Android截屏方案实现原理解析

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

在截屏功能中，有时需要截取全屏的内容，有时需要截取超过一屏的内容（比如：Listview，Scrollview，RecyclerView）。下面介绍各种场景获取Bitmap的方法

普通截屏的实现

获取当前Window的DrawingCache的方式，即decorView的DrawingCache

/**
  * shot the current screen ,with the status but the status is trans *
  *
  * @param ctx current activity
  */
 public static Bitmap shotActivity(Activity ctx) {
  View view = ctx.getWindow().getDecorView();
  view.setDrawingCacheEnabled(true);
  view.buildDrawingCache();
  Bitmap bp = Bitmap.createBitmap(view.getDrawingCache(), 0, 0, view.getMeasuredWidth(),
    view.getMeasuredHeight());
  view.setDrawingCacheEnabled(false);
  view.destroyDrawingCache();
  return bp;
 }

获取当前View的DrawingCache

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

开源方案

在滚动视图中，如果当前View并没有在视图中全部绘制出来，我们可以利用View的ScrollTo()和ScrollBy()方法来移动画布，同时获取当前View的可视部分的DrawingCache，最后进行拼接得到其Bitmap，参考: PGSSoft/scrollscreenshot@[Github] 。

Scrollview截屏

三个截屏中，ScrollView最简单，因为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

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;
 }

Scrollview截屏

而ListView就是会回收与重用Item，并且只会绘制在屏幕上显示的ItemView，根据stackoverflow上大神的建议，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。

public static Bitmap shotListView(ListView listview) {
  ListAdapter adapter = listview.getAdapter();
  int itemscount = adapter.getCount();
  int allitemsheight = 0;
  List<Bitmap> bmps = new ArrayList<Bitmap>();
  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;
 }

RecyclerView截屏

我们都知道，在新的Android版本中，已经可以用RecyclerView来代替使用ListView的场景，相比较ListView，RecyclerView对Item View的缓存支持的更好。可以采用和ListView相同的方案，这里也是在stackoverflow上看到的方案。

