仿一个美团的效果

最近在技术群里面看到有人发了一个很炫酷的效果gif图，然后再问实现的方法，看了一下效果然后自己写了一个小demo

先上人家的原图效果：

下面上我模仿的gif图，效果没有全部模仿完，界面很粗糙，只模仿效果

如下是实现代码：

package com.test.mteffect;import android.annotation.TargetApi;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.drawable.BitmapDrawable;import android.os.Build;import android.os.Bundle;import android.support.v8.renderscript.Allocation;import android.support.v8.renderscript.RenderScript;import android.support.v8.renderscript.ScriptIntrinsicBlur;import android.view.LayoutInflater;import android.view.View;import android.view.ViewTreeObserver;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.view.animation.Animation;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.ListView;import android.view.animation.Transformation;import android.view.animation.Animation.AnimationListener;import android.widget.LinearLayout.LayoutParams;public class MainActivity extends Activity {private View bg_ll_flur;private View bg_ll_bg;private ImageView mt_flur_btnimg;private LinearLayout mt_flur_ll;private ListView mt_flur_lvm;private ListView mt_flur_lv;private static int HEADHEIGHT = 0;private boolean expandable = false;private MtAdapter adapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);bg_ll_flur = this.findViewById(R.id.bg_ll_flur);bg_ll_bg = this.findViewById(R.id.bg_ll_bg);mt_flur_btnimg = (ImageView) this.findViewById(R.id.mt_flur_btnimg);mt_flur_ll = (LinearLayout) this.findViewById(R.id.mt_flur_ll);mt_flur_lvm = (ListView) this.findViewById(R.id.mt_flur_lvm);mt_flur_lv = (ListView) this.findViewById(R.id.mt_flur_lv);initView();}private void initView() {mt_flur_lvm.setAdapter(new LMtAdapter());adapter = new MtAdapter();mt_flur_lv.setAdapter(adapter);mt_flur_btnimg.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {if (expandable) {collapse(mt_flur_ll);} else {expand(mt_flur_ll);}}});}private void applyBlur() {bg_ll_flur.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {@Overridepublic boolean onPreDraw() {bg_ll_flur.getViewTreeObserver().removeOnPreDrawListener(this);bg_ll_flur.buildDrawingCache();Bitmap bmp = bg_ll_flur.getDrawingCache();blurRS(bmp, bg_ll_bg);return true;}});}/** * 根据图片压缩放大模糊原理 效果较差，但能够兼容2.3+ * * @param bkg * @param view */@TargetApi(Build.VERSION_CODES.JELLY_BEAN)private void blur(Bitmap bkg, View view) {float scaleFactor = 1;float radius = 20;// ====快速模糊scaleFactor = 8;radius = 2;// ====Bitmap overlay = Bitmap.createBitmap((int) (view.getMeasuredWidth() / scaleFactor),(int) (view.getMeasuredHeight() / scaleFactor),Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(overlay);canvas.translate(-view.getLeft() / scaleFactor, -view.getTop()/ scaleFactor);canvas.scale(1 / scaleFactor, 1 / scaleFactor);Paint paint = new Paint();paint.setFlags(Paint.FILTER_BITMAP_FLAG);canvas.drawBitmap(bkg, 0, 0, paint);overlay = FastBlur.doBlur(overlay, (int) radius, true);if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {view.setBackground(new BitmapDrawable(getResources(), overlay));} else {view.setBackgroundDrawable(new BitmapDrawable(getResources(),overlay));}}/** * 根据Android自己的兼容包，如果使用系统自带的需要4.4+，使用V8兼容包，能够兼容4.2+ * * @param bkg * @param view */@TargetApi(Build.VERSION_CODES.JELLY_BEAN)private void blurRS(Bitmap bkg, View view) {float scaleFactor = 1;float radius = 20;// ====快速模糊scaleFactor = 8;radius = 2;// ====Bitmap overlay = Bitmap.createBitmap((int) (view.getMeasuredWidth() / scaleFactor),(int) (view.getMeasuredHeight() / scaleFactor),Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(overlay);canvas.translate(-view.getLeft() / scaleFactor, -view.getTop()/ scaleFactor);canvas.scale(1 / scaleFactor, 1 / scaleFactor);Paint paint = new Paint();paint.setFlags(Paint.FILTER_BITMAP_FLAG);canvas.drawBitmap(bkg, 0, 