从android中的byteArray创建位图

问题描述

我想从bytearray创建一个位图。

我试过下面的代码

  Bitmap bmp; 
 
 bmp = BitmapFactory.decodeByteArray（data，0，data.length）; 
  

和

  ByteArrayInputStream bytes = new ByteArrayInputStream（data）; 
 BitmapDrawable bmd = new BitmapDrawable（bytes）; 
 bmp = bmd.getBitmap（）; 
  

但是，当我使用像

$ b这样的位图初始化Canvas对象
$ b

 画布canvas = new Canvas（bmp）; 
  

这会导致错误

  java.lang.IllegalStateException：传递给Canvas构造函数的不可变位图
  

如何从byteArray获取可变位图。

提前感谢。

解决方案>

您需要一个可变的位图才能创建 Canvas 。

 位图bmp = BitmapFactory.decodeByteArray（data，0，data.length）; 
 Bitmap mutableBitmap = bmp.copy（Bitmap.Config.ARGB_8888，true）; 
 Canvas canvas = new Canvas（mutableBitmap）; //现在应该可以正常工作了
  

编辑：正如Noah Seidman所说，

  BitmapFactory.Options options = new BitmapFactory.Options（）; 
 options.inMutable = true; 
 Bitmap bmp = BitmapFactory.decodeByteArray（data，0，data.length，options）; 
 Canvas canvas = new Canvas（bmp）; //现在应该工作确定
  

I want to create a bitmap from a bytearray .

I tried the following codes

Bitmap bmp;

bmp = BitmapFactory.decodeByteArray(data, 0, data.length);

and

ByteArrayInputStream bytes = new ByteArrayInputStream(data);
BitmapDrawable bmd = new BitmapDrawable(bytes);
bmp = bmd.getBitmap();

But ,When i am tring to initialize the Canvas object with the bitmap like

Canvas canvas = new Canvas(bmp);

It leads to an error

java.lang.IllegalStateException: Immutable bitmap passed to Canvas constructor

Then how to get a mutable bitmap from an byteArray.

Thanks in advance.

解决方案

You need a mutable Bitmap in order to create the Canvas.

Bitmap bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
Bitmap mutableBitmap = bmp.copy(Bitmap.Config.ARGB_8888, true);
Canvas canvas = new Canvas(mutableBitmap); // now it should work ok

Edit: As Noah Seidman said, you can do it without creating a copy.

BitmapFactory.Options options = new BitmapFactory.Options();
options.inMutable = true;
Bitmap bmp = BitmapFactory.decodeByteArray(data, 0, data.length, options);
Canvas canvas = new Canvas(bmp); // now it should work ok

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