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;
 }

上面的方法在截取存在异步加载图片的RecyclerView时候会出现加载不出图片的情况,这里再补充一种滚动式截屏的方法

public static void screenShotRecycleView(final RecyclerView mRecyclerView, final
 RecycleViewRecCallback callBack) {
    if (mRecyclerView == null) {
      return;
    }
    BaseListFragment.MyAdapter adapter = (BaseListFragment.MyAdapter) mRecyclerView.getAdapter();
    final Paint paint = new Paint();
    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);
    final int oneScreenHeight = mRecyclerView.getMeasuredHeight();
    int shotHeight = 0;
    if (adapter != null && adapter.getData().size() > 0) {
      int headerSize = adapter.getHeaderLayoutCount();
      int dataSize = adapter.getData().size();
      for (int i = 0; i < headerSize + dataSize; i++) {
        BaseViewHolder holder = (BaseViewHolder) adapter.createViewHolder(mRecyclerView, adapter.getItemViewType(i));
        if (i >= headerSize)
          adapter.startConvert(holder, adapter.getData().get(i - headerSize));
        holder.itemView.measure(
            View.MeasureSpec.makeMeasureSpec(mRecyclerView.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();
        //holder.itemView.destroyDrawingCache();//释放缓存占用的资源
        if (drawingCache != null) {
          bitmaCache.put(String.valueOf(i), drawingCache);
        }
        shotHeight += holder.itemView.getHeight();
        if (shotHeight > 12000) {
          //设置截图最大值
          if (callBack != null)
            callBack.onRecFinished(null);
          return;
        }
      }
      //添加底部高度(加载更多或loading布局高度,此处为固定值:)
      final int footHight = Util.dip2px(mRecyclerView.getContext(), 42);
      shotHeight += footHight;
      //返回到顶部
      while (mRecyclerView.canScrollVertically(-1)) {
        mRecyclerView.scrollBy(0, -oneScreenHeight);
      }
      //绘制截图的背景
      final Bitmap bigBitmap = Bitmap.createBitmap(mRecyclerView.getMeasuredWidth(), shotHeight, Bitmap.Config.ARGB_8888);
      final Canvas bigCanvas = new Canvas(bigBitmap);
      Drawable lBackground = mRecyclerView.getBackground();
      if (lBackground instanceof ColorDrawable) {
        ColorDrawable lColorDrawable = (ColorDrawable) lBackground;
        int lColor = lColorDrawable.getColor();
        bigCanvas.drawColor(lColor);
      }
      final int[] drawOffset = {0};
      final Canvas canvas = new Canvas();
      if (shotHeight <= oneScreenHeight) {
        //仅有一页
        Bitmap bitmap = Bitmap.createBitmap(mRecyclerView.getWidth(), mRecyclerView.getHeight(), Bitmap.Config.ARGB_8888);
        canvas.setBitmap(bitmap);
        mRecyclerView.draw(canvas);
        if (callBack != null)
          callBack.onRecFinished(bitmap);
      } else {
        //超过一页
        final int finalShotHeight = shotHeight;
        mRecyclerView.postDelayed(new Runnable() {
          @Override
          public void run() {
            if ((drawOffset[0] + oneScreenHeight < finalShotHeight)) {
              //超过一屏
              Bitmap bitmap = Bitmap.createBitmap(mRecyclerView.getWidth(), mRecyclerView.getHeight(), Bitmap.Config.ARGB_8888);
              canvas.setBitmap(bitmap);
              mRecyclerView.draw(canvas);
              bigCanvas.drawBitmap(bitmap, 0, drawOffset[0], paint);
              drawOffset[0] += oneScreenHeight;
              mRecyclerView.scrollBy(0, oneScreenHeight);
              try {
                bitmap.recycle();
              } catch (Exception ex) {
                ex.printStackTrace();
              }
              mRecyclerView.postDelayed(this, 10);
            } else {
              //不足一屏时的处理
              int leftHeight = finalShotHeight - drawOffset[0] - footHight;
              mRecyclerView.scrollBy(0, leftHeight);
              int top = oneScreenHeight - (finalShotHeight - drawOffset[0]);
              if (top > 0 && leftHeight > 0) {
                Bitmap bitmap = Bitmap.createBitmap(mRecyclerView.getWidth(), mRecyclerView.getHeight(), Bitmap.Config.ARGB_8888);
                canvas.setBitmap(bitmap);
                mRecyclerView.draw(canvas);
                //截图,只要补足的那块图
                bitmap = Bitmap.createBitmap(bitmap, 0, top, bitmap.getWidth(), leftHeight, null, false);
                bigCanvas.drawBitmap(bitmap, 0, drawOffset[0], paint);
                try {
                  bitmap.recycle();
                } catch (Exception ex) {
                  ex.printStackTrace();
                }
              }
              if (callBack != null)
                callBack.onRecFinished(bigBitmap);
            }
          }
        }, 10);
      }
    }
  }
  public interface RecycleViewRecCallback {
    void onRecFinished(Bitmap bitmap);
  }

相信有不少小伙伴用BRVH第三方库来做recycleview的适配器的。使用这个库的话再用上面的方法会报角标越界的错误，看了BRVH的源码

public void onBindViewHolder(ViewHolder holder, int positions) {
    int viewType = holder.getItemViewType();
    switch(viewType) {
    case 0:
      this.convert((BaseViewHolder)holder, this.mData.get(holder.getLayoutPosition() - this.getHeaderLayoutCount()));
    case 273:
    case 819:
    case 1365:
      break;
    case 546:
      this.addLoadMore(holder);
      break;
    default:
      this.convert((BaseViewHolder)holder, this.mData.get(holder.getLayoutPosition() - this.getHeaderLayoutCount()));
      this.onBindDefViewHolder((BaseViewHolder)holder, this.mData.get(holder.getLayoutPosition() - this.getHeaderLayoutCount()));
    }
  }

在调用 adapter.onBindViewHolder 时，因为里面的 position 参数未使用，里面用的计算 holder.getLayoutPosition() - this.getHeaderLayoutCount() 的值一直是-1导致角标越界报错。

本人理解，RecyclerView的截屏原理是，首先构造每个item的ViewHolder，然后调用具体设置数据到每个item的方法，此时cache中就存有item的内容，此时绘制就能获取到完整的内容。采用v7包中的 onBindViewHolder 方法即可，或者是BRVH的 convert 方法，可以看到BRVH中没有暴露出这个方法，而且唯一暴露出的 onBindViewHolder 还会报角标越界错误，此时我们就需要在BRVH的基础上暴露出 convert 即可，代码如下

public class MyAdapter extends BaseQuickAdapter<T> {
    public MyAdapter() {
      super(getItemLayoutResId(), datas);
    }
    /**
     * 用于对外暴露convert方法,构造缓存视图(截屏用)
     * @param viewHolder
     * @param t
     */
    public void startConvert(BaseViewHolder viewHolder, T t){
      convert(viewHolder,t);
    }
    @Override
    protected void convert(BaseViewHolder viewHolder, T t) {
      bindView(viewHolder, t);
    }
  }

