android.webkit.WebView#draw ( )源码实例Demo

private Bitmap captureWebView3(WebView wv) {
    try {
        float scale = wv.getScale();
        int height = (int) (wv.getContentHeight() * scale + 0.5);
        Bitmap bitmap = Bitmap.createBitmap(wv.getWidth(), height, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        wv.draw(canvas);
        return bitmap;
    } catch (Exception e) {
        try {
            openCache(wv);
            return wv.getDrawingCache();
        } finally {
            closeCache(wv);
        }
    }
}
 

/**
 * Convert view to an image.  Can be used to make animations smoother.
 *
 * @param context           The current Context or Activity that this method is called from
 * @param viewToBeConverted View to convert to a Bitmap
 * @return Bitmap object that can be put in an ImageView.  Will look like the converted viewToBeConverted.
 */
public static Bitmap viewToImage(Context context, WebView viewToBeConverted) {
    int extraSpace = 2000; //because getContentHeight doesn't always return the full screen height.
    int height = viewToBeConverted.getContentHeight() + extraSpace;

    Bitmap viewBitmap = Bitmap.createBitmap(viewToBeConverted.getWidth(), height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(viewBitmap);
    viewToBeConverted.draw(canvas);

    //If the view is scrolled, cut off the top part that is off the screen.
    try {
        int scrollY = viewToBeConverted.getScrollY();
        if (scrollY > 0) {
            viewBitmap = Bitmap.createBitmap(viewBitmap, 0, scrollY, viewToBeConverted.getWidth(), height - scrollY);
        }
    } catch (Exception ex) {
        Log.e("PercolateAndroidUtils", "Could not remove top part of the webview image.  ex=" + ex);
    }

    return viewBitmap;
}
 

/**
 * Convert view to an image.  Can be used to make animations smoother.
 *
 * @param context           The current Context or Activity that this method is called from
 * @param viewToBeConverted View to convert to a Bitmap
 * @return Bitmap object that can be put in an ImageView.  Will look like the converted viewToBeConverted.
 */
public static Bitmap viewToImage(Context context, WebView viewToBeConverted) {
    int extraSpace = 2000; //because getContentHeight doesn't always return the full screen height.
    int height = viewToBeConverted.getContentHeight() + extraSpace;

    Bitmap viewBitmap = Bitmap.createBitmap(viewToBeConverted.getWidth(), height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(viewBitmap);
    viewToBeConverted.draw(canvas);

    //If the view is scrolled, cut off the top part that is off the screen.
    try {
        int scrollY = viewToBeConverted.getScrollY();
        if (scrollY > 0) {
            viewBitmap = Bitmap.createBitmap(viewBitmap, 0, scrollY, viewToBeConverted.getWidth(), height - scrollY);
        }
    } catch (Exception ex) {
        Log.e("PercolateAndroidUtils", "Could not remove top part of the webview image.  ex=" + ex);
    }

    return viewBitmap;
}
 

/**
 * Convert view to an image.  Can be used to make animations smoother.
 *
 * @param context           The current Context or Activity that this method is called from.
 * @param viewToBeConverted View to convert to a Bitmap.
 * @return Bitmap object that can be put in an ImageView.  Will look like the converted viewToBeConverted.
 */
public static Bitmap viewToImage(Context context, WebView viewToBeConverted) {
    int extraSpace = 2000; //because getContentHeight doesn't always return the full screen height.
    int height = viewToBeConverted.getContentHeight() + extraSpace;

    Bitmap viewBitmap = Bitmap.createBitmap(viewToBeConverted.getWidth(), height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(viewBitmap);
    viewToBeConverted.draw(canvas);

    //If the view is scrolled, cut off the top part that is off the screen.
    try {
        int scrollY = viewToBeConverted.getScrollY();
        if (scrollY > 0) {
            viewBitmap = Bitmap.createBitmap(viewBitmap, 0, scrollY, viewToBeConverted.getWidth(), height - scrollY);
        }
    } catch (Exception ex) {
        Log.e("Caffeine", "Could not remove top part of the webview image.  ex=" + ex);
    }

