RecyclerView的简单瀑布流效果

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

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">

<ImageView
android:id="@+id/icon"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@mipmap/a"
android:scaleType="fitXY"/>

<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="@android:color/holo_orange_light"
android:gravity="center"
android:textSize="18sp"/>
</LinearLayout>

package com.example.administrator.recyclerview;

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.ImageView;
import android.widget.TextView;

import java.util.List;

/**
* Created by Administrator on 2016/10/10 0010.
*/

public class MyRecyclerAdapter extends RecyclerView.Adapter<MyRecyclerAdapter.MyViewHolder> {

private Context context;
private List<String> mList;

public MyRecyclerAdapter(Context context, List<String> mList) {
this.context = context;
this.mList = mList;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//        View mView = View.inflate(context, R.layout.item, null);
View mView = LayoutInflater.from(context).inflate(R.layout.item, parent, false);
MyViewHolder mMyViewHolder = new MyViewHolder(mView);

return mMyViewHolder;
}

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
final String str = mList.get(position);
holder.mTextView.setText(str);
holder.mTextView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mTextViewOnClickLisenter != null) {
mTextViewOnClickLisenter.textViewclick(str);
}
}
});

if (position%2==0){
holder.mImageView.setBackgroundResource(R.mipmap.e);
}else{
holder.mImageView.setBackgroundResource(R.mipmap.b);
}
}

@Override
public int getItemCount() {
return mList == null ? 0 : mList.size();
}

class MyViewHolder extends RecyclerView.ViewHolder {
private TextView mTextView;
private ImageView mImageView;

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

private TextViewOnClickLisenter mTextViewOnClickLisenter;

public void setTextViewOnClickLisenter(TextViewOnClickLisenter l) {
mTextViewOnClickLisenter = l;
}

public interface TextViewOnClickLisenter {
void textViewclick(String str);
}
}

package com.example.administrator.recyclerview;

/*
* 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);
}
}
}

package com.example.administrator.recyclerview;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity implements MyRecyclerAdapter.TextViewOnClickLisenter {

private RecyclerView mRecyclerView;
private ArrayList<String> mList;

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

private void initEvent() {
MyRecyclerAdapter myRecyclerAdapter = new MyRecyclerAdapter(this, mList);
mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
mRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));
mRecyclerView.setAdapter(myRecyclerAdapter);
myRecyclerAdapter.setTextViewOnClickLisenter(this);
}

private void initData() {
mList = new ArrayList<>();
for (int i = 0; i < 50; i++) {
mList.add("照片" + i);
}
}

private void initView() {
mRecyclerView = (RecyclerView) findViewById(R.id.rv);
}

@Override
public void textViewclick(String str) {
Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
}
}