cannot seem to get bitmap from view in android

cannot seem to get bitmap from view in android - android

My problem is similar to the one in Android View.getDrawingCache returns null, only null.
My code used to work with the method
private Bitmap getBitmapFromView(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;
}
But today I changed the xml layout file. Since the change I have been getting NullPointerException at the line Bitmap b = Bitmap.createBitmap(v.getDrawingCache()). So I tried changing the method getBitmapFromView to
public static Bitmap loadBitmapFromView(View v) {
Bitmap b = Bitmap.createBitmap(v.getLayoutParams().width, v.getLayoutParams().height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.layout(0, 0, v.getLayoutParams().width, v.getLayoutParams().height);
v.draw(c);
return b;
}
But that didn't help. I get the null in the very first line.
The situation is this: I am trying to convert the view into a bitmap. But I am doing this without first displaying the view on screen. Again, this all used to work until I changed the content of the xml layout file. The change was not even that big. I just moved stuff around and removed -- yes removed -- some of the subviews.
In any case, I know for certain there is no problem with my layout file because I can display it on screen if I want; which I have done as part of troubleshooting.
Someone suggested using a handler to call getDrawingCache(). If that's the answer, how would I write that code?
UPDATE
View view = activity.getLayoutInflater().inflate(R.layout.my_view, null, false);
findViewsByIds(view);//where I inflate subviews and add content to them.

Execute createBitmapFromView when the view is measured.
public static void executeWhenViewMeasured(final View view, final Runnable runnable) {
if(view.getMeasuredHeight() == 0 || view.getMeasuredWidth() == 0){
view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
runnable.run();
removeGlobalOnLayoutListener(view, this);
}
});
} else {
runnable.run();
}
}
public static Bitmap createBitmapFromView(View view) {
Bitmap bitmap = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
view.draw(canvas);
return bitmap;
}
#TargetApi(Build.VERSION_CODES.JELLY_BEAN)
public static void removeGlobalOnLayoutListener(View view,
ViewTreeObserver.OnGlobalLayoutListener listener) {
try {
view.getViewTreeObserver().removeOnGlobalLayoutListener(listener);
} catch (NoSuchMethodError e) {
view.getViewTreeObserver().removeGlobalOnLayoutListener(listener);
}
}
executeWhenViewMeasured(view, new Runnable() {
#Override
public void run() {
Bitmap bitmap = createBitmapFromView(view);
}
});

Since you are not showing the view it's easier to just draw the view on a canvas.
You are already trying to do that but I would merge both methods into one without using drawing cache.
private Bitmap getBitmapFromView(View v) {
v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredWidth());
Bitmap b = Bitmap.createBitmap(v.getMeasuredWidth(), v.getMeasuredWidth(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.draw(c);
return b;
}
Also check that MeasureSpec.UNSPECIFIED may not work well without the view in layout so you may need to specify a width and height.

Related

Converting a view to Bitmap without displaying (with setHorizontallyScrollyng) in Android?

In my code, I have a LinearLayout with many TextViews (like a table). And I try to convert this to Bitmap. there is my code:
public static Bitmap convertToBitmap(LinearLayout view){
view.measure(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
Bitmap bitmap = Bitmap.createBitmap(view.getWidth(),
view.getHeight(),
Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bitmap);
view.draw(c);
return bitmap;
}
But, there is a problem.
Views witch has setSingleLine(true) not display text in bitmap.
Exactly, the problem is in setHorizontallyScrolling(true), which is calling in setSingleLine code...
I try use .setScrollTo(X), but what exactly X must be. X = 0 - not works.
Is there any, who knows how fix it?
EDIT: TextViews has fixed Width.
EDIT: Problem is only for TextViews with Gravity = Center. With gravity Left all's ok.

Try one of this code? It's a bit different from the one you posted above.
/**
* this actually also provided by Romain Guy, but let's try another for performance improvements
*/
public static Bitmap getBitmapFromView(View view, int width, int height) {
view.measure(View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY));
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
// Build the Drawing Cache
view.buildDrawingCache();
// Create Bitmap
Bitmap drawingCache = view.getDrawingCache();
if (drawingCache == null) {
return null;
}
Bitmap bitmap = Bitmap.createBitmap(drawingCache);
drawingCache.recycle();
view.setDrawingCacheEnabled(false);
return bitmap;
}
/**
* This method provided by Romain Guy, so it should do the job better, especially it includes case for listViews
*/
public static Bitmap getBitmapFromView(View view, int width, int height) {
//Pre-measure the view so that height and width don't remain null.
view.measure(View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY), View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY));
//Assign a size and position to the view and all of its descendants
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
// Create bitmap
Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.RGB_565);
//Create a canvas with the specified bitmap to draw into
Canvas canvas = new Canvas(bitmap);
// if it's scrollView we get gull size
canvas.translate(-view.getScrollX(), -view.getScrollY());
//Render this view (and all of its children) to the given Canvas
view.draw(canvas);
return bitmap;
}

