android 图片、文件资源资源相关操…

android 图片、文件资源资源相关操作
 第一步:将图片转化字节数组.
   1.得到Bitmap对象
    BitmapbitMap = BitmapFactory.decodeResource(getResources(),
                                                        R.drawable.main_green);
   2.Bitmap ->byte[]
    byte[] picByte = getPicByte(bitMap,Bitmap.CompressFormat.PNG, 0);

    private byte[] getPicByte(Bitmap src, Bitmap.CompressFormatformat, int quality) {
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        src.compress(format, quality, os);

        byte[] array = os.toByteArray();
        return array;
   }
 第二步:字节数组写文件
   public  voidWriteFile(String url, String name, byte[] data) {
   FileOutputStream fOut = null;
    File file =createFile(url, name);
    try {
     fOut = new FileOutputStream(file);
     fOut.write(data);
     fOut.flush();
    } catch(Exception e) {
    e.printStackTrace();
    } finally{
    try {
    if (fOut != null) {
      fOut.close();
    }
   } catch(IOException e) {
    Log.e("tag", e.getMessage());
   }
  }
 }
   

  //private final Runtime r =Runtime.getRuntime();
  public File createFile(Stringpath, String name) {
  File temp, file = null;
  try {
    temp = newFile(path);
    if(!temp.exists()) {
    temp.mkdirs();
    }
  //   r.exec("chmod777 " + path);
   if (name ==null)
    returnnull;
   file = newFile(temp, name);
   if(!file.exists()) {
    try{
     file.createNewFile();
    }catch (IOException e) {
     Log.e("tag",e.getMessage());
    }
   }
//   r.exec("chmod777 " + (path + name));
  } catch (Exception e) {
   Log.e("tag",e.getMessage());
  }
  return file;
 }

获取本地资源其它方式 以txt文本资源为例
      private byte[] getTxtByte() {
  byte[] buffer = null;
  try {
    //gbk.txt文件存放在assets文件夹下
   InputStreamis = getAssets().open("gbk.txt");
   int size =is.available();
   buffer = newbyte[size];
   is.read(buffer);
   is.close();

  } catch (IOException e){
   throw newRuntimeException(e);
  }
  return buffer;
 }
  
   从sdcard获取资源显示.

    public void setPicture() {
  File file = newFile("/sdcard/picture/picurllsit/test.png");
  byte[] picByte =getBytesFromFile(file);
  imageView.setImageBitmap(Bytes2Bimap(picByte));
 }
       1.byte[] ->Bitmap
 private Bitmap Bytes2Bimap(byte[] b) {
  if (b.length != 0) {
   returnBitmapFactory.decodeByteArray(b, 0, b.length);
  } else{   
   returnnull;
  }
 }

       2.file-> byte[]
 private byte[] getBytesFromFile(File file){
  InputStream is = null;
  byte[] bytes = null;
  try {
   is = newFileInputStream(file);
   long length =file.length();
   if (length> Integer.MAX_VALUE) {
    Log.v("TAG","File is too large.....");
   }
   bytes = newbyte[(int) length];
   int offset =0;
   int numRead =0;
   while (offset< bytes.length
     &&(numRead = is.read(bytes, offset,

bytes.length - offset)) >= 0) {
    offset+= numRead;
   }

   if (offset< bytes.length)
    thrownew IOException("Cound not completely read

file "
      +file.getName());
   is.close();

  } catch (Exception e){
   Log.e("tag",e.getMessage());
  } finally {
   try {
    if(is != null) {
     is.close();
    }
   } catch(Exception ex) {
    Log.e("tag",ex.getMessage());
   }
  }
  return bytes;
 }