【定义】
看到这个标题,也许你会问什么是RecyclerView?其实开始的时候我也不知道- -,下面小编将带领大家领略RecyclerView的强大之处
【描述】
看完这个我想大家应该知道了吧,这个东西和ListView一样,只不过,这个…在设计的时候不需要考虑上述几个功能,即使要实现这几个功能,也是很简单的,仅仅需要几句话就可以搞定的
【使用】
使用的时候需要导入recyclerview-v7-21.0.0的jar包,然后在布局文件中添加这个控件
<android.support.v7.widget.RecyclerView/>
---------------------------------------------------------------我是一个帅帅的分割线-------------------------------------------------------
【案例】
小编将通过一个案例实现RecyclerView的使用,下面请看这个案例的实现效果
【关键步骤】
1.在布局文件中添加了对用的控件后,我们需要书写代码,既然和ListView肯定需要适配器,下面我们来看下适配器
package org.monster.recyclerviewdemo; import android.content.Context; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import java.util.List; /** * Created by monster on 2015/7/9. * 继承RecyclerView,实现ListView的效果 * RecyclerView中google强烈要求使用ViewHolder */ public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder>{ private List<String> mData; private Context context; private LayoutInflater mInflater; /** * 声明一个接口,用于实现点击事件 */ public interface OnItemClickListener{ void OnItemClick(int position,View view); void OnItemLongClick(int position,View view); } private OnItemClickListener mOnItemClickListener; public void setOnItemClickListener(OnItemClickListener listener){ this.mOnItemClickListener=listener; } /**构造方法的实现**/ public SimpleAdapter(List<String> mData,Context context){ this.mData=mData; this.context=context; mInflater=LayoutInflater.from(context); } /** * 创建ViewHolder * @param parent * @param viewType * @return */ @Override public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view=mInflater.inflate(R.layout.recycler_item,parent,false); MyViewHolder viewHolder=new MyViewHolder(view); return viewHolder; } /** * 绑定ViewHolder类,即给控件赋值 * @param holder * @param position */ @Override public void onBindViewHolder(final MyViewHolder holder, final int position) { holder.tv.setText(mData.get(position)); if (mOnItemClickListener!=null){ holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int LayoutPosition=holder.getLayoutPosition(); //得到布局的position mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView); } }); //longclickListener holder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { int LayoutPosition=holder.getLayoutPosition(); //得到布局的position mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView); return false; } }); } } @Override public int getItemCount() { return mData.size(); } public void addData(int position){ mData.add(position,"Insert One"); notifyItemInserted(position); } public void deleteData(int position){ mData.remove(position); notifyItemRemoved(position); } } /** * ViewHolder类,这个类的作用主要用于实例化控件 */ class MyViewHolder extends RecyclerView.ViewHolder{ TextView tv; //声明控件 public MyViewHolder(View itemView) { super(itemView); /**初始化控件**/ tv= (TextView) itemView.findViewById(R.id.tv); } }
ps:
代码中我们可以看到我们继承了RecyclerView.Adapter<MyViewHolder>,实现了未实现的方法,但是一定要注意,google在这里要求必须实现ViewHolder这个类,我们通过代码知道,通过设计了ViewHolder使我们的类更加的简洁了,更重要的是我们的代码更加的实用了。
2.我们来看下MainActivity中的代码:
package org.monster.recyclerviewdemo; import android.content.Intent; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.support.v7.widget.DefaultItemAnimator; import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.StaggeredGridLayoutManager; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Switch; import android.widget.Toast; import java.util.ArrayList; import java.util.List; public class MainActivity extends ActionBarActivity { private RecyclerView recyclerView; private List<String> mDatas; private SimpleAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initDatas(); initView(); adapter=new SimpleAdapter(mDatas,this); recyclerView.setAdapter(adapter); //设置RecyclerView的布局管理 LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false); recyclerView.setLayoutManager(layoutManager); //设置RecyclerView的item间的分割线 // recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST)); //设置RecyclerView的动画 recyclerView.setItemAnimator(new DefaultItemAnimator()); //设置监听事件 adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() { @Override public void OnItemClick(int position, View view) { Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show(); } @Override public void OnItemLongClick(int position, View view) { Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show(); } }); } private void initView() { recyclerView= (RecyclerView) findViewById(R.id.RecyclerView); } /** * 加载数据源 */ private void initDatas() { mDatas=new ArrayList<String>(); for(int i='A';i<'z';i++){ mDatas.add(" "+(char)i); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); switch (id){ case R.id.action_add: adapter.addData(1); break; case R.id.action_delete: adapter.deleteData(1); break; case R.id.action_listview: recyclerView.setLayoutManager(new LinearLayoutManager(this)); break; case R.id.action_gridview: recyclerView.setLayoutManager(new GridLayoutManager(this,3)); break; case R.id.action_hor_gridview: recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.HORIZONTAL)); break; case R.id.action_staggered: Intent i=new Intent(this,StaggerActivity.class); startActivity(i); break; } return super.onOptionsItemSelected(item); } }
