Bitmap和Drawable相互转换方法!!!

很多开发者表示，不知道 Android的 Drawable和 Bitmap之间如何相关 转换。下面Android123给大家两种比较简单高效的方法。

一、Bitmap转Drawable

1.   Bitmap bm=xxx; //xxx根据你的情况获取
   
2.   BitmapDrawable bd=BitmapDrawable(bm);
   

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Android开发网提示因为BtimapDrawable是Drawable的子类，最终直接使用bd对象即可。

二、 Drawable转Bitmap

转成Bitmap对象后，可以将Drawable对象通过Android的SK库存成一个字节输出流，最终还可以保存成为jpg和png的文件。

1. Drawable d=xxx; //xxx根据自己的情况获取drawable
   
2. BitmapDrawable bd = (BitmapDrawable) d;
   
3. Bitmap bm = bd.getBitmap();
   

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最终bm就是我们需要的Bitmap对象了。

R资源图片转bitmap:

Bitmap bmp=BitmapFactory.decodeResource(r, R.drawable.icon);
Bitmap newb = Bitmap.createBitmap( 300, 300, Config.ARGB_8888 ); 
Canvas canvasTemp = new Canvas( newb );  
 canvasTemp.drawBitmap(bmp, 50, 50, p);

1.  Bitmap 转化为 byte
ByteArrayOutputStream out = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
byte[] array= out.toByteArray(); 

2. byte转化为bitmap
final ContentResolver contentResolver = context.getContentResolver();
final PackageManager manager = context.getPackageManager();
final Cursor c = contentResolver.query(uri, null, null, null, null);
final int icon3DIndex = c.getColumnIndexOrThrow(ColumnName);
byte[] data = c.getBlob(icon3DIndex);
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);

3. bitmap转化为Drawable
Drawable drawable = new FastBitmapDrawable(bitmap);
...
4. Drawable转化为bitmap
 a. BitmapDrawable, FastBitmapDrawable直接用getBitmap
 b. 其他类型的Drawable用Canvas画到一个bitmap上
      Canvas canvas = new Canvas(bitmap)
      drawable.draw(canvas)



  
  
  
  

   
   
   
   
 
    
 
     
android在处理一写图片资源的时候，会进行一些类型的转换，现在有空整理一下： 
 
     
1、Drawable → Bitmap
 
     
 
 
     
public   static  Bitmap drawableToBitmap(Drawable drawable) {                        Bitmap bitmap = Bitmap                            .createBitmap(                                            drawable.getIntrinsicWidth(),                                            drawable.getIntrinsicHeight(),                                            drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888                                                            : Bitmap.Config.RGB_565);            Canvas canvas =  new  Canvas(bitmap);             //canvas.setBitmap(bitmap);            drawable.setBounds( 0 ,  0 , drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());            drawable.draw(canvas);             return  bitmap;    }   public static Bitmap drawableToBitmap(Drawable drawable) {                 Bitmap bitmap = Bitmap                         .createBitmap(                                         drawable.getIntrinsicWidth(),                                         drawable.getIntrinsicHeight(),                                         drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888                                                         : Bitmap.Config.RGB_565);         Canvas canvas = new Canvas(bitmap);         //canvas.setBitmap(bitmap);         drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());         drawable.draw(canvas);         return bitmap; }
 
     
2、从资源中获取Bitmap
 
     
Resources res=getResources();       Bitmap bmp=BitmapFactory.decodeResource(res, R.drawable.pic);   Resources res=getResources();
 
     
Bitmap bmp=BitmapFactory.decodeResource(res, R.drawable.pic);3、Bitmap → byte[]
 
     
private   byte [] Bitmap2Bytes(Bitmap bm){        ByteArrayOutputStream baos =  new  ByteArrayOutputStream();          bm.compress(Bitmap.CompressFormat.PNG,  100 , baos);           return  baos.toByteArray();       }   private byte[] Bitmap2Bytes(Bitmap bm){     ByteArrayOutputStream baos = new ByteArrayOutputStream();      bm.compress(Bitmap.CompressFormat.PNG, 100, baos);      return baos.toByteArray();    } 4、 byte[] → Bitmap 
 
     
 
 
     
private  Bitmap Bytes2Bimap( byte [] b){                 if (b.length!= 0 ){                     return  BitmapFactory.decodeByteArray(b,  0 , b.length);                }                 else  {                     return   null ;                }          }