2012-01-12 89 views
8

如何从InputStream(资产,文件系统)加载drawable并基于屏幕分辨率hdpi,mdpi或ldpi动态调整其大小?Android负载以编程方式绘制并调整大小

原始图像是在hdpi中,我只需要调整大小为mdpi和ldpi。

有谁知道Android如何动态调整/ res中的drawables的大小?

+0

出于好奇,有什么理由不预上浆它(为'mdpi'和'ldpi')并在'res'目录中链接到它? – 2012-01-12 15:45:58

+0

从网络下载的图像。我可以在服务器上执行预处理,但下载速度会变慢。 – peceps 2012-01-12 15:48:42

回答

4

发现:

/** 
    * Loads image from file system. 
    * 
    * @param context the application context 
    * @param filename the filename of the image 
    * @param originalDensity the density of the image, it will be automatically 
    * resized to the device density 
    * @return image drawable or null if the image is not found or IO error occurs 
    */ 
    public static Drawable loadImageFromFilesystem(Context context, String filename, int originalDensity) { 
    Drawable drawable = null; 
    InputStream is = null; 

    // set options to resize the image 
    Options opts = new BitmapFactory.Options(); 
    opts.inDensity = originalDensity; 

    try { 
     is = context.openFileInput(filename); 
     drawable = Drawable.createFromResourceStream(context.getResources(), null, is, filename, opts);   
    } catch (Throwable e) { 
     // handle 
    } finally { 
     if (is != null) { 
     try { 
      is.close(); 
     } catch (Throwable e1) { 
      // ingore 
     } 
     } 
    } 
    return drawable; 
    } 

使用这样的:

loadImageFromFilesystem(context, filename, DisplayMetrics.DENSITY_MEDIUM); 
+1

Unfortunatley此代码不适用于HTC Desire HD和HTC Evo。在此处查看解决方案:http://stackoverflow.com/questions/7747089/exception-in-drawable-createfromresourcestream-htc-only/9195531#9195531 – peceps 2012-02-08 14:46:47

1

如果你想显示的图像,但不幸的是这个形象是大尺寸的,让例子,你要显示的图像以30乘30的格式,然后检查它的大小,如果它大于你的要求大小,然后除以你的数量(在这里是30 * 30),然后你再次拿到并用来再次分割图像区域。

drawable = this.getResources().getDrawable(R.drawable.pirImg); 
int width = drawable.getIntrinsicWidth(); 
int height = drawable.getIntrinsicHeight(); 
if (width > 30)//means if the size of an image is greater than 30*30 
{ 
    width = drawable.getIntrinsicWidth()/30; 
    height = drawable.getIntrinsicWidth()/30; 
} 

drawable.setBounds(
    0, 0, 
    drawable.getIntrinsicWidth()/width, 
    drawable.getIntrinsicHeight()/height); 

//and now add the modified image in your overlay 
overlayitem[i].setMarker(drawable) 
8

这是很好的和容易(其他的答案没有工作对我来说),发现here

ImageView iv = (ImageView) findViewById(R.id.imageView); 
    Bitmap bMap = BitmapFactory.decodeResource(getResources(), R.drawable.picture); 
    Bitmap bMapScaled = Bitmap.createScaledBitmap(bMap, newWidth, newHeight, true); 
    iv.setImageBitmap(bMapScaled); 

Android文档可here

0

后加载您的图片,并将其设置为imageview的 你可以使用layoutparamsto大小的图像match_parent

这样

android.view.ViewGroup.LayoutParams layoutParams = imageView.getLayoutParams(); 
layoutParams.width =MATCH_PARENT; 
layoutParams.height =MATCH_PARENT; 
imageView.setLayoutParams(layoutParams); 
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