android recyclerview 滑动删除 android recyclerview item动画

关于，RecycleView，最新版的android已经不用v7了，用这个 androidx.recyclerview.widget.RecyclerView

主页面设置一个RecycleVIew作为显示，这里用xml指定动画， android:layoutAnimation="@anim/layout_animation_fall_down"

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <androidx.recyclerview.widget.RecyclerView
        android:layoutAnimation="@anim/layout_animation_fall_down"
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />
</LinearLayout>

然后首先写item的动画/res/anim/layout_animation_fall_down

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="1000">
    <translate
        android:fromYDelta="-20%"
        android:toYDelta="0"
        android:interpolator="@android:anim/decelerate_interpolator"
        />
    <alpha
        android:fromAlpha="0"
        android:toAlpha="1"
        android:interpolator="@android:anim/decelerate_interpolator"
        />
    <scale
        android:fromXScale="105%"
        android:fromYScale="105%"
        android:toXScale="100%"
        android:toYScale="100%"
        android:pivotX="50%"
        android:pivotY="50%"
        android:interpolator="@android:anim/decelerate_interpolator"
        />
</set>

然后设置layout动画的xml文件，在里面指定上述文件

<?xml version="1.0" encoding="utf-8"?>
<layoutAnimation
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:animation="@anim/item_animation_fall_down"
android:delay="5%"
    android:animationOrder="normal"

    />

这里需要注意，delay代表每个itme执行动画到多少，下个item开始加载，不知道为什么，设置的过大，当item过多时候会卡顿，不知道是不是虚拟机的问题。

然后顺便回顾一下Recycleview的用法，首先写我们的类，这里用的是水果类

package com.example.testviewgroup.PO;
public class Fruit {
    private String name;
    private int imageId;
    public Fruit (String name,int imageId){
        this.name = name;
        this.imageId = imageId;
    }
    public String getName() {
        return name;
    }
    public int getImageId() {
        return imageId;
    }
}

然后用重写的适配器

package com.example.testviewgroup.Adapters;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.recyclerview.widget.RecyclerView;

import com.example.testviewgroup.PO.Fruit;
import com.example.testviewgroup.R;

import java.util.List;
public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder> {

    private List<Fruit> mFruitList;

    static class ViewHolder extends RecyclerView.ViewHolder {
        ImageView fruitImage;
        TextView fruitName;

        public ViewHolder(View view) {
            super(view);
            fruitImage = (ImageView) view.findViewById(R.id.fruit_image);
            fruitName = (TextView) view.findViewById(R.id.fruitname);
        }

    }

    public FruitAdapter(List<Fruit> fruitList) {
        mFruitList = fruitList;
    }

    @Override

    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item, parent, false);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

        Fruit fruit = mFruitList.get(position);
        holder.fruitImage.setImageResource(fruit.getImageId());
        holder.fruitName.setText(fruit.getName());
    }

    @Override
    public int getItemCount() {
        return mFruitList.size();
    }
}

    @Override 标注的是三个需要重写的方法，然后MainActivity里写

public class MainActivity extends AppCompatActivity {

    private List<Fruit> fruitList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruits();
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        FruitAdapter adapter = new FruitAdapter(fruitList);
        recyclerView.setAdapter(adapter);
    }

    private void initFruits() {
        for (int i = 0; i < 20; i++) {
            Fruit apple = new Fruit("Apple", R.drawable.nuoshou);
            fruitList.add(apple);
        }
    }
}

这样就实现了酷炫的特效