然后将上面所述的获取Bitmap方法修改一下

/**
   * 截取recycler view
   */
  public static Bitmap getRecyclerViewScreenshot(RecyclerView view) {
    BaseListFragment.MyAdapter adapter = (BaseListFragment.MyAdapter) view.getAdapter();
    Bitmap bigBitmap = null;
    if (adapter != null) {
      int size = adapter.getData().size();
      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++) {
        BaseViewHolder holder = (BaseViewHolder) adapter.createViewHolder(view, adapter.getItemViewType(i));
        //此处需要调用convert方法，否则绘制出来的都是空的item
        adapter.startConvert(holder, adapter.getData().get(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;
  }

合成Bitmap

比如四张合成一张

/**
   * 将四张图拼成一张
   *
   * @param pic1 图一
   * @param pic2 图二
   * @param pic3 图三
   * @param pic4 图四
   * @return only_bitmap
   * 详情见说明：{@link com.bertadata.qxb.util.ScreenShotUtils}
   */
  public static Bitmap combineBitmapsIntoOnlyOne(Bitmap pic1, Bitmap pic2, Bitmap pic3, Bitmap pic4, Activity context) {
    int w_total = pic2.getWidth();
    int h_total = pic1.getHeight() + pic2.getHeight() + pic3.getHeight() + pic4.getHeight();
    int h_pic1 = pic1.getHeight();
    int h_pic4 = pic4.getHeight();
    int h_pic12 = pic1.getHeight() + pic2.getHeight();
    //此处为防止OOM需要对高度做限制
    if (h_total > HEIGHTLIMIT) {
      return null;
    }
    Bitmap only_bitmap = Bitmap.createBitmap(w_total, h_total, Bitmap.Config.ARGB_4444);
    Canvas canvas = new Canvas(only_bitmap);
    canvas.drawColor(ContextCompat.getColor(context, R.color.color_content_bg));
    canvas.drawBitmap(pic1, 0, 0, null);
    canvas.drawBitmap(pic2, 0, h_pic1, null);
    canvas.drawBitmap(pic3, 0, h_pic12, null);
    canvas.drawBitmap(pic4, 0, h_total - h_pic4, null);
    return only_bitmap;
  }

