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转自:http://blog.youkuaiyun.com/billy_zuo/article/details/71077681
Android截屏
Android截屏的原理:获取具体需要截屏的区域的Bitmap,然后绘制在画布上,保存为图片后进行分享或者其它用途
一、Activity截屏
1、截Activity界面(包含空白的状态栏)
[java] view plain copy
- /**
- * 根据指定的Activity截图(带空白的状态栏)
- *
- * @param context 要截图的Activity
- * @return Bitmap
- */
- public static Bitmap shotActivity(Activity context) {
- View view = context.getWindow().getDecorView();
- view.setDrawingCacheEnabled(true);
- view.buildDrawingCache();
- Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache(), 0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
- view.setDrawingCacheEnabled(false);
- view.destroyDrawingCache();
- return bitmap;
- }
2、截Activity界面(去除状态栏)
[java] view plain copy
- /**
- * 根据指定的Activity截图(去除状态栏)
- *
- * @param activity 要截图的Activity
- * @return Bitmap
- */
- public Bitmap shotActivityNoStatusBar(Activity activity) {
- // 获取windows中最顶层的view
- View view = activity.getWindow().getDecorView();
- view.buildDrawingCache();
- // 获取状态栏高度
- Rect rect = new Rect();
- view.getWindowVisibleDisplayFrame(rect);
- int statusBarHeights = rect.top;
- Display display = activity.getWindowManager().getDefaultDisplay();
- // 获取屏幕宽和高
- int widths = display.getWidth();
- int heights = display.getHeight();
- // 允许当前窗口保存缓存信息
- view.setDrawingCacheEnabled(true);
- // 去掉状态栏
- Bitmap bmp = Bitmap.createBitmap(view.getDrawingCache(), 0,
- statusBarHeights, widths, heights - statusBarHeights);
- // 销毁缓存信息
- view.destroyDrawingCache();
- return bmp;
- }
二、View截屏
[java] view plain copy
- /**
- * 根据指定的view截图
- *
- * @param v 要截图的view
- * @return Bitmap
- */
- 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 bitmap = Bitmap.createBitmap(v.getDrawingCache(), 0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
- v.setDrawingCacheEnabled(false);
- v.destroyDrawingCache();
- return bitmap;
- }
三、ScrollView截屏:ScrollView只有一个childView,虽然没有全部显示在界面上,但是已经全部渲染绘制,因此可以直接 调用scrollView.draw(canvas)来完成截图
[java] view plain copy
- /**
- * Scrollview截屏
- *
- * @param scrollView 要截图的ScrollView
- * @return Bitmap
- */
- public static Bitmap shotScrollView(ScrollView scrollView) {
- int h = 0;
- Bitmap bitmap = null;
- for (int i = 0; i < scrollView.getChildCount(); i++) {
- h += scrollView.getChildAt(i).getHeight();
- scrollView.getChildAt(i).setBackgroundColor(Color.parseColor("#ffffff"));
- }
- bitmap = Bitmap.createBitmap(scrollView.getWidth(), h, Bitmap.Config.RGB_565);
- final Canvas canvas = new Canvas(bitmap);
- scrollView.draw(canvas);
- return bitmap;
- }
四、ListView截屏:ListView是会回收与重用Item,并且只会绘制在屏幕上显示的ItemView,下面的方法采用一个List来存储Item的视图,这种方案依然不够好,当Item足够多的时候,可能会发生oom。
[java] view plain copy
- /**
- * ListView截图
- *
- * @param listView 要截图的ListView
- * @return Bitmap
- */
- public static Bitmap shotListView(ListView listView) {
- ListAdapter adapter = listView.getAdapter();
- int itemsCount = adapter.getCount();
- int allItemsHeight = 0;
- ArrayList<Bitmap> bmps = new ArrayList<>();
- for (int i = 0; i < itemsCount; i++) {
- View childView = adapter.getView(i, null, listView);
- childView.measure(View.MeasureSpec.makeMeasureSpec(listView.getWidth(),View.MeasureSpec.EXACTLY),
- View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED));
- childView.layout(0, 0, childView.getMeasuredWidth(), childView.getMeasuredHeight());
- childView.setDrawingCacheEnabled(true);
- childView.buildDrawingCache();
- bmps.add(childView.getDrawingCache());
- allItemsHeight += childView.getMeasuredHeight();
- }
- Bitmap bigBitmap = Bitmap.createBitmap(listView.getMeasuredWidth(), allItemsHeight, Bitmap.Config.ARGB_8888);
- Canvas bigCanvas = new Canvas(bigBitmap);
- Paint paint = new Paint();
- int iHeight = 0;
- for (int i = 0; i < bmps.size(); i++) {
- Bitmap bmp = bmps.get(i);
- bigCanvas.drawBitmap(bmp, 0, iHeight, paint);
- iHeight += bmp.getHeight();
- bmp.recycle();
- bmp = null;
- }
- return bigBitmap;
- }
五、RecycleView截屏
[java] view plain copy
- /**
- * RecyclerView截屏
- *
- * @param view 要截图的RecyclerView
- * @return Bitmap
- */
- public static Bitmap shotRecyclerView(RecyclerView view) {
- RecyclerView.Adapter adapter = view.getAdapter();
- Bitmap bigBitmap = null;
- if (adapter != null) {
- int size = adapter.getItemCount();
- int height = 0;
- Paint paint = new Paint();
- int iHeight = 0;
- final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
- // Use 1/8th of the available memory for this memory cache.
