android dialog背景模糊化效果實(shí)現(xiàn)方法

更新時(shí)間：2021年04月21日 09:03:17 作者：lbcab

這篇文章主要為大家詳細(xì)介紹了android dialog背景模糊化效果的實(shí)現(xiàn)方法，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

最近做項(xiàng)目有這樣的需求: 在activity中啟動(dòng)一個(gè)dialog時(shí), 啟動(dòng)的dialog的背景設(shè)為啟動(dòng)acitivity的模糊化圖片.

實(shí)現(xiàn)思路:

1. 截屏, 獲取當(dāng)前activity的界面
2. 將獲取的照片進(jìn)行模糊化
3. 將模糊化的圖片設(shè)為dialog的背景

1.截屏, 獲取當(dāng)前activity的界面

private Bitmap takeScreenShot(Activity activity) {
  View view = activity.getWindow().getDecorView();
  view.setDrawingCacheEnabled(true);
  view.buildDrawingCache();
  Bitmap b1 = view.getDrawingCache();

  // 獲取屏幕長(zhǎng)和高
  int width = activity.getResources().getDisplayMetrics().widthPixels;
  int height = activity.getResources().getDisplayMetrics().heightPixels;

  Bitmap bmp = Bitmap.createBitmap(b1, 0, 0, width, height);
  view.destroyDrawingCache();
  return bmp;
 }

這里需要注意: 默認(rèn)dialog是全屏, activity也是全屏沒(méi)有狀態(tài)欄. 如果有狀態(tài)欄需要獲取狀態(tài)欄大小, 在創(chuàng)建圖片的時(shí)候減去狀態(tài)欄大小.

2.將獲取的圖片進(jìn)行模糊化, 這里的模糊算法, 是從網(wǎng)上查到, 具體是進(jìn)行高斯模糊. 具體代碼在下面的工具類中.

3.設(shè)置模糊圖片為dialog的背景

//blurBackgroundDrawer為模糊后的背景圖片
 Window window = getWindow();
 window.setBackgroundDrawable(new BitmapDrawable(mContext.getResources(), blurBackgroundDrawer));

注意: 模糊化圖片可能會(huì)比較慢, 剛開(kāi)始測(cè)得時(shí)候在3 - 4秒之間, 解決辦法是將獲取到的屏幕進(jìn)行縮小,然后在進(jìn)行模糊, 模糊完后, 再將圖片放大.

下面是將背景模糊化效果封裝成的工具類代碼, 使用方法: 只需要將其考到工程中, 在需要模糊化效果的地方調(diào)用:
Bitmap bmp = getBlurBackgroundDrawer(activity); 即可.

public class FastBlurUtility {

 /**
  * 獲得模糊化的背景圖片
  * @param activity 獲取模糊化的背景activity
  * @return 模糊化的背景圖片
  */
 public static Bitmap getBlurBackgroundDrawer(Activity activity) {
  Bitmap bmp = takeScreenShot(activity);
  return startBlurBackground(bmp);
 }

 /**
  * 截屏
  * @param activity 截屏的activity
  * @return 截屏圖片
  */
 private static Bitmap takeScreenShot(Activity activity) {
  View view = activity.getWindow().getDecorView();
  view.setDrawingCacheEnabled(true);
  view.buildDrawingCache();
  Bitmap b1 = view.getDrawingCache();

  // 獲取屏幕長(zhǎng)和高
  int width = activity.getResources().getDisplayMetrics().widthPixels;
  int height = activity.getResources().getDisplayMetrics().heightPixels;

  Bitmap bmp = Bitmap.createBitmap(b1, 0, 0, width, height);
  view.destroyDrawingCache();
  return bmp;
 }

 private static Bitmap startBlurBackground(Bitmap bkg) {
  long startMs = System.currentTimeMillis();
  float radius = 20; //模糊程度

  Bitmap overlay = fastblur(small(bkg), (int) radius);

  Log.i("FastBlurUtility", "=====blur time:" + (System.currentTimeMillis() - startMs));
  return big(overlay);
 }

 /**
  * 放大圖片
  * @param bitmap 需要放大的圖片
  * @return 放大的圖片
  */
 private static Bitmap big(Bitmap bitmap) {
  Matrix matrix = new Matrix();
  matrix.postScale(4f, 4f);
  Bitmap resizeBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
  return resizeBmp;
 }

 /**
  * 縮小圖片
  * @param bitmap 需要縮小的圖片
  * @return 縮小的圖片
  */
 private static Bitmap small(Bitmap bitmap) {
  Matrix matrix = new Matrix();
  matrix.postScale(0.25f, 0.25f);
  Bitmap resizeBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
  return resizeBmp;
 }

 /**
  * 將圖片模糊化
  * @param sentBitmap 需要模糊的圖片
  * @param radius  模糊程度
  * @return 模糊后的圖片
  */
 private static Bitmap fastblur(Bitmap sentBitmap, int radius) {

  Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);

  if (radius < 1) {
   return (null);
  }

  int w = bitmap.getWidth();
  int h = bitmap.getHeight();

  int[] pix = new int[w * h];
  bitmap.getPixels(pix, 0, w, 0, 0, w, h);

  int wm = w - 1;
  int hm = h - 1;
  int wh = w * h;
  int div = radius + radius + 1;

  int r[] = new int[wh];
  int g[] = new int[wh];
  int b[] = new int[wh];
  int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
  int vmin[] = new int[Math.max(w, h)];

  int divsum = (div + 1) >> 1;
  divsum *= divsum;
  int dv[] = new int[256 * divsum];
  for (i = 0; i < 256 * divsum; i++) {
   dv[i] = (i / divsum);
  }

  yw = yi = 0;

  int[][] stack = new int[div][3];
  int stackpointer;
  int stackstart;
  int[] sir;
  int rbs;
  int r1 = radius + 1;
  int routsum, goutsum, boutsum;
  int rinsum, ginsum, binsum;

  for (y = 0; y < h; y++) {
   rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
   for (i = -radius; i <= radius; i++) {
    p = pix[yi + Math.min(wm, Math.max(i, 0))];
    sir = stack[i + radius];
    sir[0] = (p & 0xff0000) >> 16;
    sir[1] = (p & 0x00ff00) >> 8;
    sir[2] = (p & 0x0000ff);
    rbs = r1 - Math.abs(i);
    rsum += sir[0] * rbs;
    gsum += sir[1] * rbs;
    bsum += sir[2] * rbs;
    if (i > 0) {
     rinsum += sir[0];
     ginsum += sir[1];
     binsum += sir[2];
    } else {
     routsum += sir[0];
     goutsum += sir[1];
     boutsum += sir[2];
    }
   }
   stackpointer = radius;

   for (x = 0; x < w; x++) {

    r[yi] = dv[rsum];
    g[yi] = dv[gsum];
    b[yi] = dv[bsum];

    rsum -= routsum;
    gsum -= goutsum;
    bsum -= boutsum;

    stackstart = stackpointer - radius + div;
    sir = stack[stackstart % div];

    routsum -= sir[0];
    goutsum -= sir[1];
    boutsum -= sir[2];

    if (y == 0) {
     vmin[x] = Math.min(x + radius + 1, wm);
    }
    p = pix[yw + vmin[x]];

    sir[0] = (p & 0xff0000) >> 16;
    sir[1] = (p & 0x00ff00) >> 8;
    sir[2] = (p & 0x0000ff);

    rinsum += sir[0];
    ginsum += sir[1];
    binsum += sir[2];

    rsum += rinsum;
    gsum += ginsum;
    bsum += binsum;

    stackpointer = (stackpointer + 1) % div;
    sir = stack[(stackpointer) % div];

    routsum += sir[0];
    goutsum += sir[1];
    boutsum += sir[2];

    rinsum -= sir[0];
    ginsum -= sir[1];
    binsum -= sir[2];

    yi++;
   }
   yw += w;
  }
  for (x = 0; x < w; x++) {
   rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
   yp = -radius * w;
   for (i = -radius; i <= radius; i++) {
    yi = Math.max(0, yp) + x;

    sir = stack[i + radius];

    sir[0] = r[yi];
    sir[1] = g[yi];
    sir[2] = b[yi];

    rbs = r1 - Math.abs(i);

    rsum += r[yi] * rbs;
    gsum += g[yi] * rbs;
    bsum += b[yi] * rbs;

    if (i > 0) {
     rinsum += sir[0];
     ginsum += sir[1];
     binsum += sir[2];
    } else {
     routsum += sir[0];
     goutsum += sir[1];
     boutsum += sir[2];
    }

    if (i < hm) {
     yp += w;
    }
   }
   yi = x;
   stackpointer = radius;
   for (y = 0; y < h; y++) {
    pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];

    rsum -= routsum;
    gsum -= goutsum;
    bsum -= boutsum;

    stackstart = stackpointer - radius + div;
    sir = stack[stackstart % div];

    routsum -= sir[0];
    goutsum -= sir[1];
    boutsum -= sir[2];

    if (x == 0) {
     vmin[y] = Math.min(y + r1, hm) * w;
    }
    p = x + vmin[y];

    sir[0] = r[p];
    sir[1] = g[p];
    sir[2] = b[p];

    rinsum += sir[0];
    ginsum += sir[1];
    binsum += sir[2];

    rsum += rinsum;
    gsum += ginsum;
    bsum += binsum;

    stackpointer = (stackpointer + 1) % div;
    sir = stack[stackpointer];

    routsum += sir[0];
    goutsum += sir[1];
    boutsum += sir[2];

    rinsum -= sir[0];
    ginsum -= sir[1];
    binsum -= sir[2];

    yi += w;
   }
  }

  bitmap.setPixels(pix, 0, w, 0, 0, w, h);

  return (bitmap);
 }
}

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