Android5.x新特性之RecyclerGridView

<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.support.v7.widget.RecyclerView
android:id="@+id/id_recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#44ff0000" >

<TextView
android:id="@+id/id_num"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_gravity="center"
android:gravity="center"
android:text="1" />

</FrameLayout>

</pre><pre name="code" class="html">  <style name="AppTheme" parent="AppBaseTheme">

<!-- All customizations that are NOT specific to a particular API-level can go here. -->
<item name="android:listDivider">@drawable/divider_bg</item>
</style>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
<size android:width="5dp" android:height="5dp"/>
<solid android:color="#ffffff"/>

</shape>

package com.example.demo;

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

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.ViewHolder;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MainActivity extends Activity {

private RecyclerView mRecyclerView;
private List<String> mDatas;
private HomeAdapter mAdapter;

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

initData();
mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);
mRecyclerView.setLayoutManager(new GridLayoutManager(this, 4));
mRecyclerView.setAdapter(mAdapter = new HomeAdapter());

/**
* 分割线
*/
mRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));
}

protected void initData() {
mDatas = new ArrayList<String>();
for (int i = 'A'; i < 'z'; i++) {
mDatas.add("" + (char) i);
}
}

class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder> {

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
MainActivity.this).inflate(R.layout.item_home, parent,
false));
return holder;
}

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.tv.setText(mDatas.get(position));
}

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

class MyViewHolder extends ViewHolder {

TextView tv;

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

}

package com.example.demo;

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.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.LayoutManager;
import android.support.v7.widget.RecyclerView.State;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.Log;
import android.view.View;

public class DividerGridItemDecoration extends RecyclerView.ItemDecoration {

private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
private Drawable mDivider;

public DividerGridItemDecoration(Context context) {
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
}

@Override
public void onDraw(Canvas c, RecyclerView parent, State state) {

drawHorizontal(c, parent);
drawVertical(c, parent);

}

public void drawHorizontal(Canvas c, RecyclerView parent) {
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.getLeft() - params.leftMargin;
final int right = child.getRight() + params.rightMargin
+ mDivider.getIntrinsicWidth();
final int top = child.getBottom() + params.bottomMargin;
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}

public void drawVertical(Canvas c, RecyclerView parent) {
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 top = child.getTop() - params.topMargin;
final int bottom = child.getBottom() + params.bottomMargin;
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicWidth();

mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}

/***************************************************/

// public void drawVertical(Canvas c, RecyclerView parent) {
// final int left = parent.getPaddingLeft();
// final int right = parent.getWidth() - parent.getPaddingRight();
// //得到条目的数量
// final int childCount = parent.getChildCount();
//
// for (int i = 0; i < childCount; i++) {
// //得到
// final View child = parent.getChildAt(i);
// 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) {
int spanCount = getSpanCount(parent);
int childCount = parent.getAdapter().getItemCount();
if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部
{
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
} else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边
{
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else {
outRect.set(0, 0, mDivider.getIntrinsicWidth(),
mDivider.getIntrinsicHeight());
}
}

private int getSpanCount(RecyclerView parent) {
// 列数
int spanCount = -1;
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {

spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
spanCount = ((StaggeredGridLayoutManager) layoutManager)
.getSpanCount();
}
return spanCount;
}

private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
int childCount) {
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
{
return true;
}
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
if (orientation == StaggeredGridLayoutManager.VERTICAL) {
if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
{
return true;
}
} else {
childCount = childCount - childCount % spanCount;
if (pos >= childCount)// 如果是最后一列，则不需要绘制右边
return true;
}
}
return false;
}

private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
int childCount) {
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
childCount = childCount - childCount % spanCount;
if (pos >= childCount)// 如果是最后一行，则不需要绘制底部
return true;
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
// StaggeredGridLayoutManager 且纵向滚动
if (orientation == StaggeredGridLayoutManager.VERTICAL) {
childCount = childCount - childCount % spanCount;
// 如果是最后一行，则不需要绘制底部
if (pos >= childCount)
return true;
} else
// StaggeredGridLayoutManager 且横向滚动
{
// 如果是最后一行，则不需要绘制底部
if ((pos + 1) % spanCount == 0) {
return true;
}
}
}
return false;
}

}