Convert ExpandableListview to bitmap

I am unable to get bitmap of expandable listview
This is what I tried
private Bitmap convertViewToBitMap() {
View printlayout = (View) getActivity().findViewById(R.id.expandableList);
printlayout.setDrawingCacheEnabled(true);
printlayout.measure(
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
printlayout.layout(0, 0, printlayout.getMeasuredWidth(),
printlayout.getMeasuredHeight());
printlayout.buildDrawingCache(true);
Bitmap b = Bitmap.createBitmap(printlayout.getDrawingCache());
printlayout.setDrawingCacheEnabled(false); // clear drawing cache
return b;
}

Following method helped me
private Bitmap convertViewToBitMap() {
View printlayout = (View) getActivity().findViewById(R.id.expandableList);
printlayout.setDrawingCacheEnabled(true);
Bitmap b = printlayout.getDrawingCache();
return b;
}

I think all you need it to get the hold of the view and convert that view into the bitmap and then print the bitmap.
You can get the view using findViewById();
For converting view into bitmap, a quick google may help more, but i found this
And once you have bitmap, do what ever you want.
#Pietu1998 pointed correctly, also show your attempt so reduce chance for downvoting.

You can re-draw your list into a bitmap which you can then use.
Here I'm issuing a re-draw on an instance variable mListView and then using that bitmap for my ImageView. Note that I'm using a Handler to force the re-draw on the UI thread.
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
Bitmap bitmap = Bitmap.createBitmap(mListView.getWidth(),
mListView.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
mListView.draw(canvas);
// Do something the
((ImageView)mContext.findViewById(R.id.img)).setImageBitmap(bitmap);
}
}, 1);
Also note that you will need to have the ImageView inside of your xml already and the ListView not taking up all the space in the layout.

Android: Generate bitmap of a view without drawing

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);
}
}

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;
}

You're immediately trying to get the width and height of the view after inflation, but the View doesn't have a size until after it's been laid out. You can either determine a size for it yourself (call measure() with whatever MeasureSpec is appropriate) or have it as part of a layout, set to Invisible, and only try to load the Bitmap from the View after it has been laid out.

Getting screenshot from a LinearLayout

I have a LinearLayout that contains a lot of sub LinearLayouts which contain TextViews. I want to get a screenshot from the parent LinearLayout to get a full view of my "Receipt". So I tried to do that:
View v = findViewById(R.id.llReceipt);
v.setDrawingCacheEnabled(true);
Bitmap b = v.getDrawingCache();
the problem is the Bitmap b get a null value.
Is there any solution to solve it?

I don't know why your bitmap is null but I've used this bit before to get a screen shot of a custom view and it worked:
public Bitmap getBitmapFromView(View view, int width, int height) {
Bitmap returnedBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(returnedBitmap);
Drawable bgDrawable = view.getBackground();
if (view==mainPage.boardView) {
canvas.drawColor(BoardView.BOARD_BG_COLOR);
} else if (bgDrawable!=null) {
bgDrawable.draw(canvas);
} else {
canvas.drawColor(Color.WHITE);
}
view.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));
view.layout(0, 0, width, height);
view.draw(canvas);
return returnedBitmap;
}
Taken from here!

I found my problem:
I called the getScreenShot() Function from the onCreate() Function which doesn't work.
it should call it after this step.

Converting a view to Bitmap without displaying it in Android?

I will try to explain what exactly I need to do.
I have 3 separate screens say A,B,C. There is another screen called say HomeScreen where all the 3 screens bitmap should be displayed in Gallery view and the user can select in which view does he wants to go.
I have been able to get the Bitmaps of all the 3 screens and display it in Gallery view by placing all the code in HomeScreen Activity only. Now, this has complicated the code a lot and I will like to simplify it.
So, can I call another Activity from HomeScreen and do not display it and just get the Bitmap of that screen. For example, say I just call HomeScreen and it calls Activity A,B,C and none of the Activities from A,B,C are displayed. It just gives the Bitmap of that screen by getDrawingCache(). And then we can display those bitmaps in Gallery view in HomeScreen.
I hope I have explained the problem very clearly.
Please let me know if this is actually possible.

