view.getDrawingCache() returns null only in Samsung Galaxy note 8.0?

**Note : (For Nerds) Don't mark it as a duplicate question.

Yes I know what's a NullPointerException is.

yes I have tried view.getDrawingCache returns null answers from Stackoverflow.

I am trying to develop a drawing application for tablets alone. I have created a custom view which is used for drawing. The custom view is included inside an ScrollView to make the user scroll image if it's too large.

activity_drawing.xml

 <RelativeLayout
            android:id="@+id/container"
            android:layout_marginLeft="@dimen/activity_correction_answer_horizontal_margin"
            android:layout_marginRight="@dimen/activity_correction_answer_horizontal_margin"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <in.com.hourglass.views.ImageScroll   
                android:layout_centerInParent="true"
                android:id="@+id/image_scroll"
                android:layout_width="match_parent"
                android:layout_height="match_parent">

                <FrameLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content">

                    <ImageView
                        android:id="@+id/image"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content" />

                    <in.com.hourglass.views.DrawView
                        android:id="@+id/draw_view"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content" />
                </FrameLayout>
            </in.com.hourglass.views.ImageScroll>
  </RelativeLayout> 

so when the drawing over the view was done, the user can save the image and thinks drawn on Canvas .

I am resizing the image and attach it to custom view as Bitmap and save them as a single image. This whole process works fine Samsung Tablet 10.1.

But when I tried testing the same in lower screen device samsung Note 8.0 . view.getDrawingCache() is giving me a null Bitmap .

I have debugged and checked the width and height of the customview, scrollview they have specified width and height, and there is a bitmap present in customview as well.

I reuse Bitmap whenever possible to reduce app heap memory usage.

I know, i have to do something with this warning :

W/View: View too large to fit into drawing cache, needs 4380332 bytes, only 4096000 available

Error Log:

E/AndroidRuntime: FATAL EXCEPTION: main
Process: in.com.hourglassPID: 10456
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.Bitmap.getWidth()' on a null object reference
at android.graphics.Bitmap.createBitmap(Bitmap.java:614)
at in.com.hourglass.views.DrawView.getCorrectedBitmapWithoutResizing(DrawView.java:449)
at in.com.hourglass.activities.DrawingActivity.saveAnswerSheet(DrawingActivity.java:842)
at in.com.hourglass.activities.DrawingActivity.navigateNext(DrawingActivity.java:426)
at in.com.hourglass.activities.DrawingActivity.access$500(DrawingActivity.java:89)
at in.com.hourglass.activities.DrawingActivity$ToolIconClick.onClick(DrawingActivity.java:362)
at android.view.View.performClick(View.java:4789)
at android.view.View$PerformClick.run(View.java:19881)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5294)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

Code Used to get Resized Bitmap

       public class DrawView extends View {

        public void setBitmap(Bitmap bitmap) {
            this.bitmap = bitmap;
            invalidate();
        }
  @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);
        setMeasuredDimension(width, height);
    }




          public Bitmap getResizedBitmap(int originial_width, int original_height) {
                this.setDrawingCacheEnabled(true);
                Bitmap bitmap = Bitmap.createBitmap(this.getDrawingCache());
                 return  Bitmap.createScaledBitmap(bitmap,originial_width_answersheet,original_height_answersheet,false);
            }
        }

Links I have referred and unsuccessful,

Android View.getDrawingCache returns null, only null

Call to getDrawingCache returns null when scroll is enabled

etc..

---

As per your explanation, it seems like large images are not draw by the code, so for that please use below code it it is work,

I have not tested yet but I think this will help you

   public static Bitmap loadLargeBitmapFromView(View v) 
   {
      Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.ARGB_8888);

      Canvas c = new Canvas(b);
      v.layout(0, 0, v.getLayoutParams().width, v.getLayoutParams().height);
      v.draw(c);
      return b;
   } 

Edit your method as below

     public Bitmap getResizedBitmap(int originial_width, int original_height) {
                this.setDrawingCacheEnabled(true);
     Bitmap bitmap = null;
    if(this.getDrawingCache()==null)
        {
      bitmap = loadLargeBitmapFromView(this);
     }
    else
    {
     bitmap = Bitmap.createBitmap(this.getDrawingCache());
       }

   return  Bitmap.createScaledBitmap(bitmap,originial_width_answersheet,original_height_answersheet,false);
            }

链接地址: http://www.djcxy.com/p/67632.html

上一篇: 将膨胀的布局转换为位图android

下一篇: view.getDrawingCache（）仅在Samsung Galaxy note 8.0中返回null？