图片后期处理

/**
   * 将传入的Bitmap合理压缩后输出到系统截屏目录下
   * 命名格式为：Screenshot+时间戳+启信宝报名.jpg
   * 同时通知系统重新扫描系统文件
   *
   * @param pic1  图一 标题栏截图
   * @param pic2  图二 scrollview截图
   * @param context 用于通知重新扫描文件系统，为提升性能可去掉
   *        详情见说明：{@link com.bertadata.qxb.util.ScreenShotUtils}
   */
  public static void savingBitmapIntoFile(final Bitmap pic1, final Bitmap pic2, final Activity context, final BitmapAndFileCallBack callBack) {
    if (context == null || context.isFinishing()) {
      return;
    }
    Thread thread = new Thread(new Runnable() {
      @Override
      public void run() {
        String fileReturnPath = "";
        int w = pic1.getWidth();
        Bitmap bottom = BitmapFactory.decodeResource(context.getResources(), R.drawable.ic_picture_combine_bottom);
        Bitmap top_banner = BitmapFactory.decodeResource(context.getResources(), R.drawable.ic_picture_combine_top);
        Bitmap bitmap_bottom = anyRatioCompressing(bottom, (float) w / bottom.getWidth(), (float) w / bottom.getWidth());
        Bitmap bitmap_top = anyRatioCompressing(top_banner, (float) w / bottom.getWidth(), (float) w / bottom.getWidth());
        final Bitmap only_bitmap = combineBitmapsIntoOnlyOne(bitmap_top, pic1, pic2, bitmap_bottom, context);
        // 获取当前时间
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss-ms", Locale.getDefault());
        String data = sdf.format(new Date());
        // 获取内存路径
        // 设置图片路径+命名规范
        // 声明输出文件
        String storagePath = Environment.getExternalStorageDirectory().getAbsolutePath();
        String fileTitle = "Screenshot_" + data + "_com.bertadata.qxb.biz_info.jpg";
        String filePath = storagePath + "/DCIM/";
        final String fileAbsolutePath = filePath + fileTitle;
        File file = new File(fileAbsolutePath);
        /**
         * 质压与比压结合
         * 分级压缩
         * 输出文件
         */
        if (only_bitmap != null) {
          try {
            // 首先，对原图进行一步质量压缩,形成初步文件
            FileOutputStream fos = new FileOutputStream(file);
            only_bitmap.compress(Bitmap.CompressFormat.JPEG, 50, fos);
            // 另建一个文件other_file预备输出
            String other_fileTitle = "Screenshot_" + data + "_com.bertadata.qxb.jpg";
            String other_fileAbsolutePath = filePath + other_fileTitle;
            File other_file = new File(other_fileAbsolutePath);
            FileOutputStream other_fos = new FileOutputStream(other_file);
            // 其次，要判断质压之后的文件大小，按文件大小分级进行处理
            long file_size = file.length() / 1024; // size of file(KB)
            if (file_size < 0 || !(file.exists())) {
              // 零级： 文件判空
              throw new NullPointerException();
            } else if (file_size > 0 && file_size <= 256) {
              // 一级： 直接输出
              deleteFile(other_file);
              // 通知刷新文件系统，显示最新截取的图文件
              fileReturnPath = fileAbsolutePath;
              context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + fileAbsolutePath)));
            } else if (file_size > 256 && file_size <= 768) {
              // 二级： 简单压缩:压缩为原比例的3/4，质压为50%
              anyRatioCompressing(only_bitmap, (float) 3 / 4, (float) 3 / 4).compress(Bitmap.CompressFormat.JPEG, 40, other_fos);
              deleteFile(file);
              // 通知刷新文件系统，显示最新截取的图文件
              fileReturnPath = other_fileAbsolutePath;
              context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + other_fileAbsolutePath)));
            } else if (file_size > 768 && file_size <= 1280) {
              // 三级： 中度压缩：压缩为原比例的1/2，质压为40%
              anyRatioCompressing(only_bitmap, (float) 1 / 2, (float) 1 / 2).compress(Bitmap.CompressFormat.JPEG, 40, other_fos);
              deleteFile(file);
              // 通知刷新文件系统，显示最新截取的图文件
              fileReturnPath = other_fileAbsolutePath;
              context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + other_fileAbsolutePath)));
            } else if (file_size > 1280 && file_size <= 2048) {
              // 四级： 大幅压缩：压缩为原比例的1/3，质压为40%
              anyRatioCompressing(only_bitmap, (float) 1 / 3, (float) 1 / 3).compress(Bitmap.CompressFormat.JPEG, 40, other_fos);
              deleteFile(file);
              // 通知刷新文件系统，显示最新截取的图文件
              fileReturnPath = other_fileAbsolutePath;
              context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + other_fileAbsolutePath)));
            } else if (file_size > 2048) {
              // 五级： 中度压缩：压缩为原比例的1/2，质压为40%
              anyRatioCompressing(only_bitmap, (float) 1 / 2, (float) 1 / 2).compress(Bitmap.CompressFormat.JPEG, 40, other_fos);
              deleteFile(file);
              // 通知刷新文件系统，显示最新截取的图文件
              fileReturnPath = other_fileAbsolutePath;
              context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + other_fileAbsolutePath)));
            }
            // 注销fos;
            fos.flush();
            other_fos.flush();
            other_fos.close();
            fos.close();
            //callback用于回传保存成功的路径以及Bitmap
            callBack.onSuccess(only_bitmap, fileReturnPath);
          } catch (Exception e) {
            e.printStackTrace();
          }
        } else callBack.onSuccess(null, "");
      }
    });
    thread.start();
  }
/**
   * 可实现任意宽高比例压缩（宽高压比可不同）的压缩方法（主要用于微压）
   *
   * @param bitmap    源图
   * @param width_ratio 宽压比（float）（0<&&<1)
   * @param height_ratio 高压比（float）（0<&&<1)
   * @return 目标图片
   * <p>
   */
  public static Bitmap anyRatioCompressing(Bitmap bitmap, float width_ratio, float height_ratio) {
    Matrix matrix = new Matrix();
    matrix.postScale(width_ratio, height_ratio);
    return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);
  }

总结

以上所述是小编给大家介绍的Android截屏方案实现原理解析，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对我们网站的支持！

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