there is a way to do this. you have to create a Bitmap and a Canvas and call view.draw(canvas);
here is the code:
public static Bitmap loadBitmapFromView(View v) {
Bitmap b = Bitmap.createBitmap( v.getLayoutParams().width, v.getLayoutParams().height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.layout(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());
v.draw(c);
return b;
}
if the view wasn't displayed before the size of it will be zero. Its possible to measure it like this:
if (v.getMeasuredHeight() <= 0) {
v.measure(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
Bitmap b = Bitmap.createBitmap(v.getMeasuredWidth(), v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
v.draw(c);
return b;
}
EDIT: according to this post, Passing WRAP_CONTENT as value to makeMeasureSpec() doesn't to do any good (although for some view classes it does work), and the recommended method is:
// Either this
int specWidth = MeasureSpec.makeMeasureSpec(parentWidth, MeasureSpec.AT_MOST);
// Or this
int specWidth = MeasureSpec.makeMeasureSpec(0 /* any */, MeasureSpec.UNSPECIFIED);
view.measure(specWidth, specWidth);
int questionWidth = view.getMeasuredWidth();

here is my solution:
public static Bitmap getBitmapFromView(View view) {
Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(returnedBitmap);
Drawable bgDrawable =view.getBackground();
if (bgDrawable!=null)
bgDrawable.draw(canvas);
else
canvas.drawColor(Color.WHITE);
view.draw(canvas);
return returnedBitmap;
}
Enjoy :)

I know this may be a stale issue, but I was having problems getting any of these solutions to work for me.
Specifically, I found that if any changes were made to the view after it was inflated that those changes would not get incorporated into the rendered bitmap.
Here's the method which ended up working for my case. With one caveat, however. prior to calling getViewBitmap(View) I inflated my view and asked it to layout with known dimensions. This was needed since my view layout would make it zero height/width until content was placed inside.
View view = LayoutInflater.from(context).inflate(layoutID, null);
//Do some stuff to the view, like add an ImageView, etc.
view.layout(0, 0, width, height);
Bitmap getViewBitmap(View view)
{
//Get the dimensions of the view so we can re-layout the view at its current size
//and create a bitmap of the same size
int width = view.getWidth();
int height = view.getHeight();
int measuredWidth = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
int measuredHeight = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY);
//Cause the view to re-layout
view.measure(measuredWidth, measuredHeight);
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
//Create a bitmap backed Canvas to draw the view into
Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
//Now that the view is laid out and we have a canvas, ask the view to draw itself into the canvas
view.draw(c);
return b;
}
The "magic sauce" for me was found here:
https://groups.google.com/forum/#!topic/android-developers/BxIBAOeTA1Q
Cheers,
Levi

Try this,
/**
* Draw the view into a bitmap.
*/
public static Bitmap getViewBitmap(View v) {
v.clearFocus();
v.setPressed(false);
boolean willNotCache = v.willNotCacheDrawing();
v.setWillNotCacheDrawing(false);
// Reset the drawing cache background color to fully transparent
// for the duration of this operation
int color = v.getDrawingCacheBackgroundColor();
v.setDrawingCacheBackgroundColor(0);
if (color != 0) {
v.destroyDrawingCache();
}
v.buildDrawingCache();
Bitmap cacheBitmap = v.getDrawingCache();
if (cacheBitmap == null) {
Log.e(TAG, "failed getViewBitmap(" + v + ")", new RuntimeException());
return null;
}
Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);
// Restore the view
v.destroyDrawingCache();
v.setWillNotCacheDrawing(willNotCache);
v.setDrawingCacheBackgroundColor(color);
return bitmap;
}

There is a great Kotlin extension function in Android KTX: View.drawToBitmap(Bitmap.Config)

Layout or view to bitmap:
private Bitmap createBitmapFromLayout(View tv) {
int spec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
tv.measure(spec, spec);
tv.layout(0, 0, tv.getMeasuredWidth(), tv.getMeasuredHeight());
Bitmap b = Bitmap.createBitmap(tv.getMeasuredWidth(), tv.getMeasuredWidth(),
Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
c.translate((-tv.getScrollX()), (-tv.getScrollY()));
tv.draw(c);
return b;
}
Calling Method:
Bitmap src = createBitmapFromLayout(View.inflate(this, R.layout.sample, null)/* or pass your view object*/);

