安卓：生成视图的位图无图纸 [英] Android: Generate bitmap of a view without drawing

问题描述

我们必须产生从特定视图的位图的问题。的限制是，它不能被呈现的视图（图）。有没有人有任何提示如何解决此问题？

类视图的文档（ http://developer.android.com /reference/android/view/View.html ）具有用于由Android渲染视图的步骤一些解释。在这种情况下，我们会在步骤得到布局，而不是引的。任何人谁有任何想法，可以显示一个例子吗？

我的code正在生成异常：
错误 - >宽度和高度必须> 0

  ...
公共静态位图loadBitmapFromView（视图v）{
    位图B = NULL;
    尝试{
        B = Bitmap.createBitmap（
                v.getWidth（），
                v.getHeight（），
                Bitmap.Config.ARGB_8888）;
        帆布C =新的Canvas（B）;
        v.measure（v.getWidth（），v.getHeight（））;
        v.layout（0，0，v.getWidth（），v.getHeight（））;
        v.draw（C）;    }赶上（例外五）{        Log.e（MainActivity.TAG，错误 - ＆gt;中+ e.getMessage（））;
    }    返回b;
}
公共无效卡（视图v）{
    LayoutInflater膨胀=（LayoutInflater）getBaseContext（）
            .getSystemService（LAYOUT_INFLATER_SERVICE）;
    查看查看=新景（getBaseContext（））;
    鉴于= inflate.inflate（R.layout.list_item，NULL）;
    Log.d（MainActivity.TAG的getWidth  - ＆gt;中+ view.getWidth（））;
    Log.d（MainActivity.TAG的getHeight  - ＆gt;中+ view.getHeight（））;    位图B = loadBitmapFromView（视图）;
    如果（B！= NULL）{        的LinearLayout mainLayout =（的LinearLayout）findViewById（R.id.LinearLayout1）;
        ImageView的形象=新ImageView的（本）;
        image.setImageBitmap（二）;        mainLayout.addView（图片）;
    }
}
 

解决方案

我找到了解决办法是这样的：

 公共静态位图getScreenViewBitmap（最终查看V）{
    v.setDrawingCacheEnabled（真）;    v.measure（MeasureSpec.makeMeasureSpec（0，MeasureSpec.UNSPECIFIED），
            MeasureSpec.makeMeasureSpec（0，MeasureSpec.UNSPECIFIED））;
    v.layout（0，0，v.getMeasuredWidth（），v.getMeasuredHeight（））;    v.buildDrawingCache（真）;
    位图B = Bitmap.createBitmap（v.getDrawingCache（））;
    v.setDrawingCacheEnabled（假）; //明确绘图缓存    返回b;
}
 

We have a problem to generate a bitmap from a particular view. The restriction is that it can not be rendered view (drawing). Does anyone have any tips how to solve this?

The documentation of the class view (http://developer.android.com/reference/android/view/View.html) has some explanation of the steps used by Android to render a View. In the case, we would get in step "layout", but not in the "drawing". Anyone who has any idea, could show an example?

My code is generating the exception: error -> width and height must be> 0

...
public static Bitmap loadBitmapFromView(View v) {
    Bitmap b = null;
    try {
        b = Bitmap.createBitmap(
                v.getWidth(),
                v.getHeight(), 
                Bitmap.Config.ARGB_8888);                
        Canvas c = new Canvas(b);
        v.measure(v.getWidth(), v.getHeight()); 
        v.layout(0, 0, v.getWidth(), v.getHeight());
        v.draw(c);

    } catch (Exception e) {

        Log.e(MainActivity.TAG, "error -> "+e.getMessage());
    }



    return b;
}


public void snap(View v) {


    LayoutInflater inflate = (LayoutInflater) getBaseContext()
            .getSystemService(LAYOUT_INFLATER_SERVICE);
    View view = new View(getBaseContext());
    view = inflate.inflate(R.layout.list_item, null);


    Log.d(MainActivity.TAG, "getWidth -> "+view.getWidth());
    Log.d(MainActivity.TAG, "getHeight   -> "+view.getHeight());

    Bitmap b = loadBitmapFromView(view);
    if (b != null) {

        LinearLayout mainLayout = (LinearLayout) findViewById(R.id.LinearLayout1);
        ImageView image = new ImageView(this);
        image.setImageBitmap(b);

        mainLayout.addView(image);
    }


}

解决方案

I found the solution this way:

public static Bitmap getScreenViewBitmap(final View v) {
    v.setDrawingCacheEnabled(true);

    v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());

    v.buildDrawingCache(true);
    Bitmap b = Bitmap.createBitmap(v.getDrawingCache());
    v.setDrawingCacheEnabled(false); // clear drawing cache

    return b;
}

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