Android之初探RecyclerView

RecyclerView的出現是爲了取代ListView和GirdView，因爲其可以實現ListView和GirdView的效果，也可以拓展很多效果，而且RecyclerView也做了很多優化。

其使用方法是先通過設置佈局管理器來確定佈局，然後在通過適配器來將數據和試圖進行綁定。這裏我舉個類似於瀑布流的小例子。

項目地址：http://download.csdn.net/detail/l_vaule/9519118

package com.example.recycleviewtest;



/*
 * 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("tz", "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);
		}
	}

	/**
	 * 爲我們的Item預留空間  因爲我們的recyclerView默認item間是不留空間的
	 * @param outRect
	 * @param itemPosition
	 * @param parent
	 */
	@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);
		}
	}
}

package com.example.recycleviewtest;

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.DefaultItemAnimator;
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;

public class MainActivity extends ActionBarActivity {
	
	private RecyclerView recyclerView;
	private List<String> mData;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
		initData();
		initView();
	}
	
	private void initView() {
		//1,設置線性佈局容器
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        //2,設置gridView佈局容器
        // recyclerView.setLayoutManager(new GridLayoutManager(this,4));
        recyclerView.setAdapter(new MyAdapter(mData, this));
        //3,添加分割線  gitHub  DividerItemDecoration
       recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
  
	}

	private void initData() {
		mData = new ArrayList<>();
		for (int i = 0; i < 10; i++) {
			mData.add("I'm handsome");
		}
		
	}

	@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) {
			recyclerView.removeAllViews();
			recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
			recyclerView.setAdapter(new StaggerAdapter(this, mData));
			 //添加條目或者刪除條目的動畫 ----- 系統已經提供了默認的動畫  我們也可以自己寫  gitHub
	        recyclerView.setItemAnimator(new DefaultItemAnimator());
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
}

package com.example.recycleviewtest;

import java.util.List;

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;
 
/**
 * @author ctt:
 * @version 創建時間：2016年5月12日 
 * 類說明
 */
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>{

	private List<String> mData;
	private Context context;
	
	
	public MyAdapter(List<String> mData, Context context) {
		super();
		this.mData = mData;
		this.context = context;
	}

	@Override
	public int getItemCount() {
		// TODO Auto-generated method stub
		return mData.size();
	}

	@Override
	public void onBindViewHolder(ViewHolder arg0, int arg1) {
		arg0.textView.setText(mData.get(arg1));
	}

	@Override
	public ViewHolder onCreateViewHolder(ViewGroup arg0, int arg1) {
		View view = LayoutInflater.from(context).inflate(R.layout.layout_item, arg0,false);
		return new ViewHolder(view);
	}
	class ViewHolder extends RecyclerView.ViewHolder{
		TextView textView;
		public ViewHolder(View itemView) {
			super(itemView);
			textView = (TextView) itemView.findViewById(R.id.tv);
		}
		
	}

}

package com.example.recycleviewtest;


import java.util.ArrayList;
import java.util.List;

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;

/**
 * @author ctt: 
 * @version 創建時間：2016年5月12日 
 * 類說明 
 */
public class StaggerAdapter  extends RecyclerView.Adapter<StaggerAdapter.StgViewHolder>{
	private List<String> mDatas;
    private LayoutInflater inflater; 
    private List<Integer> mHeights;
    public StaggerAdapter(Context context,List<String> mDatas){
        this.mDatas = mDatas;
        this.inflater = LayoutInflater.from(context);
        mHeights = new ArrayList<Integer>();
        //隨機爲每一個item設置高度
        for(int i=0;i<mDatas.size();i++){
            mHeights.add((int)(100+Math.random()*300));
        }
    }

    @Override
    public StaggerAdapter.StgViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.layout_item,parent,false);
        return new StgViewHolder(view);
    }
    
    @Override
    public void onBindViewHolder(StgViewHolder arg0, int arg1) {
    	//設置每一個item隨機高度
    	ViewGroup.LayoutParams params = arg0.textView.getLayoutParams();
    	params.height = mHeights.get(arg1);
    	arg0.textView.setLayoutParams(params);
    	arg0.textView.setText(mDatas.get(arg1));
    }

  
    @Override
    public int getItemCount() {
        return mDatas.size();
    }

    /**
     *  listView :ViewHolder
     * 
     *  條目的佈局：base_item
     */

    class StgViewHolder extends RecyclerView.ViewHolder{
        TextView textView;
        public StgViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.tv);
        }
    }
}