RecycleView的基本用法

2019-11-09 16:13:29

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一、RecycleView是android中一個很重要的高級控件，可以實現GridView,ListView,瀑布流等效果，實現了布局與Item，數據之間的分離，通過一個小案例掌握RecycleView的基本用法。

二、案例實現 1、RecycleView實現ListView 編碼思路 1、導入庫點擊File->PRoject Structure ->Dependencies->選擇V7的recycleview. 2、定義MyAdapter繼承RecycleView.Adapter類，泛型為RecycleView.ViewHolder，實現ViewHolder 3、LayoutManager為LinearLayoutManager 4、秒變GridView、水平的GridView的只要修改LayoutManager為

case R.id.id_GridView: mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3)); break; case R.id.id_hor_GridView: mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(5, StaggeredGridLayoutManager.HORIZONTAL)); break;

1、MyAdapter類

package com.kuxiao.trian.recycleview;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;public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyHolder> { private Context mContext; private List<String> mData; private LayoutInflater mInflater; private MyAdapter.OnItemClickListener OnItemClickListener; public MyAdapter(Context mContext, List<String> mData) { this.mContext = mContext; this.mData = mData; this.mInflater = LayoutInflater.from(mContext); } @Override public MyAdapter.MyHolder onCreateViewHolder(ViewGroup parent, int viewType) { MyHolder holder = new MyHolder(mInflater.inflate(R.layout.item, parent, false)); return holder; } @Override public void onBindViewHolder(final MyHolder holder, final int position) { holder.mTextView.setText(mData.get(position)); setUpItemClickListener(holder); } protected void setUpItemClickListener(final MyHolder holder) { if (OnItemClickListener != null) { holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int layoutPosition = holder.getLayoutPosition(); OnItemClickListener.onItemClick(v, layoutPosition); } }); holder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { int layoutPosition = holder.getLayoutPosition(); OnItemClickListener.onItemLongClick(v,layoutPosition); return true; } }); } } public void setOnItemClickListener(MyAdapter.OnItemClickListener onItemClickListener) { this.OnItemClickListener = onItemClickListener; } /** * 增加一項 * * @param position */ public void addItem(int position) { mData.add(position,"insert one"); notifyItemInserted(position); } /** * 刪除某項 * * @param position */ public void deleteItem(int position) { mData.remove(position); notifyItemRemoved(position); } @Override public int getItemCount() { return mData.size(); } class MyHolder extends RecyclerView.ViewHolder { TextView mTextView; public MyHolder(View itemView) { super(itemView); mTextView = (TextView) itemView.findViewById(R.id.id_tv_item); } } public interface OnItemClickListener { void onItemClick(View view,int position); void onItemLongClick(View view,int position); }}

2、自定義分割線類（DividerItemDecoration類）

package com.kuxiao.trian.recycleview;/* * 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) { Log.v("recyclerview - itemdecoration", "onDraw()"); 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); } }}

3、MianActivity類

package com.kuxiao.trian.recycleview;import android.content.Intent;import android.support.v7.app.AppCompatActivity;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.Toast;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity { private RecyclerView mRecyclerView = null; private RecyclerView.LayoutManager mLayoutManager = null; private List<String> mData = null; private MyAdapter myAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initData(); initView(); } private void initData() { mData = new ArrayList<String>(); for (int i = 'A'; i < 'z'; i++) { mData.add((char) i + ""); } } private void initView() { mRecyclerView = (RecyclerView) findViewById(R.id.id_rv); //布局器 mLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false); /* //自定義分割線 RecyclerView.ItemDecoration IteDecoration = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST); mRecyclerView.addItemDecoration(IteDecoration);*/ myAdapter = new MyAdapter(this, mData); mRecyclerView.setAdapter(myAdapter); mRecyclerView.setLayoutManager(mLayoutManager); mRecyclerView.setItemAnimator(new DefaultItemAnimator()); myAdapter.setOnItemClickListener(new MyAdapter.OnItemClickListener() { @Override public void onItemClick(View view, int position) { Toast.makeText(MainActivity.this,"點擊位置為" + position,Toast.LENGTH_SHORT).show(); } @Override public void onItemLongClick(View view, int position) { Toast.makeText(MainActivity.this,"長按的位置為" + position,Toast.LENGTH_SHORT).show(); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.mian, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.id_listview: mRecyclerView.setLayoutManager(mLayoutManager); break; case R.id.id_add: myAdapter.addItem(2); break; case R.id.id_delete: myAdapter.deleteItem(2); break; case R.id.id_GridView: mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3)); break; case R.id.id_hor_GridView: mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(5, StaggeredGridLayoutManager.HORIZONTAL)); break; case R.id.id_stagger: Intent intent = new Intent(this,MainActivity1.class); startActivity(intent); break; case R.id.id_settring: break; } return super.onOptionsItemSelected(item); }}

3、瀑布流效果是改變每一個Item的高度

package com.kuxiao.trian.recycleview;import android.content.Context;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;import java.util.ArrayList;import java.util.List;public class MyAdapter1 extends MyAdapter { private Context mContext; private static final String TAG = "MyAdapter1"; private List<Integer> mHiegths; public MyAdapter1(Context mContext, List<String> mData) { super(mContext, mData); this.mContext = mContext; mHiegths = new ArrayList<Integer>(); for (int i = 0; i < mData.size(); i++){ mHiegths.add((int) (100 + Math.random()*300)); } } @Override public void onBindViewHolder(MyHolder holder, int position) { super.onBindViewHolder(holder,position); MyHolder myHolder = (MyHolder) holder; ViewGroup.LayoutParams lp = myHolder.itemView.getLayoutParams(); lp.height = mHiegths.get(position); myHolder.itemView.setLayoutParams(lp); // setUpItemClickListener(myHolder); }}

注意事項： 1、自定義分割線用的屬性為 android:listDivider去獲取Drawable.

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle"> <size android:height="4dp" /> <gradient android:centerColor="#ff0000ff" android:endColor="#ffff0000" android:startColor="#ff00ff00" android:type="linear" /></shape>

2、增加與刪除Item操作與BaseAdapter的區別的NotifyItemInserted() NotifyDataChange()

/**增加項 */ public void addItem(int position) { mData.add(position,"insert one"); notifyItemInserted(position); } /** * 刪除某項 * * @param position */ public void deleteItem(int position) { mData.remove(position); notifyItemRemoved(position); }

3、Item點擊與長按事件實現用接口回調

//回調接口 public interface OnItemClickListener { void onItemClick(View view,int position); void onItemLongClick(View view,int position); } //設置接口 public void setOnItemClickListener(MyAdapter.OnItemClickListener onItemClickListener) { this.OnItemClickListener = onItemClickListener; } //綁定 public void onBindViewHolder(final MyHolder holder, final int position) { holder.mTextView.setText(mData.get(position)); setUpItemClickListener(holder); } protected void setUpItemClickListener(final MyHolder holder) { if (OnItemClickListener != null) { holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int layoutPosition = holder.getLayoutPosition(); OnItemClickListener.onItemClick(v, layoutPosition); } }); holder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { int layoutPosition = holder.getLayoutPosition(); OnItemClickListener.onItemLongClick(v,layoutPosition); return true; } }); } }

使用代碼

myAdapter1.setOnItemClickListener(new MyAdapter.OnItemClickListener() { @Override public void onItemClick(View view, int position) { myAdapter1.addItem(position); } @Override public void onItemLongClick(View view, int position) { myAdapter1.deleteItem(position); } });

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