Android WebView实现网页滚动截图
作者：袖梨
2022-06-25
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);
