Android-RecyclerView-item上下切换（带动画实现）

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Android-RecyclerView-item上下切换（带动画实现）

<The rest of contents | 余下全文>

先来看下效果图:

github

已经封装：

RecyclerViewSwopItem

实现思路

首先一个RecyclerView、

然后在item的两个按钮上增加点击事件

在事件中对item和交换的item执行动画操作

难点：

难点在于如何获取要与之交换的itemview!

代码

我这里只实现了向上交换，向下交换同理可得！

package com.gloomyer.ndkdemo1;

import android.graphics.Rect;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.TranslateAnimation;
import android.widget.Button;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {


    static {
        System.loadLibrary("native-lib");
    }

    public native String stringFromJNI();

    RecyclerView mRecyclerView;

    List<String> mDatas;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
		//布局里面就一个充满屏幕的RecyclerView
        mRecyclerView = (RecyclerView) findViewById(R.id.mRecyclerView);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        MyAdapter mAdapter = new MyAdapter();
        initData();
        mRecyclerView.setAdapter(mAdapter);
      	//上下左右边距
        mRecyclerView.addItemDecoration(new RecyclerView.ItemDecoration() {
            @Override
            public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
                super.getItemOffsets(outRect, view, parent, state);
                outRect.left = 20;
                outRect.right = 20;
                outRect.top = 30;
            }
        });
    }
	//初始化数据
    private void initData() {
        mDatas = new ArrayList<>();
        for (int i = 0; i < 100; i++) {
            mDatas.add("item pos:" + i + "|| value:" + stringFromJNI());
        }
    }
	//view holder
    private class ViewHolder extends RecyclerView.ViewHolder {
        TextView pos;
        TextView value;
        Button top;
        Button bottom;
        View content;

        public ViewHolder(View itemView) {
            super(itemView);
            content = itemView;
            pos = (TextView) itemView.findViewById(R.id.pos);
            value = (TextView) itemView.findViewById(R.id.text);
            top = (Button) itemView.findViewById(R.id.top);
            bottom = (Button) itemView.findViewById(R.id.bottom);
        }
    }

    private class MyAdapter extends RecyclerView.Adapter<ViewHolder> {

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(MainActivity.this)
                    .inflate(R.layout.item, parent, false);//填充item布局，很简单的布局就不贴代码了
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, final int position) {
            //设置一下数据和按钮的显示
            holder.pos.setText("pos:" + position);
            holder.value.setText(mDatas.get(position));
            holder.top.setVisibility(position == 0 ? View.GONE : View.VISIBLE);
            holder.bottom.setVisibility(position == getItemCount() - 1 ? View.GONE : View.VISIBLE);
			
            holder.top.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    //执行向上动画
                    //平移
                    //获取两个item之间间距占一个item的百分比,间距为固定值30
                    final AnimationSet set
                            = new AnimationSet(true);
                    final float value = 30.0f / holder.content.getHeight();
                    TranslateAnimation translate
                            = new TranslateAnimation(
                            TranslateAnimation.RELATIVE_TO_SELF, 0,
                            TranslateAnimation.RELATIVE_TO_SELF, 0,
                            TranslateAnimation.RELATIVE_TO_SELF, 0,
                            TranslateAnimation.RELATIVE_TO_SELF, -1 - value);
                    translate.setFillAfter(true);
                    translate.setDuration(300);
                    set.addAnimation(translate);
                    set.setFillAfter(true);
                    set.setDuration(300);
                    set.setAnimationListener(new Animation.AnimationListener() {
                        @Override
                        public void onAnimationStart(Animation animation) {
                            holder.content.setAlpha(0.8f);
                        }

                        @Override
                        public void onAnimationEnd(Animation animation) {
                            holder.content.setAlpha(1.0f);
                            mDatas.add(position - 1, mDatas.remove(position));
                            notifyItemChanged(position);
                            notifyItemChanged(position - 1);
                        }

                        @Override
                        public void onAnimationRepeat(Animation animation) {

                        }
                    });


                    //移动上一个!
                  	//首先获取当前完整可见的item
                    final LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
                    int firstVisibleItemPosition = layoutManager.findFirstCompletelyVisibleItemPosition();
					
					//将要与之交换的item执行动画的操作封装成Runnable 后面会讲为什么！
                    Runnable run = new Runnable() {
                        @Override
                        public void run() {
                            //找到上一个viewholder
                            int firstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition();
                            int last = position - firstVisibleItemPosition;
                            final View view = mRecyclerView.getChildAt(last - 1);

                            AnimationSet set1
                                    = new AnimationSet(true);
                            TranslateAnimation translate1
                                    = new TranslateAnimation(
                                    TranslateAnimation.RELATIVE_TO_SELF, 0,
                                    TranslateAnimation.RELATIVE_TO_SELF, 0,
                                    TranslateAnimation.RELATIVE_TO_SELF, 0,
                                    TranslateAnimation.RELATIVE_TO_SELF, 1 + value);
                            translate1.setFillAfter(true);
                            translate1.setDuration(300);
                            set1.addAnimation(translate1);
                            set1.setFillAfter(true);
                            set1.setDuration(300);
                            set1.setAnimationListener(new Animation.AnimationListener() {
                                @Override
                                public void onAnimationStart(Animation animation) {
                                    view.setAlpha(0.8f);
                                }

                                @Override
                                public void onAnimationEnd(Animation animation) {
                                    view.setAlpha(1.0f);
                                }

                                @Override
                                public void onAnimationRepeat(Animation animation) {

                                }
                            });

                            holder.content.startAnimation(set);
                            view.startAnimation(set1);
                        }
                    };
					//如果第一个完全可见的item是大于或者等于自身的坐标，说明上一层view没有完整
                  	//需要滚动至要与之交换的view！
                    if (firstVisibleItemPosition >= position) {
                        //如果上下交换，作为当前上面的view不可见需要滑动到它完全可见为止
                        mRecyclerView.scrollToPosition(position - 1);
                        mRecyclerView.postDelayed(run, 100);
                        //这里着重说明下，因为上述的滚动是耗时操作
                        //如果需要执行这个那么后续操作需要延时，否则会nullpoint!
                    } else {
                        run.run();
                    }


                }
            });
        }

        @Override
        public int getItemCount() {
            return mDatas == null ? 0 : mDatas.size();
        }
    }
}