PS:
适配器的使用和ListView的使用一样,但是这时候当我们运行程序会发现没有分割线,整个页面成一个了,所以我们需要使用addItemDecoration添加分割线
设置RecyclerView的item间的分割线 recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
Comic Sans MS在分割线的部分我们需要引入github中的一个分割线文件:
package org.monster.recyclerviewdemo; /* * Copyright (C) 2014 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.util.Log; import android.view.View; /** * This class is from the v7 samples of the Android SDK. It's not by me! * <p/> * See the license above for details. */ public class DividerItemDecoration extends RecyclerView.ItemDecoration { private static final int[] ATTRS = new int[] { android.R.attr.listDivider }; public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL; public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL; private Drawable mDivider; private int mOrientation; public DividerItemDecoration(Context context, int orientation) { final TypedArray a = context.obtainStyledAttributes(ATTRS); mDivider = a.getDrawable(0); a.recycle(); setOrientation(orientation); } public void setOrientation(int orientation) { if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) { throw new IllegalArgumentException("invalid orientation"); } mOrientation = orientation; } @Override public void onDraw(Canvas c, RecyclerView parent) { if (mOrientation == VERTICAL_LIST) { drawVertical(c, parent); } else { drawHorizontal(c, parent); } } public void drawVertical(Canvas c, RecyclerView parent) { final int left = parent.getPaddingLeft(); final int right = parent.getWidth() - parent.getPaddingRight(); final int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++) { final View child = parent.getChildAt(i); RecyclerView v = new RecyclerView( parent.getContext()); final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child .getLayoutParams(); final int top = child.getBottom() + params.bottomMargin; final int bottom = top + mDivider.getIntrinsicHeight(); mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } } public void drawHorizontal(Canvas c, RecyclerView parent) { final int top = parent.getPaddingTop(); final int bottom = parent.getHeight() - parent.getPaddingBottom(); final int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++) { final View child = parent.getChildAt(i); final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child .getLayoutParams(); final int left = child.getRight() + params.rightMargin; final int right = left + mDivider.getIntrinsicHeight(); mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } } @Override public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) { if (mOrientation == VERTICAL_LIST) { outRect.set(0, 0, 0, mDivider.getIntrinsicHeight()); } else { outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0); } } }
如何在RecyleView中设计布局管理?这个布局管理可以让你的页面实现ListView和GridView的自由切换
//设置RecyclerView的布局管理 LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false); recyclerView.setLayoutManager(layoutManager);
如何咋RecyclerView中增加添加item和删除item的动画?
(附录动画效果的Github链接:https://github.com/gabrielemariotti/RecyclerViewItemAnimators)
//设置RecyclerView的动画 recyclerView.setItemAnimator(new DefaultItemAnimator());
如何在对Recycler中的item设置监听事件?这个监听事件系统不提供,需要我们手动编写
--->我们需要在适配器添加一个接口:
/** * 声明一个接口,用于实现点击事件 */ public interface OnItemClickListener{ void OnItemClick(int position,View view); void OnItemLongClick(int position,View view); } private OnItemClickListener mOnItemClickListener; public void setOnItemClickListener(OnItemClickListener listener){ this.mOnItemClickListener=listener; } /**构造方法的实现**/ public SimpleAdapter(List<String> mData,Context context){ this.mData=mData; this.context=context; mInflater=LayoutInflater.from(context); }--->在onBindViewHolder中设置监听事件的方法
/** * 绑定ViewHolder类,即给控件赋值 * @param holder * @param position */ @Override public void onBindViewHolder(final MyViewHolder holder, final int position) { holder.tv.setText(mData.get(position)); if (mOnItemClickListener!=null){ holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int LayoutPosition=holder.getLayoutPosition(); //得到布局的position mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView); } }); //longclickListener holder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { int LayoutPosition=holder.getLayoutPosition(); //得到布局的position mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView); return false; } }); } }--->>在MainActivity中调用如
//设置监听事件 adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() { @Override public void OnItemClick(int position, View view) { Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show(); } @Override public void OnItemLongClick(int position, View view) { Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show(); } });
上述即为RecyclerView的简单实用,程序中的其他样式敬请参考【源码】
【视频】
【源码】