Android 仿今日头条频道管理（上）（GridView之间Item的移动和拖拽）

前言

经常逛今日头条、发现它的频道管理功能做的特别赞，交互体验非常好、如图：

它是2个gridview组成、2个gridview之间的Item是可以相互更换的、而且我的频道的Item是可以拖拽进行排序。仔细观察、今日头条有些细节做的的非常好，当一个gridview1的item移动到另一个gridview2时、gridview1的item不会立即消失、而是有一个没有内容的背景框、等item移动gridview2操作完毕才会消失、并且gridview2在gridview1的Item到达之前也有一个没有内容的背景框，等到达后覆盖。给用户一个很强的交互体验，很赞。而且在item拖拽移动排序时、拖拽的item会变大变色、效果很赞，体验极好。感兴趣的话可以下一个今日头条的客户端看看。当看到这么赞的交互体验，我就想看看是怎么实现的，这篇博客先讲2个Gridview之间item的移动，下一篇在带来gridview的拖拽排序。

实现思路

要实现2个gridview之间的Item相互移动：

1、首先我们获取我们点击的位置、处于gridview哪个位置

2、获取位置后、我们就能拿到这个Item的View，我们获取item绘制缓存的Bitmap对象。

3、将Bitmap设置的一个Imageview上，然后将这个ImageView放到一个容器中去进行移动操作，这样可能有人有疑问，为什么不直接把item放到容器中去呢，是因为item已经有自己的父容器gridview，所以我们new一个Imageview来代替item

4、然后我们将imageview移动到另一个gridview的最后一个位置。

5、最后刷新2个gridview的视图、就能实现我们所见的效果。

实现代码

主程序代码：

package com.test.drag;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
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.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.test.drag.view.MyGridView;

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

public class MainActivity extends AppCompatActivity implements OnItemClickListener {
    private MyGridView mUserGv, mOtherGv;
    private List mUserList = new ArrayList<>();
    private List mOtherList = new ArrayList<>();
    private OtherAdapter mUserAdapter, mOtherAdapter;

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

    public void initView() {
        mUserGv = (MyGridView) findViewById(R.id.userGridView);
        mOtherGv = (MyGridView) findViewById(R.id.otherGridView);
        mUserList.add("推荐");
        mUserList.add("热点");
        mUserList.add("上海");
        mUserList.add("时尚");
        mUserList.add("科技");
        mUserList.add("体育");
        mUserList.add("军事");
        mUserList.add("财经");
        mUserList.add("网络");
        mOtherList.add("汽车");
        mOtherList.add("房产");
        mOtherList.add("社会");
        mOtherList.add("情感");
        mOtherList.add("女人");
        mOtherList.add("旅游");
        mOtherList.add("健康");
        mOtherList.add("美女");
        mOtherList.add("游戏");
        mOtherList.add("数码");
        mOtherList.add("娱乐");
        mOtherList.add("探索");
        mUserAdapter = new OtherAdapter(this, mUserList,true);
        mOtherAdapter = new OtherAdapter(this, mOtherList,false);
        mUserGv.setAdapter(mUserAdapter);
        mOtherGv.setAdapter(mOtherAdapter);
        mUserGv.setOnItemClickListener(this);
        mOtherGv.setOnItemClickListener(this);
    }

    /**
     *获取点击的Item的对应View，
     *因为点击的Item已经有了自己归属的父容器MyGridView，所有我们要是有一个ImageView来代替Item移动
     * @param view
     * @return
     */
    private ImageView getView(View view) {
        view.destroyDrawingCache();
        view.setDrawingCacheEnabled(true);
        Bitmap cache = Bitmap.createBitmap(view.getDrawingCache());
        view.setDrawingCacheEnabled(false);
        ImageView iv = new ImageView(this);
        iv.setImageBitmap(cache);
        return iv;
    }
    /**
     * 获取移动的VIEW，放入对应ViewGroup布局容器
     * @param viewGroup
     * @param view
     * @param initLocation
     * @return
     */
    private View getMoveView(ViewGroup viewGroup, View view, int[] initLocation) {
        int x = initLocation[0];
        int y = initLocation[1];
        viewGroup.addView(view);
        LinearLayout.LayoutParams mLayoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        mLayoutParams.leftMargin = x;
        mLayoutParams.topMargin = y;
        view.setLayoutParams(mLayoutParams);
        return view;
    }

