全Java代码实现Launcher3抽屉模式高斯模糊

以下是一个全 Java 代码实现 Launcher3 抽屉模式高斯模糊的示例，仅供参考：

1. 创建 RenderScript 脚本文件 GaussianBlur.rs：

#pragma version(1)
#pragma rs java_package_name(com.example.launcher3)

rs_allocation inputAllocation;
rs_allocation outputAllocation;

int width;
int height;
int radius;

void root(const uchar4 *v_in, uchar4 *v_out, const void *usrData, uint32_t x, uint32_t y) {
    float4 sum = 0;
    float wsum = 0;
    int r = radius;

    for (int i = -r; i <= r; i++) {
        for (int j = -r; j <= r; j++) {
            if ((x + i) >= 0 && (x + i) < width && (y + j) >= 0 && (y + j) < height) {
                float4 color = rsUnpackColor8888(*(rsGetElementAt_uchar4(inputAllocation, x + i, y + j)));
                float weight = exp(-(i * i + j * j) / (2.0f * r * r));
                sum += color * weight;
                wsum += weight;
            }
        }
    }

    *v_out = rsPackColorTo8888(sum / wsum);
}

2. Java 代码实现：

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.drawable.BitmapDrawable;
import android.support.v4.widget.DrawerLayout;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.RelativeLayout;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

import androidx.renderscript.Allocation;
import androidx.renderscript.Element;
import androidx.renderscript.RenderScript;
import androidx.renderscript.ScriptC;

public class DrawerBlurHelper implements AdapterView.OnItemClickListener, DrawerLayout.DrawerListener {
    private Context mContext;
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private RelativeLayout mDrawerBackground;

    private RenderScript mRenderScript;
    private ScriptC_GaussianBlur mScriptGaussianBlur;

    public DrawerBlurHelper(Context context, DrawerLayout drawerLayout, ListView drawerList, RelativeLayout drawerBackground) {
        mContext = context;
        mDrawerLayout = drawerLayout;
        mDrawerList = drawerList;
        mDrawerBackground = drawerBackground;

        initRenderScript();
        mDrawerList.setOnItemClickListener(this);
        mDrawerLayout.addDrawerListener(this);
    }

    private void initRenderScript() {
        mRenderScript = RenderScript.create(mContext);
        mScriptGaussianBlur = new ScriptC_GaussianBlur(mRenderScript, readScriptFromResource(R.raw.gaussianblur));
    }

    private byte[] readScriptFromResource(int resourceId) {
        try {
            InputStream inputStream = mContext.getResources().openRawResource(resourceId);
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int length;
            while ((length = inputStream.read(buffer)) != -1) {
                byteArrayOutputStream.write(buffer, 0, length);
            }
            return byteArrayOutputStream.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    private Bitmap getDrawerBitmap() {
        int width = mDrawerList.getWidth();
        int height = mDrawerList.getHeight();
        Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        mDrawerList.draw(canvas);
        return bitmap;
    }

    private Bitmap blurBitmap(Bitmap inputBitmap, int radius) {
        int width = inputBitmap.getWidth();
        int height = inputBitmap.getHeight();
        Bitmap outputBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Allocation inputAllocation = Allocation.createFromBitmap(mRenderScript, inputBitmap);
        Allocation outputAllocation = Allocation.createFromBitmap(mRenderScript, outputBitmap);
        mScriptGaussianBlur.set_inputAllocation(inputAllocation);
        mScriptGaussianBlur.set_outputAllocation(outputAllocation);
        mScriptGaussianBlur.set_width(width);
        mScriptGaussianBlur.set_height(height);
        mScriptGaussianBlur.set_radius(radius);
        mScriptGaussianBlur.invoke_filter();
        outputAllocation.copyTo(outputBitmap);
        return outputBitmap;
    }

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        mDrawerLayout.closeDrawer(mDrawerList);
    }

    @Override
    public void onDrawerSlide(View drawerView, float slideOffset) {
        if (slideOffset > 0) {
            Bitmap drawerBitmap = getDrawerBitmap();
            Bitmap blurredBitmap = blurBitmap(drawerBitmap, 10);
            mDrawerBackground.setBackground(new BitmapDrawable(mContext.getResources(), blurredBitmap));
        }
    }

    @Override
    public void onDrawerOpened(View drawerView) {
        Bitmap drawerBitmap = getDrawerBitmap();
        Bitmap blurredBitmap = blurBitmap(drawerBitmap, 10);
        mDrawerBackground.setBackground(new BitmapDrawable(mContext.getResources(), blurredBitmap));
    }

    @Override
    public void onDrawerClosed(View drawerView) {
        mDrawerBackground.setBackground(null);
    }

    @Override
    public void onDrawerStateChanged(int newState) {
        // do nothing
    }
}

以上是一个全 Java 代码实现的示例，实际实现中可能需要根据具体情况进行修改和优化。