0, paint);RenderScript rs = RenderScript.create(getApplicationContext());Allocation overlayAlloc = Allocation.createFromBitmap(rs, overlay);ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(rs,overlayAlloc.getElement());blur.setInput(overlayAlloc);blur.setRadius(radius);blur.forEach(overlayAlloc);overlayAlloc.copyTo(overlay);if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {view.setBackground(new BitmapDrawable(getResources(), overlay));} else {view.setBackgroundDrawable(new BitmapDrawable(getResources(),overlay));}rs.destroy();}public void expand(final View v) {if (adapter.getCount() > 4) {HEADHEIGHT = dip2px(4 * 50 + 30 + 70 + 10);} else {HEADHEIGHT = dip2px(adapter.getCount() * 50 + 30 + 70);}v.measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);final int targtetHeight = HEADHEIGHT;v.getLayoutParams().height = 0;v.setVisibility(View.VISIBLE);Animation a = new Animation() {@Overrideprotected void applyTransformation(float interpolatedTime,Transformation t) {v.getLayoutParams().height = interpolatedTime == 1 ? targtetHeight: (int) (targtetHeight * interpolatedTime);v.requestLayout();}@Overridepublic boolean willChangeBounds() {return true;}};a.setDuration(150);v.startAnimation(a);a.setAnimationListener(new AnimationListener() {@Overridepublic void onAnimationStart(Animation arg0) {bg_ll_flur.setVisibility(View.INVISIBLE);bg_ll_bg.setVisibility(View.VISIBLE);applyBlur();}@Overridepublic void onAnimationRepeat(Animation arg0) {}@Overridepublic void onAnimationEnd(Animation arg0) {expandable = true;}});}public void collapse(final View v) {final int initialHeight = v.getMeasuredHeight();if (initialHeight > HEADHEIGHT) {HEADHEIGHT = initialHeight;}Animation a = new Animation() {@Overrideprotected void applyTransformation(float interpolatedTime,Transformation t) {if (interpolatedTime == 1) {v.setVisibility(View.GONE);} else {v.getLayoutParams().height = initialHeight- (int) (initialHeight * interpolatedTime);v.requestLayout();}}@Overridepublic boolean willChangeBounds() {return true;}};a.setDuration(150);v.startAnimation(a);a.setAnimationListener(new AnimationListener() {@Overridepublic void onAnimationStart(Animation arg0) {bg_ll_flur.setVisibility(View.VISIBLE);bg_ll_bg.setVisibility(View.GONE);}@Overridepublic void onAnimationRepeat(Animation arg0) {}@Overridepublic void onAnimationEnd(Animation arg0) {expandable = false;}});}private class LMtAdapter extends BaseAdapter {private ViewHolder holder;@Overridepublic int getCount() {return 15;}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}@Overridepublic View getView(final int position, View convertView,ViewGroup parent) {if (convertView == null) {convertView = LayoutInflater.from(getApplicationContext()).inflate(R.layout.mm_item, parent, false);holder = new ViewHolder(convertView);}switch (position % 3) {case 0:holder.img.setImageResource(R.drawable.ter);break;case 1:holder.img.setImageResource(R.drawable.sfas);break;case 2:holder.img.setImageResource(R.drawable.swq);break;default:holder.img.setImageResource(R.drawable.swq);break;}return convertView;}class ViewHolder {private ImageView img;ViewHolder(View view) {img = (ImageView) view.findViewById(R.id.mm_img);}}}private class MtAdapter extends BaseAdapter {@Overridepublic int getCount() {return 5;}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}@Overridepublic View getView(final int position, View convertView,ViewGroup parent) {if (convertView == null) {convertView = LayoutInflater.from(getApplicationContext()).inflate(R.layout.mt_item, parent, false);}return convertView;}}public int dip2px(float dipValue) {final float scale = getResources().getDisplayMetrics().density;return (int) (dipValue * scale + 0.5f);}}文件地址：

，努力爱一个人。付出，不一定会有收获；