    /**
     * 创建移动的ITEM对应的ViewGroup布局容器
     * 用于存放我们移动的View
     */
    private ViewGroup getMoveViewGroup() {
        //window中最顶层的view
        ViewGroup moveViewGroup = (ViewGroup) getWindow().getDecorView();
        LinearLayout moveLinearLayout = new LinearLayout(this);
        moveLinearLayout.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
        moveViewGroup.addView(moveLinearLayout);
        return moveLinearLayout;
    }
    /**
     * 点击ITEM移动动画
     *
     * @param moveView
     * @param startLocation
     * @param endLocation
     * @param moveChannel
     * @param clickGridView
     */
    private void MoveAnim(View moveView, int[] startLocation, int[] endLocation, final String moveChannel,
                          final GridView clickGridView, final boolean isUser) {
        int[] initLocation = new int[2];
        //获取传递过来的VIEW的坐标
        moveView.getLocationInWindow(initLocation);
        //得到要移动的VIEW,并放入对应的容器中
        final ViewGroup moveViewGroup = getMoveViewGroup();
        final View mMoveView = getMoveView(moveViewGroup, moveView, initLocation);
        //创建移动动画
        TranslateAnimation moveAnimation = new TranslateAnimation(
                startLocation[0], endLocation[0], startLocation[1],
                endLocation[1]);
        moveAnimation.setDuration(300L);//动画时间
        //动画配置
        AnimationSet moveAnimationSet = new AnimationSet(true);
        moveAnimationSet.setFillAfter(false);//动画效果执行完毕后，View对象不保留在终止的位置
        moveAnimationSet.addAnimation(moveAnimation);
        mMoveView.startAnimation(moveAnimationSet);
        moveAnimationSet.setAnimationListener(new Animation.AnimationListener() {

            @Override
            public void onAnimationStart(Animation animation) {
            }

            @Override
            public void onAnimationRepeat(Animation animation) {
            }

            @Override
            public void onAnimationEnd(Animation animation) {
                moveViewGroup.removeView(mMoveView);
                // 判断点击的是DragGrid还是OtherGridView
                if (isUser) {
                    mOtherAdapter.setVisible(true);
                    mOtherAdapter.notifyDataSetChanged();
                    mUserAdapter.remove();
                } else {
                    mUserAdapter.setVisible(true);
                    mUserAdapter.notifyDataSetChanged();
                    mOtherAdapter.remove();
                }
            }
        });
    }

    @Override
    public void onItemClick(AdapterView parent, View view, final int position, long id) {
        switch (parent.getId()) {
            case R.id.userGridView:
                //position为 0，1 的不可以进行任何操作
                if (position != 0 && position != 1) {
                    final ImageView moveImageView = getView(view);
                    if (moveImageView != null) {
                        TextView newTextView = (TextView) view.findViewById(R.id.text_item);
                        final int[] startLocation = new int[2];
                        newTextView.getLocationInWindow(startLocation);
                        final String channel = ((OtherAdapter) parent.getAdapter()).getItem(position);//获取点击的频道内容
                        mOtherAdapter.setVisible(false);
                        //添加到最后一个
                        mOtherAdapter.addItem(channel);
                        new Handler().postDelayed(new Runnable() {
                            public void run() {
                                try {
                                    int[] endLocation = new int[2];
                                    //获取终点的坐标
                                    mOtherGv.getChildAt(mOtherGv.getLastVisiblePosition()).getLocationInWindow(endLocation);
                                    MoveAnim(moveImageView, startLocation, endLocation, channel, mUserGv, true);
                                    mUserAdapter.setRemove(position);
                                } catch (Exception localException) {
                                }
                            }
                        }, 50L);
                    }
                }
                break;
            case R.id.otherGridView:
                final ImageView moveImageView = getView(view);
                if (moveImageView != null) {
                    TextView newTextView = (TextView) view.findViewById(R.id.text_item);
                    final int[] startLocation = new int[2];
                    newTextView.getLocationInWindow(startLocation);
                    final String channel = ((OtherAdapter) parent.getAdapter()).getItem(position);
                    mUserAdapter.setVisible(false);
                    //添加到最后一个
                    mUserAdapter.addItem(channel);
                    new Handler().postDelayed(new Runnable() {
                        public void run() {
                            try {
                                int[] endLocation = new int[2];
                                //获取终点的坐标
                                mUserGv.getChildAt(mUserGv.getLastVisiblePosition()).getLocationInWindow(endLocation);
                                MoveAnim(moveImageView, startLocation, endLocation, channel, mOtherGv,false);
                                mOtherAdapter.setRemove(position);
                            } catch (Exception localException) {
                            }
                        }
                    }, 50L);
                }
                break;
            default:
                break;
        }
    }
}