I think this is a bit better :
/**
* draws the view's content to a bitmap. code initially based on :
* http://nadavfima.com/android-snippet-inflate-a-layout-draw-to-a-bitmap/
*/
#Nullable
public static Bitmap drawToBitmap(final View viewToDrawFrom, int width, int height) {
boolean wasDrawingCacheEnabled = viewToDrawFrom.isDrawingCacheEnabled();
if (!wasDrawingCacheEnabled)
viewToDrawFrom.setDrawingCacheEnabled(true);
if (width <= 0 || height <= 0) {
if (viewToDrawFrom.getWidth() <= 0 || viewToDrawFrom.getHeight() <= 0) {
viewToDrawFrom.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
width = viewToDrawFrom.getMeasuredWidth();
height = viewToDrawFrom.getMeasuredHeight();
}
if (width <= 0 || height <= 0) {
final Bitmap bmp = viewToDrawFrom.getDrawingCache();
final Bitmap result = bmp == null ? null : Bitmap.createBitmap(bmp);
if (!wasDrawingCacheEnabled)
viewToDrawFrom.setDrawingCacheEnabled(false);
return result;
}
viewToDrawFrom.layout(0, 0, width, height);
} else {
viewToDrawFrom.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));
viewToDrawFrom.layout(0, 0, viewToDrawFrom.getMeasuredWidth(), viewToDrawFrom.getMeasuredHeight());
}
final Bitmap drawingCache = viewToDrawFrom.getDrawingCache();
final Bitmap bmp = ThumbnailUtils.extractThumbnail(drawingCache, width, height);
final Bitmap result = bmp == null || bmp != drawingCache ? bmp : Bitmap.createBitmap(bmp);
if (!wasDrawingCacheEnabled)
viewToDrawFrom.setDrawingCacheEnabled(false);
return result;
}
Using the above code, you don't have to specify the size of the bitmap (use 0 for width&height) if you want to use the one of the view itself.
Also, if you wish to convert special views (SurfaceView, Surface or Window, for example) to a bitmap, you should consider using PixelCopy class instead. It requires API 24 and above though. I don't know how to do it before.

Hope this helps
View view="some view instance";
view.setDrawingCacheEnabled(true);
Bitmap bitmap=view.getDrawingCache();
view.setDrawingCacheEnabled(false);
Update
getDrawingCache() method is deprecated in API level 28. So look for other alternative for API level > 28.

I used this just a few days ago:
fun generateBitmapFromView(view: View): Bitmap {
val specWidth = View.MeasureSpec.makeMeasureSpec(1324, View.MeasureSpec.AT_MOST)
val specHeight = View.MeasureSpec.makeMeasureSpec(521, View.MeasureSpec.AT_MOST)
view.measure(specWidth, specHeight)
val width = view.measuredWidth
val height = view.measuredHeight
val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
val canvas = Canvas(bitmap)
view.layout(view.left, view.top, view.right, view.bottom)
view.draw(canvas)
return bitmap
}
This code is based in this gist

I had a similar need and developed something based on codes provided, specially the one by #Azhagthott and the brand new androidx.core.view.drawToBitmap, hopefully this will be hopeful here also,
val view = MyCustomView(context)
view.measure(
View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.AT_MOST),
View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.AT_MOST)
)
view.layout(0, 0, width, height)
val bitmap = view.drawToBitmap()

private fun getBitmapFromView(view: View): Bitmap
{
val returnedBitmap = Bitmap.createBitmap(view.width,
view.height
,Bitmap.Config.ARGB_8888)
val canvas = Canvas(returnedBitmap)
//background image
val bgDrawable = view.background
//background image is selected
if (bgDrawable != null){
bgDrawable.draw(canvas)
}
else{
canvas.drawColor(Color.WHITE)
}
view.draw(canvas)
return returnedBitmap
}

I had the same problem in my project and found a solution, which I will describe here.
public Bitmap catchBitmapFromView(View capture_view){
if (capture_view == null) {
return null;
}
capture_view.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(capture_view.getWidth(), capture_view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Drawable bgDrawable = capture_view.getBackground();
if (bgDrawable != null) {
bgDrawable.draw(canvas);
} else {
canvas.drawColor(Color.WHITE);
}
capture_view.draw(canvas);
capture_view.setDrawingCacheEnabled(false);
return bitmap;
}

view.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache());
view.setDrawingCacheEnabled(false);

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

cannot seem to get bitmap from view in android - android

Related

Converting a view to Bitmap without displaying (with setHorizontallyScrollyng) in Android?

Convert ExpandableListview to bitmap

Android: Generate bitmap of a view without drawing

Getting screenshot from a LinearLayout

Converting a view to Bitmap without displaying it in Android?

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