Drawable、Bitmap、byte[]之间的转换

 

博客分类： 
• android技术

Android 

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;
}

 

2、从资源中获取Bitmap

 

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();
   }

 
4、 byte[] → Bitmap

private Bitmap Bytes2Bimap(byte[] b){
            if(b.length!=0){
                return BitmapFactory.decodeByteArray(b, 0, b.length);
            }
            else {
                return null;
            }
      }

 

一、Bitmap转Drawable 


Bitmap bm=xxx; //xxx根据你的情况获取 

BitmapDrawable bd=new BitmapDrawable(bm); 
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。 
Drawable d=xxx; //xxx根据自己的情况获取drawable 

BitmapDrawable bd = (BitmapDrawable) d; 

Bitmap bm = bd.getBitmap(); 
最终bm就是我们需要的Bitmap对象了。 



// 从资源中获取Bitmap 
public static Bitmap getBitmapFromResources(Activity act, int resId) { 
Resources res = act.getResources(); 
return BitmapFactory.decodeResource(res, resId); 
} 

// byte[] → Bitmap 
public static Bitmap convertBytes2Bimap(byte[] b) { 
if (b.length == 0) { 
return null; 
} 
return BitmapFactory.decodeByteArray(b, 0, b.length); 
} 

// Bitmap → byte[] 
public static byte[] convertBitmap2Bytes(Bitmap bm) { 
ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
bm.compress(Bitmap.CompressFormat.PNG, 100, baos); 
return baos.toByteArray(); 
} 

// 1)Drawable → Bitmap 
public static Bitmap convertDrawable2BitmapByCanvas(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)Drawable → Bitmap 
public static Bitmap convertDrawable2BitmapSimple(Drawable drawable){ 
BitmapDrawable bd = (BitmapDrawable) drawable; 
return bd.getBitmap(); 
} 

// Bitmap → Drawable 
public static Drawable convertBitmap2Drawable(Bitmap bitmap) { 
BitmapDrawable bd = new BitmapDrawable(bitmap); 
// 因为BtimapDrawable是Drawable的子类，最终直接使用bd对象即可。 
return bd; 
}