Android 5.0新控件—RecyclerView的基本用法
2016-09-01 本文已影响1264人
程序员K哥
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RecyclerView是Google在API 21下support.V7包里的控件,用来替代ListView。
官网对RecyclerView的描述为:A flexible view for providing a limited window into a large data set。
个人翻译(英文水平有限...):RecyclerView是为一个大数据的集合提供一个受限制的窗口的灵活性的View。
一、使用RecyclerView的前提条件
想使用RecyclerView,一定要在build.gradle中引入compile 'com.android.support:recyclerview-v7:24.0.0'
依赖。
二、使用RecyclerView的优缺点
优点:
- 1 RecyclerView强制封装ViewHolder
- 2 相当轻松的设置布局管理器以控制Item的布局方式,横向、竖向以及瀑布流方式
- 3 可设置Item操作的动画,删除或者添加等
- 4 通过ItemDecoration,控制Item间的间隔,可自己绘制
缺点:
- 需要自己实现OnItemClickListener点击事件(这么实用的需求,Google竟然让我们自己实现...)
三、RecyclerView的具体实现
先来看下效果图:
图例1.png 图例2.png 图例3.png使用方法如下:
1.在xml布局里面直接添加RecyclerView控件(跟ListView差不多),在布局中我添加了一个Spinner按钮来选择不同的Item展示模式,两个Button按钮用来添加或者删除Item。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.it.keithxiaoy.recycleview.MainActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycleview"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<Spinner
android:layout_alignParentBottom="true"
android:id="@+id/spinner"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
</Spinner>
<Button
android:layout_alignParentBottom="true"
android:layout_toRightOf="@+id/spinner"
android:id="@+id/b1"
android:text="add"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:layout_alignParentBottom="true"
android:layout_toRightOf="@+id/b1"
android:id="@+id/b2"
android:text="delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
2.Activity界面分析
- 1 先找到RecyclerView控件,然后设置一个默认的Item显示模式,并将自己封装的Adapter和RecycleView绑定
mRecyclerView = (RecyclerView) findViewById(R.id.recycleview);
mLinearLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
myRecycleViewAdapter = new MyRecycleViewAdapter(datas);
mRecyclerView.setAdapter(myRecycleViewAdapter);
- 2 设置item的点击事件,并设置点击Item时的动画效果
//设置item的点击事件
myRecycleViewAdapter.setOnItemClickListener(new MyRecycleViewAdapter.OnItemClickListener() {
@Override
public void onItemClick(final View view, int position) {
//设置点击动画
view.animate()
.translationZ(15f)
.setDuration(300)
.setListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
super.onAnimationEnd(animation);
view.animate()
.translationZ(1f)
.setDuration(500)
.start();
}
}).start();
}
});
- 3 根据Spinner的选择,Item转换展示效果
mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
if (position == 0){
mRecyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
}else if (position == 1){
mRecyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));
}else if (position == 2)
mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
}
下面是完整的Activity的代码:
package com.it.keithxiaoy.recycleview;
import ...
/** * Created by KeithXiaoY on 2016/8/31. */
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private RecyclerView mRecyclerView;
private MyRecycleViewAdapter myRecycleViewAdapter;
private List<String> datas = new ArrayList<>();
private LinearLayoutManager mLinearLayoutManager;
private Spinner mSpinner;
private static final String[] m={"竖着的RecycleView","GridView类型的RecycleView","瀑布流","还没想好其他效果","其他"};
private ArrayAdapter<String> adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = (RecyclerView) findViewById(R.id.recycleview);
Button add = (Button) findViewById(R.id.b1);
Button delete = (Button) findViewById(R.id.b2);
add.setOnClickListener(this);
delete.setOnClickListener(this);
mSpinner = (Spinner) findViewById(R.id.spinner);
//将可选内容与ArrayAdapter连接起来
adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,m);
//设置下拉列表的风格
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
//将adapter 添加到spinner中
mSpinner.setAdapter(adapter);
//设置默认值
mSpinner.setVisibility(View.VISIBLE);
mLinearLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
// do not change the size of the RecyclerView
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
if (position == 0){
mRecyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
}else if (position == 1){
mRecyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));
}else if (position == 2)
mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
for (int i = 0; i < 3 ; i++) {
datas.add("KeithXiaoY");
}
myRecycleViewAdapter = new MyRecycleViewAdapter(datas);
mRecyclerView.setAdapter(myRecycleViewAdapter);
//设置item的点击事件
myRecycleViewAdapter.setOnItemClickListener(new MyRecycleViewAdapter.OnItemClickListener() {
@Override
public void onItemClick(final View view, int position) {
//设置点击动画
view.animate()
.translationZ(15f)
.setDuration(300)
.setListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
super.onAnimationEnd(animation);
view.animate()
.translationZ(1f)
.setDuration(500)
.start();
}
}).start();
}
});
}
public void add(View view){
datas.add("KeithXiaoY");
int position = datas.size();
if (position > 0){
myRecycleViewAdapter.notifyDataSetChanged();
}
}
public void delete(View view){
int position = datas.size();
if (position > 0){
datas.remove(position - 1);
myRecycleViewAdapter.notifyDataSetChanged();
}
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.b1 :
add(view);
break;
case R.id.b2 :
delete(view);
break;
}
}
}
3.RecycleView的Adapter和ListView的Adapter还是有点区别,来看看RecycleView的Adapter
package com.it.keithxiaoy.recycleview;
import ...
/** * Created by KeithXiaoY on 2016/8/31. */
public class MyRecycleViewAdapter extends RecyclerView.Adapter<MyRecycleViewAdapter.ViewHolder> {
private List<String> mData;
public MyRecycleViewAdapter(List<String> data) {
mData = data ;
}
public OnItemClickListener itemClickListener;
public void setOnItemClickListener(OnItemClickListener itemClickListener){
this.itemClickListener = itemClickListener;
}
public interface OnItemClickListener{
void onItemClick(View view, int position);
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_view, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.textView.setText(mData.get(position)+ position);
}
@Override
public int getItemCount() {
return mData.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public TextView textView ;
public ViewHolder(View itemView) {
super(itemView);
textView = (TextView) itemView;
textView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (itemClickListener != null){
itemClickListener.onItemClick(view,getPosition());
}
}
}
}
4.RecycleView的item布局就是一个TextView,这里代码就不贴了,实际项目中有一些是结合CardView配合使用。
注意事项:
-
1 Adapter类里面继承RecycleView.Adapter括号里面的泛型类型是你自己创建的Adapter的ViewHolder!
图例4.png -
2 Adapter类里面需要自己手动实现OnItemClickListener!
图例5.png
结束语:
本文只是介绍了RecycleView的基本用法,还有很多高级的用法,本人还未领会。不足之处,诸君谅解...
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