數據類型轉換

1. byte[ ] 轉 int （高位在前 ，低位在後）

public int byteToInt( byte a, byte b, byte c, byte d ){

    return  ( a & 0xff )  |

                  ( b & 0xff ) << 8 |

                  ( c & 0xff ) << 16 |

                  ( d & 0xff ) << 24 ;

}

2. 將nv21圖片轉bitmap

byte[] nv21Picture ;
YuvImage image = new YuvImage(nv21Picture, ImageFormat.NV21, 720, 1280, null);//b2
ByteArrayOutputStream out = new ByteArrayOutputStream(nv21Picture.length);//b2

image.compressToJpeg(new Rect(0, 0, 720, 1280), 100, out);
byte[] tmp = out.toByteArray();
Bitmap bitmap = BitmapFactory.decodeByteArray(tmp, 0,tmp.length);