在Android中，可以通过将图片转换为模糊效果来创建毛玻璃背景。使用
RenderScript或第三方库如Glide实现图片模糊，然后将其设置为背景即可。在Android开发中，实现图片的毛玻璃背景效果是一种常见需求，这种效果不仅可以提升应用的视觉美感，还能增强用户体验，本文将详细介绍如何在Android中实现图片毛玻璃背景效果，包括使用Java算法和RenderScript两种方法，以下是详细内容：
一、准备工作
1、添加RenderScript支持：确保你的项目已经添加了RenderScript支持，在你的build.gradle文件中，添加以下代码：
android {
defaultConfig {
renderscriptTargetApi 21
renderscriptSupportModeEnabled true
}
}二、使用Java算法FastBlur实现
1. FastBlurUtility类
我们需要创建一个工具类FastBlurUtility，用于实现模糊效果，这个工具类包含几个静态方法，用于处理图像的缩放和模糊处理。
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Matrix;
public class FastBlurUtility {
private static final float BITMAP_SCALE = 0.4f;
private static final float BLUR_RADIUS = 7.5f;
public static Bitmap getBlurBackgroundDrawer(Activity activity) {
Bitmap bmp = takeScreenShot(activity);
return startBlurBackground(bmp);
}
private static Bitmap takeScreenShot(Activity activity) {
View view = activity.getWindow().getDecorView();
view.setDrawingCacheEnabled(true);
view.buildDrawingCache();
Bitmap b1 = view.getDrawingCache();
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);
}
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;
}
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;
}
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[] stack = new int[wh];
int[] r = new int[wh];
int[] g = new int[wh];
int[] b = new int[wh];
int ri = radius + radius + 1;
int di = ri / 2;
int r_outsum, g_outsum, b_outsum;
int r_insum, g_insum, b_insum;
int sum;
int x, y, i;
for (y = 0; y < h; y++) {
for (i = -di; i <= di; i++) {
r_insum += r[y * w + Math.min(wm, Math.max(i, 0))];
g_insum += g[y * w + Math.min(wm, Math.max(i, 0))];
b_insum += b[y * w + Math.min(wm, Math.max(i, 0))];
}
for (i = -di; i <= di; i++) {
r_outsum += r[(y + 1) * w + Math.min(wm, Math.max(i, 0))];
g_outsum += g[(y + 1) * w + Math.min(wm, Math.max(i, 0))];
b_outsum += b[(y + 1) * w + Math.min(wm, Math.max(i, 0))];
}
for (x = 0; x < w; x++) {
r[yi] = dv[r[yi]];
g[yi] = dv[g[yi]];
b[yi] = dv[b[yi]];
yi++;
}
for (i = -di; i <= di; i++) {
r[yi] = r_insum;
g[yi] = g_insum;
b[yi] = b_insum;
yi++;
}
for (x = 0; x < w; x++) {
r_insum -= r[yi ri];
g_insum -= g[yi ri];
b_insum -= b[yi ri];
stack[ri] = (r[yi] << 16) | (g[yi] << 8) | b[yi];
sum = stack[ri];
stack[ri++] = sum;
r_outsum -= r[yi];
g_outsum -= g[yi];
b_outsum -= b[yi];
r_insum += r[yi];
g_insum += g[yi];
b_insum += b[yi];
r[yi] = stack[di];
g[yi] = stack[di] >> 8;
b[yi] = stack[di] >> 16;
yi++;
}
}
for (x = 0; x < w; x++) {
r_outsum += r[yi ri];
g_outsum += g[yi ri];
b[yi ri] = b_outsum;
stack[ri] = (r[yi] << 16) | (g[yi] << 8) | b[yi];
sum = stack[ri];
stack[ri++] = sum;
r_outsum -= r[yi];
g_outsum -= g[yi];
b_outsum -= b[yi];
r_insum += r[yi];
g_insum += g[yi];
b_insum += b[yi];
r[yi] = stack[di];
g[yi] = stack[di] >> 8;
b[yi] = stack[di] >> 16;
yi++;
}
for (y = 0; y < h; y++) {
for (i = -di; i <= di; i++) {
r_insum += r[y * w + Math.min(wm, Math.max(i, 0))];
g_insum += g[y * w + Math.min(wm, Math.max(i, 0))];
b_insum += b[y * w + Math.min(wm, Math.max(i, 0))];
}
for (i = -di; i <= di; i++) {
r_outsum += r[(y + 1) * w + Math.min(wm, Math.max(i, 0))];
g_outsum += g[(y + 1) * w + Math.min(wm, Math.max(i, 0))];
b_outsum += b[(y + 1) * w + Math.min(wm, Math.max(i, 0))];
}
for (x = 0; x < w; x++) {
r[yi] = dv[r[yi]];
g[yi] = dv[g[yi]];
b[yi] = dv[b[yi]];
yi++;
}
for (i = -di; i <= di; i++) {
r[yi] = r_insum;
g[yi] = g_insum;
b[yi] = b_insum;
yi++;
}
for (x = 0; x < w; x++) {
r_insum -= r[yi ri];
g_insum -= g[yi ri];
b_insum -= b[yi ri];
stack[ri] = (r[yi] << 16) | (g[yi] << 8) | b[yi];
sum = stack[ri];
stack[ri++] = sum;
r_outsum -= r[yi];
g_outsum -= g[yi];
b_outsum -= b[yi];
r_insum += r[yi];
g_insum += g[yi];
b_insum += b[yi];
r[yi] = stack[di];
g[yi] = stack[di] >> 8;
b[yi] = stack[di] >> 16;
yi++;
}
}
for (x = 0; x < w; x++) {
r_outsum += r[yi ri];
g_outsum += g[yi ri];
b[yi ri] = b_outsum;
stack[ri] = (r[yi] << 16) | (g[yi] << 8) | b[yi];
sum = stack[ri];
stack[ri++] = sum;
r_outsum -= r[yi];
g_outsum -= g[yi];
b_outsum -= b[yi];
r_insum += r[yi];
g_insum += g[yi];
b_insum += b[yi];
r[yi] = stack[di];
g[yi] = stack[di] >> 8;
b[yi] = stack[di] >> 16;
yi++;
}
return bitmap;
}
}2. 使用方法示例：
在Activity中调用上述工具类的方法，实现毛玻璃效果，假设有一个ImageView控件用于显示原图和模糊后的图片。
import android.os.Bundle; import android.util.Log;import android.widget.ImageView; import androidx.appcompat.app.AppCompatActivity; import java.lang.ref.*;WeakReference;import com.example.myapplication.*;import android.graphics.*;import android.content.*;import android.support.v8.renderscript.*;import android.view.View;import androidx.core.content.*;ContextCompat;import java.lang.*;import java.util.*;import android.graphics.*;import android.graphics.drawable.*;import android.os.Build.*;import androidx.annotation.*;NonNull;import androidx.core.content.*;ContextCompat;import androidx.appcompat.app.*;import androidx.constraintlayout.*;import androidx.constraintlayout.widget.*;import androidx.appcompat.widget.*;import androidx.recyclerview.*;import androidx.recyclerview.widget.*;import androidx.viewpager.widget.*;import androidx.viewpager2.widget.*;import androidx.fragment.app.*;import androidx.lifecycle.*;import androidx.lifecycle.ViewModel;import androidx.lifecycle.Observer;import androidx.localbroadcastmanager.*;import androidx.multidex.*;import androidx.*;import androidx.annotation.*;Nullable;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;Nullable;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.*;import androidx.annotation.*;NonNull;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import androidx.*;import 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