Android毛玻璃效果

通常实现android毛玻璃效果，根据api等级有两种实现的方式：

1.api大于16的

2.api小于等于16的

   在公司项目中用到毛玻璃效果，因为要适配4.0一下的机型，所以只能用第二中，只看了第二种怎么实现。

下面展示一个实例：

 有两个activity ，一个MyActivity.java， 一个MainActivity

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;

public class MyActivity extends Activity implements OnClickListener{
	
	public static MyActivity instance = null;  
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.test);
		findViewById(R.id.btn1).setOnClickListener(this);
		instance = this;
	}
	
	@Override
	public void onClick(View v) {
		if(v.getId() == R.id.btn1){
			Intent intent = new Intent(this, MainActivity.class);
			startActivity(intent);
		}
	}
}

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends Activity {

	private ImageView mImageView;
	private LinearLayout layout;
	private int mWidth;
	private int mHeight;
	private TextView textView;
	private Button btn1;
	private int statusBarHeight;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		layout = (LinearLayout) findViewById(R.id.ll);

		DisplayMetrics metrics = new DisplayMetrics();
		this.getWindowManager().getDefaultDisplay().getMetrics(metrics);
		mWidth = metrics.widthPixels;
		mHeight = metrics.heightPixels;
		Rect frame = new Rect();
		MyActivity.instance.getWindow().getDecorView()
				.getWindowVisibleDisplayFrame(frame);
		statusBarHeight = frame.top;
		blur1(layout);
	}

	private void blur1(final LinearLayout ll) {
		int radius = 10;
		float scaleFactor = 8;

		View view = MyActivity.instance.getWindow().getDecorView();
		view.setDrawingCacheEnabled(true);
		Bitmap mBitmap = view.getDrawingCache();

		if (mBitmap == null) {
			return;
		}
		int width = mBitmap.getWidth();
		int height = mBitmap.getHeight();

		Bitmap overlay = Bitmap.createBitmap((int) (width / scaleFactor),
				(int) (height / scaleFactor), Bitmap.Config.ARGB_8888); //对上一个activity的截图进行处理，要不然加载会很慢
		Canvas canvas = new Canvas(overlay);
		canvas.scale(1 / scaleFactor, 1 / scaleFactor);
		Paint paint = new Paint();
		paint.setFlags(Paint.FILTER_BITMAP_FLAG);
		canvas.drawBitmap(mBitmap, 0, 0, paint);
		view.setDrawingCacheEnabled(false);
		final Bitmap blurBitmap = FastBlur.fastblur(this, overlay, radius);
		ll.post(new Runnable() {
			@Override
			public void run() {
				ll.setBackgroundDrawable(new BitmapDrawable(blurBitmap));
			}
		});
	}
}

下面是xml文件：activity_main.xml 和 test.xml 

test.xml 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidtest12.MainActivity" >

    <Button
        android:id="@+id/btn1"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:text="11111111" />

</RelativeLayout>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/ll"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#d9101016"
    android:orientation="vertical" >

</FrameLayout>

还有一个实现毛玻璃效果的文件FastBlur.java

import android.content.Context;
import android.graphics.Bitmap;

public class FastBlur {
public static Bitmap fastblur(Context context, 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];
//        Log.e("pix", w + " " + h + " " + pix.length);
        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 temp = 256 * divsum;
        int dv[] = new int[temp];
        for (i = 0; i < temp; 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++) {
                // Preserve alpha channel: ( 0xff000000 & pix[yi] )
                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;
            }
        }

//        Log.e("pix", w + " " + h + " " + pix.length);
        bitmap.setPixels(pix, 0, w, 0, 0, w, h);
        return (bitmap);
    }
}