- final int cacheSize = maxMemory / 8;
- LruCache<String, Bitmap> bitmaCache = new LruCache<>(cacheSize);
- for (int i = 0; i < size; i++) {
- RecyclerView.ViewHolder holder = adapter.createViewHolder(view, adapter.getItemViewType(i));
- adapter.onBindViewHolder(holder, i);
- holder.itemView.measure(
- View.MeasureSpec.makeMeasureSpec(view.getWidth(), View.MeasureSpec.EXACTLY),
- View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
- holder.itemView.layout(0, 0, holder.itemView.getMeasuredWidth(),
- holder.itemView.getMeasuredHeight());
- holder.itemView.setDrawingCacheEnabled(true);
- holder.itemView.buildDrawingCache();
- Bitmap drawingCache = holder.itemView.getDrawingCache();
- if (drawingCache != null) {
- bitmaCache.put(String.valueOf(i), drawingCache);
- }
- height += holder.itemView.getMeasuredHeight();
- }
- bigBitmap = Bitmap.createBitmap(view.getMeasuredWidth(), height, Bitmap.Config.ARGB_8888);
- Canvas bigCanvas = new Canvas(bigBitmap);
- Drawable lBackground = view.getBackground();
- if (lBackground instanceof ColorDrawable) {
- ColorDrawable lColorDrawable = (ColorDrawable) lBackground;
- int lColor = lColorDrawable.getColor();
- bigCanvas.drawColor(lColor);
- }
- for (int i = 0; i < size; i++) {
- Bitmap bitmap = bitmaCache.get(String.valueOf(i));
- bigCanvas.drawBitmap(bitmap, 0f, iHeight, paint);
- iHeight += bitmap.getHeight();
- bitmap.recycle();
- }
- }
- return bigBitmap;
- }
六、WebView截屏
1、截取webView可视区域的截图
[java] view plain copy
- /**
- * 截取webView可视区域的截图
- * @param webView 前提:WebView要设置webView.setDrawingCacheEnabled(true);
- * @return
- */
- private Bitmap captureWebViewVisibleSize(WebView webView){
- Bitmap bmp = webView.getDrawingCache();
- return bmp;
- }
2、
[java] view plain copy
- /**
- * 截取webView快照(webView加载的整个内容的大小)
- * @param webView
- * @return
- */
- private Bitmap captureWebView(WebView webView){
- Picture snapShot = webView.capturePicture();
- Bitmap bmp = Bitmap.createBitmap(snapShot.getWidth(),snapShot.getHeight(), Bitmap.Config.ARGB_8888);
- Canvas canvas = new Canvas(bmp);
- snapShot.draw(canvas);
- return bmp;
- }
3、截取
[java] view plain copy
- /**
- * 截屏
- *
- * @param context
- * @return
- */
- private Bitmap captureScreen(Activity context) {
- View cv = context.getWindow().getDecorView();
- Bitmap bmp = Bitmap.createBitmap(cv.getWidth(), cv.getHeight(), Bitmap.Config.ARGB_8888);
- Canvas canvas = new Canvas(bmp);
- cv.draw(canvas);
- return bmp;
- }