

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

  private ImageView iv_img;
  private Button bt_camera;
  private Button bt_xiangce;
  private static final int PHOTO_REQUEST_CAREMA = 1;// 拍照
  private static final int PHOTO_REQUEST_GALLERY = 2;// 从相册中选择
  private static final int PHOTO_REQUEST_CUT = 3;// 结果
  /* 头像名称 */
  private static final String PHOTO_FILE_NAME = "temp_photo.jpg";
  private File tempFile;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //加载控件
    initView();
  }

  private void initView() {
    iv_img = (ImageView) findViewById(R.id.iv_img);
    bt_camera = (Button) findViewById(R.id.bt_camera);
    bt_xiangce = (Button) findViewById(R.id.bt_xiangce);
    //从SharedPreferences获取图片
    getBitmapFromSharedPreferences();
    //监听两个按钮，相册按钮和相机按钮
    bt_camera.setOnClickListener(this);
    bt_xiangce.setOnClickListener(this);
  }

  @Override
  public void onClick(View v) {
    switch (v.getId()) {
      case R.id.bt_camera:
        // 激活相机
        Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
        // 判断存储卡是否可以用，可用进行存储
        if (hasSdcard()) {
          tempFile = new File(Environment.getExternalStorageDirectory(), PHOTO_FILE_NAME);
          // 从文件中创建uri
          Uri uri = Uri.fromFile(tempFile);
          intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
        }
        // 开启一个带有返回值的Activity，请求码为PHOTO_REQUEST_CAREMA
        startActivityForResult(intent, PHOTO_REQUEST_CAREMA);
        break;
      case R.id.bt_xiangce:
        // 激活系统图库，选择一张图片
        Intent intent1 = new Intent(Intent.ACTION_PICK);
        intent1.setType("image/*");
        // 开启一个带有返回值的Activity，请求码为PHOTO_REQUEST_GALLERY
        startActivityForResult(intent1, PHOTO_REQUEST_GALLERY);
        break;
    }
  }
  /*
   * 判断sdcard是否被挂载
   */
  private boolean hasSdcard() {
    //判断ＳＤ卡手否是安装好的　　　media_mounted
    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
      return true;
    } else {
      return false;
    }
  }

  /*
   * 剪切图片
   */
  private void crop(Uri uri) {
    // 裁剪图片意图
    Intent intent = new Intent("com.android.camera.action.CROP");
    intent.setDataAndType(uri, "image/*");
    intent.putExtra("crop", "true");
    // 裁剪框的比例，1：1
    intent.putExtra("aspectX", 1);
    intent.putExtra("aspectY", 1);
    // 裁剪后输出图片的尺寸大小
    intent.putExtra("outputX", 250);
    intent.putExtra("outputY", 250);

    intent.putExtra("outputFormat", "JPEG");// 图片格式
    intent.putExtra("noFaceDetection", true);// 取消人脸识别
    intent.putExtra("return-data", true);
    // 开启一个带有返回值的Activity，请求码为PHOTO_REQUEST_CUT
    startActivityForResult(intent, PHOTO_REQUEST_CUT);
  }

  /**
   *
   * @param requestCode
   * @param resultCode
   * @param data
   */
  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == PHOTO_REQUEST_GALLERY) {
      // 从相册返回的数据
      if (data != null) {
        // 得到图片的全路径
        Uri uri = data.getData();
        crop(uri);
      }
    } else if (requestCode == PHOTO_REQUEST_CAREMA) {
      // 从相机返回的数据
      if (hasSdcard()) {
        crop(Uri.fromFile(tempFile));
      } else {
        Toast.makeText(MainActivity.this, "未找到存储卡，无法存储照片！", Toast.LENGTH_SHORT).show();
      }
    } else if (requestCode == PHOTO_REQUEST_CUT) {
      // 从剪切图片返回的数据
      if (data != null) {
        Bitmap bitmap = data.getParcelableExtra("data");
        /**
         * 获得图片
         */
        iv_img.setImageBitmap(bitmap);
        //保存到SharedPreferences
        saveBitmapToSharedPreferences(bitmap);
      }
      try {
        // 将临时文件删除
        tempFile.delete();
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
    super.onActivityResult(requestCode, resultCode, data);
  }

  //保存图片到SharedPreferences
  private void saveBitmapToSharedPreferences(Bitmap bitmap) {
    // Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
    //第一步:将Bitmap压缩至字节数组输出流ByteArrayOutputStream
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 80, byteArrayOutputStream);
    //第二步:利用Base64将字节数组输出流中的数据转换成字符串String
    byte[] byteArray = byteArrayOutputStream.toByteArray();
    String imageString = new String(Base64.encodeToString(byteArray, Base64.DEFAULT));
    //第三步:将String保持至SharedPreferences
    SharedPreferences sharedPreferences = getSharedPreferences("testSP", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString("image", imageString);
    editor.commit();

    //上传头像
    setImgByStr(imageString,"");
  }


  /**
   * 上传头像
   * @param imgStr
   * @param imgName
   */
  public void setImgByStr(String imgStr, String imgName) {
  //这里是头像接口，通过Post请求，拼接接口地址和ID，上传数据。
    String url = "http://这里写的是接口地址（具体接收格式要看后台怎么给）";
    Map<String, String> params = new HashMap<String, String>();
    params.put("id", "11111111");// 11111111
    params.put("data", imgStr);
    OkHttp.postAsync(url, params, new OkHttp.DataCallBack() {
      @Override
      public void requestFailure(Request request, IOException e) {
        Log.i("上传失败", "失败" + request.toString() + e.toString());
      }
      @Override
      public void requestSuccess(String result) throws Exception {
        Toast.makeText(MainActivity.this,"上传成功",Toast.LENGTH_SHORT).show();
        Log.i("上传成功", result);
      }
    });
  }

  //从SharedPreferences获取图片
  private void getBitmapFromSharedPreferences(){
    SharedPreferences sharedPreferences=getSharedPreferences("testSP", Context.MODE_PRIVATE);
    //第一步:取出字符串形式的Bitmap
    String imageString=sharedPreferences.getString("image", "");
    //第二步:利用Base64将字符串转换为ByteArrayInputStream
    byte[] byteArray= Base64.decode(imageString, Base64.DEFAULT);
    if(byteArray.length==0){
      iv_img.setImageResource(R.mipmap.ic_launcher);
    }else{
      ByteArrayInputStream byteArrayInputStream=new ByteArrayInputStream(byteArray);

      //第三步:利用ByteArrayInputStream生成Bitmap
      Bitmap bitmap= BitmapFactory.decodeStream(byteArrayInputStream);
      iv_img.setImageBitmap(bitmap);
    }

  }

}