不知道那些工作了好久的大神是怎樣堅持寫部落格的，我發現我完全沒時間寫啊！就算有時間寫，在路上想好要學些什麼結果一回到租房，直接就往床上躺了。今天在外面跑步發現年初立下要好好學習，抽時間出來寫部落格記錄下自己的學習，結果發現部落格上P都沒有，於是跑完步回來立馬擼了個demo。湊個數,不知道自己到底能否堅持下去，這年頭在創業公司呆也不是走也不是，哎！

直接上程式碼吧！

DividerItemDecoration 分割線核心類

package com.example.richard.myapplication;

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.v4.view.ViewCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
 * Created by richard on 2016/6/19.
 */
 

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private int orientation = LinearLayoutManager.VERTICAL;
    private Drawable mDivider;
    private int[] attrs = new int[]{android.R.attr.listDivider};

    public DividerItemDecoration(Context context, int orientation) {
        TypedArray typedArray = context.obtainStyledAttributes(attrs);
        mDivider = typedArray.getDrawable(0
 
);
        typedArray.recycle();
        setOrientation(orientation);
    }

    public DividerItemDecoration(Context context, int orientation, int resId){
        mDivider = context.getResources().getDrawable(resId);
        setOrientation(orientation);
    }

    public void setOrientation(int orientation) {
        if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) {
            throw new IllegalArgumentException("this orientation is error!");
        }
        this.orientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        if (orientation == LinearLayoutManager.VERTICAL) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }


    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        //先呼叫getItemOffsets獲取條目之間的間隙
        //獲得條目的偏移量(所有的條目都回呼叫一次該方法)
        if (orientation == LinearLayoutManager.VERTICAL) {//垂直的畫水平線
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else {
            //水平的畫垂直線
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }

    /**
     * 垂直方向 畫水平線
     *
     * @param c
     * @param parent
     */
    private void drawVertical(Canvas c, RecyclerView parent) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight(); //減去內邊距
        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            int top = child.getBottom() + params.bottomMargin + (int) ViewCompat.getTranslationY(child);//可能有外邊距 或 者有偏移的動畫
            int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }


    /**
     * 水平方向 畫垂直線
     *
     * @param c
     * @param parent
     */
    private void drawHorizontal(Canvas c, RecyclerView parent) {
        int top = parent.getPaddingTop();
        int bottom = parent.getHeight() - parent.getPaddingBottom(); //減去內邊距
        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            int left = child.getRight() + params.rightMargin + (int) ViewCompat.getTranslationX(child);//可能有外邊距 或 者有偏移的動畫
            int right = left + mDivider.getIntrinsicWidth();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }
}

adapter

package com.example.richard.myapplication;

import android.graphics.Color;
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 TestAdapter extends RecyclerView.Adapter<TestAdapter.MyViewHolder> {

    private List<String>  dataList;

    public TestAdapter(List<String> list) {
        this.dataList = list;
    }

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

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        holder.tv.setText(dataList.get(position));
        holder.tv.setBackgroundColor(Color.rgb((int)(Math.random() * 255),(int)(Math.random() * 255),(int)(Math.random() * 255)));
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false);
        return new MyViewHolder(view);
    }

    public static class MyViewHolder extends RecyclerView.ViewHolder{
        TextView tv;

        public MyViewHolder(View itemView) {
            super(itemView);
            tv = (TextView) itemView.findViewById(R.id.tv);
        }
    }


}

MainActivity:

package com.example.richard.myapplication;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Button;

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

public class MainActivity extends AppCompatActivity {

    private Button btn;
    private boolean isVertichal = true;
    private DividerItemDecoration itemDecoration;
    private RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btn = (Button) findViewById(R.id.btn);

        recyclerView = (RecyclerView) findViewById(R.id.recylerview);
        List<String> dataList = new ArrayList<>();
        for (int i = 0; i < 100; i++){
            dataList.add("編號: " + i);
        }

        TestAdapter adapter = new TestAdapter(dataList);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);
        itemDecoration = new DividerItemDecoration(this, LinearLayoutManager.VERTICAL);
        recyclerView.addItemDecoration(itemDecoration);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                recyclerView.removeItemDecoration(itemDecoration);
                if (isVertichal){
                    recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false));
                    itemDecoration = new DividerItemDecoration(MainActivity.this, LinearLayoutManager.HORIZONTAL, R.drawable.divider_item);
                    recyclerView.addItemDecoration(itemDecoration);
                }else{
                    recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
                    itemDecoration = new DividerItemDecoration(MainActivity.this, LinearLayoutManager.VERTICAL, R.drawable.divider_item);
                    recyclerView.addItemDecoration(itemDecoration);
                }

                isVertichal = !isVertichal;
            }
        });
    }
}

divider_item:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">

    <size android:width="2dp"
        android:height="2dp"/>

    <solid
        android:color="#ff0000"/>

</shape>

效果如下：

水平豎直的分割線就沒截圖了。PS：這年頭理想值錢？讓我很惆悵啊！感覺什麼都是假的，唯有自己身體好才是真的。