Android程序設計-RecyclerView的使用
【定義】
看到這個標題,也許你會問什么是RecyclerView?其實開始的時候我也不知道- -,下面小編將帶領大家領略RecyclerView的強大之處
【描述】
看完這個我想大家應該知道了吧,這個東西和ListView一樣,只不過,這個…在設計的時候不需要考慮上述幾個功能,即使要實現這幾個功能,也是很簡單的,僅僅需要幾句話就可以搞定的
【使用】
使用的時候需要導入recyclerview-v7-21.0.0的jar包,然后在布局文件中添加這個控件
<android.support.v7.widget.RecyclerView/>
---------------------------------------------------------------我是一個帥帥的分割線-------------------------------------------------------
【案例】
小編將通過一個案例實現RecyclerView的使用,下面請看這個案例的實現效果
【關鍵步驟】
1.在布局文件中添加了對用的控件后,我們需要書寫代碼,既然和ListView肯定需要適配器,下面我們來看下適配器
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.
* 繼承RecyclerView,實現ListView的效果
* RecyclerView中google強烈要求使用ViewHolder
*/
public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder>{
private List<String> mData;
private Context context;
private LayoutInflater mInflater;
/**
* 聲明一個接口,用于實現點擊事件
*/
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;
}
/**構造方法的實現**/
public SimpleAdapter(List<String> mData,Context context){
this.mData=mData;
this.context=context;
mInflater=LayoutInflater.from(context);
}
/**
* 創建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;
}
/**
* 綁定ViewHolder類,即給控件賦值
* @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類,這個類的作用主要用于實例化控件
*/
class MyViewHolder extends RecyclerView.ViewHolder{
TextView tv; //聲明控件
public MyViewHolder(View itemView) {
super(itemView);
/**初始化控件**/
tv= (TextView) itemView.findViewById(R.id.tv);
}
}ps:
代碼中我們可以看到我們繼承了RecyclerView.Adapter<MyViewHolder>,實現了未實現的方法,但是 一定要注意,google在這里要求必須實現ViewHolder這個類,我們通過代碼知道,通過設計了ViewHolder使我們的類更加的簡潔了,更 重要的是我們的代碼更加的實用了。
2.我們來看下MainActivity中的代碼:
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);
//設置RecyclerView的布局管理
LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
recyclerView.setLayoutManager(layoutManager);
//設置RecyclerView的item間的分割線
// recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
//設置RecyclerView的動畫
recyclerView.setItemAnimator(new DefaultItemAnimator());
//設置監聽事件
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);
}
/**
* 加載數據源
*/
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:
適配器的使用和ListView的使用一樣,但是這時候當我們運行程序會發現沒有分割線,整個頁面成一個了,所以我們需要使用addItemDecoration添加分割線
設置RecyclerView的item間的分割線
recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));Comic Sans MS在分割線的部分我們需要引入github中的一個分割線文件:
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中設計布局管理?這個布局管理可以讓你的頁面實現ListView和GridView的自由切換
//設置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和刪除item的動畫?
(附錄動畫效果的Github鏈接: https://github.com/gabrielemariotti/RecyclerViewItemAnimators )
//設置RecyclerView的動畫 recyclerView.setItemAnimator(new DefaultItemAnimator());
如何在對Recycler中的item設置監聽事件?這個監聽事件系統不提供,需要我們手動編寫
--->我們需要在適配器添加一個接口:
/**
* 聲明一個接口,用于實現點擊事件
*/
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;
}
/**構造方法的實現**/
public SimpleAdapter(List<String> mData,Context context){
this.mData=mData;
this.context=context;
mInflater=LayoutInflater.from(context);
}--->在onBindViewHolder中設置監聽事件的方法
/**
* 綁定ViewHolder類,即給控件賦值
* @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中調用如
//設置監聽事件
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();
}
});上述即為RecyclerView的簡單實用,程序中的其他樣式敬請參考【源碼】
【視頻】
【源碼】