    return viewBitmap;
}
 

@SuppressLint("WrongCall")
private Bitmap captureWebView2(@NonNull final WebView view) {
    openCache(view);
    int measureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    view.measure(measureSpec, measureSpec);
    if (view.getMeasuredWidth() <= 0 || view.getMeasuredHeight() <= 0) {
        return null;
    }
    Bitmap bm;
    try {
        bm = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    } catch (OutOfMemoryError e) {
        System.gc();
        try {
            bm = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.RGB_565);
        } catch (OutOfMemoryError ee) {
            closeCache(view);
            return captureWebView3(view);
        }
    }
    Canvas bigCanvas = new Canvas(bm);
    Paint paint = new Paint();
    int iHeight = bm.getHeight();
    bigCanvas.drawBitmap(bm, 0, iHeight, paint);
    view.draw(bigCanvas);
    closeCache(view);
    return bm;
}
 

private static void createType2(WebView webView, FileHelper.OnSavedToGalleryListener listener) {
    float scale = webView.getScale();
    int webViewHeight = (int) (webView.getContentHeight() * scale + 0.5);
    Bitmap bitmap = Bitmap.createBitmap(webView.getWidth(), webViewHeight, Config.RGB_565);
    Canvas canvas = new Canvas(bitmap);
    webView.draw(canvas);
    try {
        FileHelper.saveImageToGallery(PalmApp.getContext(), bitmap, true, listener);
        bitmap.recycle();
    } catch (Exception e) {
        LogUtils.e(e.getMessage());
    }
}
 

/**
 * Create a picture out of {@link WebView}'s whole content
 *
 * @param webView The WebView to get contents from
 * @return A {@link Bitmap} or null
 */
@Nullable
public static Bitmap getBitmapFromWebView(final WebView webView) {
    try {
        //Measure WebView's content
        int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
        webView.measure(widthMeasureSpec, heightMeasureSpec);
        webView.layout(0, 0, webView.getMeasuredWidth(), webView.getMeasuredHeight());

        //Build drawing cache and store its size
        webView.buildDrawingCache();
        int measuredWidth = webView.getMeasuredWidth();
        int measuredHeight = webView.getMeasuredHeight();

        //Creates the bitmap and draw WebView's content on in
        Bitmap bitmap = Bitmap.createBitmap(measuredWidth, measuredHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawBitmap(bitmap, 0, bitmap.getHeight(), new Paint());

        webView.draw(canvas);
        webView.destroyDrawingCache();

        return bitmap;
    } catch (Exception | OutOfMemoryError e) {
        e.printStackTrace();
        return null;
    }
}
 

/**
 * Create a picture out of {@link WebView}'s whole content
 *
 * @param webView The WebView to get contents from
 * @return A {@link Bitmap} or null
 */
@Nullable
public static Bitmap getBitmapFromWebView(final WebView webView) {
    try {
        //Measure WebView's content
        int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
        webView.measure(widthMeasureSpec, heightMeasureSpec);
        webView.layout(0, 0, webView.getMeasuredWidth(), webView.getMeasuredHeight());

        //Build drawing cache and store its size
        webView.buildDrawingCache();
        int measuredWidth = webView.getMeasuredWidth();
        int measuredHeight = webView.getMeasuredHeight();

        //Creates the bitmap and draw WebView's content on in
        Bitmap bitmap = Bitmap.createBitmap(measuredWidth, measuredHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawBitmap(bitmap, 0, bitmap.getHeight(), new Paint());

        webView.draw(canvas);
        webView.destroyDrawingCache();

        return bitmap;
    } catch (Exception | OutOfMemoryError e) {
        e.printStackTrace();
        return null;
    }
}
 

/**
 * Create a picture out of {@link WebView}'s whole content
 *
 * @param webView The WebView to get contents from
 * @return A {@link Bitmap} or null
 */
@Nullable
public static Bitmap getBitmapFromWebView(WebView webView) {
    try {
        //Measure WebView's content
        int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
        webView.measure(widthMeasureSpec, heightMeasureSpec);
        webView.layout(0, 0, webView.getMeasuredWidth(), webView.getMeasuredHeight());

        //Build drawing cache and store its size
        webView.buildDrawingCache();
        int measuredWidth = webView.getMeasuredWidth();
        int measuredHeight = webView.getMeasuredHeight();

        //Creates the bitmap and draw WebView's content on in
        Bitmap bitmap = Bitmap.createBitmap(measuredWidth, measuredHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawBitmap(bitmap, 0, bitmap.getHeight(), new Paint());

        webView.draw(canvas);
        webView.destroyDrawingCache();

        return bitmap;
    } catch (Exception | OutOfMemoryError e) {
        e.printStackTrace();
        return null;
    }
}