Android WebView实现网页滚动截图

WebView 网页滚动截屏，可对整个网页进行截屏而不是仅当前屏幕哦！

注意若Web页面存在position:fixed; 的话得在调用前设置为 position:absolute; 哦，否则会出现很多次的，请看下面的具体解说吧！！

private static Bitmap getViewBitmapWithoutBottom(View v) {
 if (null == v) {
  return null;
 }
 v.setDrawingCacheEnabled(true);
 v.buildDrawingCache();
 if (Build.VERSION.SDK_INT >= 11) {
  v.measure(View.MeasureSpec.makeMeasureSpec(v.getWidth(), View.MeasureSpec.EXACTLY), View.MeasureSpec.makeMeasureSpec(v.getHeight(), View.MeasureSpec.EXACTLY));
  v.layout((int) v.getX(), (int) v.getY(), (int) v.getX() + v.getMeasuredWidth(), (int) v.getY() + v.getMeasuredHeight());
 } else {
  v.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED), View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
  v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
 }
 Bitmap bp = Bitmap.createBitmap(v.getDrawingCache(), 0, 0, v.getMeasuredWidth(), v.getMeasuredHeight() - v.getPaddingBottom());
 v.setDrawingCacheEnabled(false);
 v.destroyDrawingCache();
 return bp;
}

public static Bitmap getViewBitmap(View v) {
 if (null == v) {
  return null;
 }
 v.setDrawingCacheEnabled(true);
 v.buildDrawingCache();
 if (Build.VERSION.SDK_INT >= 11) {
  v.measure(View.MeasureSpec.makeMeasureSpec(v.getWidth(), View.MeasureSpec.EXACTLY), View.MeasureSpec.makeMeasureSpec(v.getHeight(), View.MeasureSpec.EXACTLY));
  v.layout((int) v.getX(), (int) v.getY(), (int) v.getX() + v.getMeasuredWidth(), (int) v.getY() + v.getMeasuredHeight());
 } else {
  v.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED), View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
  v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
 }
 Bitmap b = Bitmap.createBitmap(v.getDrawingCache(), 0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
 v.setDrawingCacheEnabled(false);
 v.destroyDrawingCache();
 return b;
}

/**
 * 获取 WebView 视图截图
 * @param context
 * @param view
 * @return
 */
public static Bitmap getWebViewBitmap(Context context, WebView view) {
 if (null == view) return null;
 view.scrollTo(0, 0);
 view.buildDrawingCache(true);
 view.setDrawingCacheEnabled(true);
 view.setVerticalScrollBarEnabled(false);
 Bitmap b = getViewBitmapWithoutBottom(view);
 // 可见高度
 int vh = view.getHeight();
 // 容器内容实际高度
 int th = (int)(view.getContentHeight()*view.getScale());
 Bitmap temp = null;
 if (th > vh) {
  int w = getScreenWidth(context);
  int absVh = vh - view.getPaddingTop() - view.getPaddingBottom();
  do {
   int restHeight = th - vh;
   if (restHeight <= absVh) {
    view.scrollBy(0, restHeight);
    vh += restHeight;
    temp = getViewBitmap(view);
   } else {
    view.scrollBy(0, absVh);
    vh += absVh;
    temp = getViewBitmapWithoutBottom(view);
   }
   b = mergeBitmap(vh, w, temp, 0, view.getScrollY(), b, 0, 0);
  } while (vh < th);
 }
 // 回滚到顶部
 view.scrollTo(0, 0);
 view.setVerticalScrollBarEnabled(true);
 view.setDrawingCacheEnabled(false);
 view.destroyDrawingCache();
 return b;
}

/**
 * 拼接图片
 * @param newImageH
 * @param newImageW
 * @param background
 * @param backX
 * @param backY
 * @param foreground
 * @param foreX
 * @param foreY
 * @return
 */
private static Bitmap mergeBitmap(int newImageH, int newImageW, Bitmap background, float backX, float backY, Bitmap foreground, float foreX, float foreY) {
 if (null == background || null == foreground) {
  return null;
 }
 Bitmap bitmap = Bitmap.createBitmap(newImageW, newImageH, Bitmap.Config.RGB_565);
 Canvas cv = new Canvas(bitmap);
 cv.drawBitmap(background, backX, backY, null);
 cv.drawBitmap(foreground, foreX, foreY, null);
 cv.save(Canvas.ALL_SAVE_FLAG);
 cv.restore();
 return bitmap;
}

