Android截屏截图的几种方法总结

　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）

/**
   * 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）

/**
   * 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

/**
 * 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

/**
 * 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。

/**
 * 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

/**
   * 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

/**
  * 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、截取webView的整个页面

/**
 * 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、截取手机屏幕，获取界面展示的webview

/**
 * 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;
}

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