适配器代码：

package com.test.drag;

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

import java.util.List;

/**
 * Created by fuweiwei on 2016/1/8.
 */
public class OtherAdapter extends BaseAdapter {

    private Context context;
    public List channelList;
    private TextView item_text;
    /** 是否可见 在移动动画完毕之前不可见，动画完毕后可见*/
    boolean isVisible = true;
    /** 要删除的position */
    public int remove_position = -1;
    /** 是否是用户频道 */
    private boolean isUser = false;

    public OtherAdapter(Context context, List channelList ,boolean isUser) {
        this.context = context;
        this.channelList = channelList;
        this.isUser = isUser;
    }

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

    @Override
    public String getItem(int position) {
        if (channelList != null && channelList.size() != 0) {
            return channelList.get(position);
        }
        return null;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = LayoutInflater.from(context).inflate(R.layout.adapter_mygridview_item, null);
        item_text = (TextView) view.findViewById(R.id.text_item);
        String channel = getItem(position);
        item_text.setText(channel);
        if(isUser){
            if ((position == 0) || (position == 1)){
                item_text.setEnabled(false);
            }
        }
        if (!isVisible && (position == -1 + channelList.size())){
            item_text.setText("");
            item_text.setSelected(true);
            item_text.setEnabled(true);
        }
        if(remove_position == position){
            item_text.setText("");
        }
        return view;
    }

    /** 获取频道列表 */
    public List getChannnelLst() {
        return channelList;
    }

    /** 添加频道列表 */
    public void addItem(String channel) {
        channelList.add(channel);
        notifyDataSetChanged();
    }

    /** 设置删除的position */
    public void setRemove(int position) {
        remove_position = position;
        notifyDataSetChanged();
        // notifyDataSetChanged();
    }

    /** 删除频道列表 */
    public void remove() {
        channelList.remove(remove_position);
        remove_position = -1;
        notifyDataSetChanged();
    }
    /** 设置频道列表 */
    public void setListDate(List list) {
        channelList = list;
    }

    /** 获取是否可见 */
    public boolean isVisible() {
        return isVisible;
    }

    /** 设置是否可见 */
    public void setVisible(boolean visible) {
        isVisible = visible;
    }

}

至于之前说的很赞的交互体验是怎么实现的：

1、在点击gridview1的item时（也就是Imageview移动动画开始时），我们将所点击的内容置为空，

2、在gridview1点击的同时我们在gridview2的最后面加一个我们刚点击的item，但内容显示也是空

3、当imageview移动动画结束后，我们将gridview1所点击的item移除、重新刷新界面，而gridview2我们只要设置最后一个内容显示、刷新视图。

这样就能实现今天头条一样超赞的交互体验。

其它代码：

package com.test.drag.view;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.GridView;

/**
 * Created by fuweiwei on 2016/1/8.
 */
public class MyGridView extends GridView {
    public MyGridView(Context paramContext, AttributeSet paramAttributeSet) {
        super(paramContext, paramAttributeSet);
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
                MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, expandSpec);
    }
}

布局：

实现的效果如下：

是不是效果一模一样，很喜欢这样交互体验，这里只介绍了gridview之间item的移动，至于gridview的Item的拖拽比较复杂、会在下一篇博客记录。

源码下载