轉載學習http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2015/0327/2647.html
最終目的
模擬ListView的setOnItemClickListener()方法，調用者只須調用類似於setOnItemClickListener的東西就能獲得被點擊item的相關數據。
原理
爲RecyclerView的每個子item設置setOnClickListener，然後在onClick中再調用一次對外封裝的接口，將這個事件傳遞給外面的調用者。而“爲RecyclerView的每個子item設置setOnClickListener”在Adapter中設置。其實直接在onClick中也能完全處理item的點擊事件，但是這樣會破壞代碼的邏輯。
步驟
adapter中
自定義一個繼承自RecyclerView.Adapter的MyAdapter。
1.在MyAdapter中定義如下接口,模擬ListView的OnItemClickListener：
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//define interface public static interface OnRecyclerViewItemClickListener { void onItemClick(View view , String data); } |
聲明一個這個接口的變量
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private OnRecyclerViewItemClickListener mOnItemClickListener = null; |
在onCreateViewHolder()中爲每個item添加點擊事件
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@Override public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) { View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item, viewGroup, false); ViewHolder vh = new ViewHolder(view); //將創建的View註冊點擊事件 view.setOnClickListener(this); return vh; } |
將點擊事件轉移給外面的調用者：
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@Override public void onClick(View v) { if (mOnItemClickListener != null) { //注意這裏使用getTag方法獲取數據 mOnItemClickListener.onItemClick(v,(String)v.getTag()); } } |
注意上面調用接口的onItemClick()中的v.getTag()方法，這需要在onBindViewHolder()方法中設置和item相關的數據
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@Override public void onBindViewHolder(ViewHolder viewHolder, int position) { viewHolder.mTextView.setText(datas[position]); //將數據保存在itemView的Tag中，以便點擊時進行獲取 viewHolder.itemView.setTag(datas[position]); } |
最後暴露給外面的調用者，定義一個設置Listener的方法（）：
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public void setOnItemClickListener(OnRecyclerViewItemClickListener listener) { this.mOnItemClickListener = listener; } |
以上所有步驟都發生在自定義的adapter中，典型的觀察者模式，有點繞的地方在於，這裏涉及到兩個觀察者模式的使用，view的setOnClickListener本來就是觀察者模式，我們將這個觀察者模式的事件監聽傳遞給了我們自己的觀察者模式。
在Activity中使用
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mRecyclerView = (RecyclerView)findViewById(R.id.my_recycler_view); //創建默認的線性LayoutManager mLayoutManager = new LinearLayoutManager(this); mRecyclerView.setLayoutManager(mLayoutManager); //如果可以確定每個item的高度是固定的，設置這個選項可以提高性能 mRecyclerView.setHasFixedSize(true); //創建並設置Adapter mAdapter = new MyAdapter(data); mRecyclerView.setAdapter(mAdapter); mAdapter.setOnItemClickListener(new OnRecyclerViewItemClickListener(){ @Override public void onItemClick(View view , String data){ Toast.makeText(MainActivity.this, data, 600).show(); } }); |
完整代碼
MyAdapter.java
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package com.example.recyclerviewdemo;import android.support.v7.widget.RecyclerView;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> implements View.OnClickListener{ private String[] datas; public MyAdapter(String[] datas) { this.datas = datas; } private OnRecyclerViewItemClickListener mOnItemClickListener = null; //define interface public static interface OnRecyclerViewItemClickListener { void onItemClick(View view , String data); } @Override public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) { View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item, viewGroup, false); ViewHolder vh = new ViewHolder(view); //將創建的View註冊點擊事件 view.setOnClickListener(this); return vh; } @Override public void onBindViewHolder(ViewHolder viewHolder, int position) { viewHolder.mTextView.setText(datas[position]); //將數據保存在itemView的Tag中，以便點擊時進行獲取 viewHolder.itemView.setTag(datas[position]); } @Override public void onClick(View v) { if (mOnItemClickListener != null) { //注意這裏使用getTag方法獲取數據 mOnItemClickListener.onItemClick(v,(String)v.getTag()); } } public void setOnItemClickListener(OnRecyclerViewItemClickListener listener) { this.mOnItemClickListener = listener; } //獲取數據的數量 @Override public int getItemCount() { return datas.length; } //自定義的ViewHolder，持有每個Item的的所有界面元素 public static class ViewHolder extends RecyclerView.ViewHolder { public TextView mTextView; public ViewHolder(View view){ super(view); mTextView = (TextView) view.findViewById(R.id.text); } }} |
item.xml
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="50dip" > <TextView android:id="@+id/text" android:layout_width="wrap_content" android:layout_height="wrap_content" /></RelativeLayout> |
MainActivity.java
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package com.example.recyclerviewdemo;import com.example.recyclerviewdemo.MyAdapter.OnRecyclerViewItemClickListener;import android.support.v7.app.ActionBarActivity;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.Toast;public class MainActivity extends ActionBarActivity { private RecyclerView mRecyclerView; private LinearLayoutManager mLayoutManager; private MyAdapter mAdapter; private String[] data= new String[] {"aa","bb", "aa","bb", "aa","bb", "aa","bb", "aa","bb","aa","bb", "aa","bb", "aa","bb", "aa","bb", "aa","bb" }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mRecyclerView = (RecyclerView)findViewById(R.id.my_recycler_view); //創建默認的線性LayoutManager mLayoutManager = new LinearLayoutManager(this); mRecyclerView.setLayoutManager(mLayoutManager); //如果可以確定每個item的高度是固定的，設置這個選項可以提高性能 mRecyclerView.setHasFixedSize(true); //創建並設置Adapter mAdapter = new MyAdapter(data); mRecyclerView.setAdapter(mAdapter); mAdapter.setOnItemClickListener(new OnRecyclerViewItemClickListener(){ @Override public void onItemClick(View view , String data){ Toast.makeText(MainActivity.this, data, 600).show(); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.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(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } } |
activity_main.xml
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <android.support.v7.widget.RecyclerView android:id="@+id/my_recycler_view" android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars="vertical"/></RelativeLayout> |
總結
在ListView中我們是調用ListView的setOnItemClickListener：
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mListView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { ... } }); |
而在我們這裏是調用mAdapter的setOnItemClickListener。且回調方法public void onItemClick()的參數也不一致，ListView中有被點擊item的position參數，而我們這裏直接是被點擊item的相關數據（這裏只是一個字符串）。