/**
 * get the width of screen
 */
public static int getScreenWidth(Context ctx) {
 int w = 0;
 if (Build.VERSION.SDK_INT > 13) {
  Point p = new Point();
  ((WindowManager) ctx.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getSize(p);
  w = p.x;
 } else {
  w = ((WindowManager) ctx.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getWidth();
 }
 return w;
}

/**
 * 保存图片
 * @param context
 * @param bitmap
 * @param file
 * @param quality
 * @return
 */
public static boolean save(Context context, Bitmap bitmap, File file, int quality) {
 if (bitmap == null) return false;
 // 获得后缀格式
 String abs = file.getAbsolutePath();
 String suffix = abs.substring(abs.lastIndexOf(".")+1).toLowerCase();
 Bitmap.CompressFormat format;
 if ("jpg".equals(suffix) || "jpeg".equals(suffix)) {
  format = Bitmap.CompressFormat.JPEG;
 } else {
  format = Bitmap.CompressFormat.PNG;
  quality = 100;
 }
 if (file.exists() && ! file.delete()) return false;
 try {
  FileOutputStream stream = new FileOutputStream(file);
  bitmap.compress(format, quality, stream);
  stream.flush();
  stream.close();
  context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(file)));
  return true;
 } catch (Exception e) {
  return false;
}
}

JS调用截屏操作

/**
 * 屏幕截图
 * @param name
 * @param isRecover
*/
@JavascriptInterface
public String Capture(String name, boolean isRecover) {
 File dir = new File(Config.PUBLIC_PICTURES_PATH);
 LogUtil.i("capture", dir.getAbsolutePath());
 if (! dir.exists() && ! dir.mkdirs()) return null;
 final File file = new File(dir, name);
 String path = file.getAbsolutePath();
 if (file.exists() && ! isRecover) return path;
 body.post(new Runnable() {
  @Override
  public void run() {
   Bitmap bitmap = CaptureUtil.getWebViewBitmap(activity, body);
   if (null != bitmap) ImageUtil.save(activity, bitmap, file, 100);
  }
 });
 return path;
}
@JavascriptInterface
public String Capture(String name) {
 return Capture(name, true);
}
@JavascriptInterface
public String Capture() {
 String name = String.valueOf(System.currentTimeMillis()) + ".png";
 return Capture(name);
}

示例图：我先通过 JS 触发显示了一个原生的 Button按钮， 然后WebView跳转到 csdn 页面，然后点击截屏按钮用来触发网页截屏的。下面的图是我手动截的图，不是上面代码的效果哈，下下面很长的那张才是Java程序的网页截图。

测试CSDN的网页完整截图：比较长哦~ 一般截图的功能都用于特殊的页面，如活动页面之类的，不会太长，那样是没有问题的。若是这种滚动到底部自动加载的话可能就会很长很长很长啦·····，自己看着办吧。。

但这里有个BUG，顶部固定Banner条每次截屏都有，这个有解决办法，不过得是你自己的网页才有操作权限哦，需要修改JS啦。

当截图JS命令触发前，把顶部悬浮的样式设置为绝对定位，当截屏完成后再改回固定定位即可，没什么难度了。

截屏是需要一些时间的，所以需要预设一个定时器来操作，JS栗子如下:

JS.Capture 是 WebView 绑定的自定义 Javascript 类对象

var file = '';
var $header = $("#layout-header");
 $header.css({ position: "absolute" });
 setTimeout(function(){
  if (typeof name == "function" || typeof name == "undefined") {
   file = JS.Capture();
  } else {
   file = JS.Capture(name, isRecover);
  }
 }, 500);
 setTimeout(function(){
  JS.Toast("截图已保存", "fast");
  JS.Toast(file.replace("storage/emulated/0/", ""));
  $header.css({ position: "fixed" });
  if ($.isFunction(callback)) {
   callback(file);
  }
 }, 1500);

来源：https://blog.csdn.net/zhouzme/article/details/51804824