说到下拉刷新,相信大家都不陌生,现在基本上每个项目都会用到。我们公司的项目一直都是使用SwipeRefreshLayout,官方的Material Design风格,好用少Bug。现在下拉刷新大概有下面几种实现方式:一种是直接包在ListView或者RecyclerView的头部,有的则是像SwipeRefreshLayout一样,包在视图的最外层,个人建议使用包在最外层的做法,可拓展性比较强。下面用包在最外层的方法实现京东和天猫的下拉刷新。
1.使用框架Android-Ultra-Pull-To-Refresh
https://github.com/liaohuqiu/android-Ultra-Pull-To-Refresh
大家有兴趣的可以去看一下这个下拉刷新框架,可拓展性非常强,兼容各种View的下拉刷新事件。
2.京东下拉刷新
先看看京东的下拉刷新动画:
从上图可以看出,就是一个动画,当然截图有点卡,首先,我们解压手机京东的app,得到上面的图片:
先看看头部刷新的布局怎么实现:
jd_refresh_header_view.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content"> <FrameLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_toLeftOf="@+id/layout_tx"> <ImageView android:id="@+id/iv_man" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/a2a" /> <ImageView android:id="@+id/iv_goods" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="right|center" android:src="@drawable/a29" /> </FrameLayout> <LinearLayout android:id="@+id/layout_tx" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:layout_marginLeft="5dp" android:gravity="center_vertical" android:orientation="vertical" android:padding="5dp"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="让购物更便捷" android:textSize="14sp" /> <TextView android:id="@+id/tv_remain" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="5dp" android:text="松开刷新" android:textSize="12sp" /> </LinearLayout> </RelativeLayout>
咱们再看看android-Ultra-Pull-To-Refresh这个框架:
package in.srain.cube.views.ptr; import in.srain.cube.views.ptr.indicator.PtrIndicator; /** * */ public interface PtrUIHandler { /** * When the content view has reached top and refresh has been completed, view will be reset. * * @param frame */ public void onUIReset(PtrFrameLayout frame); /** * prepare for loading * * @param frame */ public void onUIRefreshPrepare(PtrFrameLayout frame); /** * perform refreshing UI */ public void onUIRefreshBegin(PtrFrameLayout frame); /** * perform UI after refresh */ public void onUIRefreshComplete(PtrFrameLayout frame); public void onUIPositionChange(PtrFrameLayout frame, boolean isUnderTouch, byte status, PtrIndicator ptrIndicator); }
这是一个下拉刷新事件处理接口,包括准备刷新,开始刷新,刷新完成和刷新改变等事件的处理,直接上代码:
JdRefreshHeader.java
package com.jackie.pulltorefresh.jd; import android.content.Context; import android.graphics.drawable.AnimationDrawable; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.View; import android.widget.FrameLayout; import android.widget.ImageView; import android.widget.TextView; import com.jackie.pulltorefresh.R; import in.srain.cube.views.ptr.PtrFrameLayout; import in.srain.cube.views.ptr.PtrUIHandler; import in.srain.cube.views.ptr.indicator.PtrIndicator; /** * 下拉刷新HeaderView */ public class JdRefreshHeader extends FrameLayout implements PtrUIHandler { /** * 提醒文本 */ private TextView mTvRemind; /** * 快递员logo */ private ImageView mIvMan; /** * 商品logo */ private ImageView mIvGoods; /** * 状态识别 */ private int mState; /** * 重置 * 准备刷新 * 开始刷新 * 结束刷新 */ public static final int STATE_RESET = -1; public static final int STATE_PREPARE = 0; public static final int STATE_BEGIN = 1; public static final int STATE_FINISH = 2; public static final int MARGIN_RIGHT = 100; /** * 动画 */ private AnimationDrawable mAnimationDrawable; public JdRefreshHeader(Context context) { this(context, null); } public JdRefreshHeader(Context context, AttributeSet attrs) { this(context, attrs, 0); } public JdRefreshHeader(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initView(); } /** * 初始化view */ private void initView() { View view = LayoutInflater.from(getContext()).inflate(R.layout.jd_refresh_header_view, this, false); mTvRemind = (TextView) view.findViewById(R.id.tv_remain); mIvMan = (ImageView) view.findViewById(R.id.iv_man); mIvGoods = (ImageView) view.findViewById(R.id.iv_goods); addView(view); } @Override public void onUIReset(PtrFrameLayout frame) { mState = STATE_RESET; } @Override public void onUIRefreshPrepare(PtrFrameLayout frame) { mState = STATE_PREPARE; } @Override public void onUIRefreshBegin(PtrFrameLayout frame) { mState = STATE_BEGIN; //隐藏商品logo,开启跑步动画 mIvGoods.setVisibility(View.GONE); mIvMan.setBackgroundResource(R.drawable.runningman); mAnimationDrawable = (AnimationDrawable) mIvMan.getBackground(); if (!mAnimationDrawable.isRunning()) { mAnimationDrawable.start(); } } @Override public void onUIRefreshComplete(PtrFrameLayout frame) { mState = STATE_FINISH; mIvGoods.setVisibility(View.VISIBLE); //停止动画 if (mAnimationDrawable.isRunning()) { mAnimationDrawable.stop(); } mIvMan.setBackgroundResource(R.drawable.a2a); } @Override public void onUIPositionChange(PtrFrameLayout frame, boolean isUnderTouch, byte status, PtrIndicator ptrIndicator) { //处理提醒字体 switch (mState) { case STATE_PREPARE: //logo设置 mIvMan.setAlpha(ptrIndicator.getCurrentPercent()); mIvGoods.setAlpha(ptrIndicator.getCurrentPercent()); LayoutParams params = (LayoutParams) mIvMan.getLayoutParams(); if (ptrIndicator.getCurrentPercent() <= 1) { mIvMan.setScaleX(ptrIndicator.getCurrentPercent()); mIvMan.setScaleY(ptrIndicator.getCurrentPercent()); mIvGoods.setScaleX(ptrIndicator.getCurrentPercent()); mIvGoods.setScaleY(ptrIndicator.getCurrentPercent()); int marginRight = (int) (MARGIN_RIGHT - MARGIN_RIGHT * ptrIndicator.getCurrentPercent()); params.setMargins(0, 0, marginRight, 0); mIvMan.setLayoutParams(params); } if (ptrIndicator.getCurrentPercent() < 1.2) { mTvRemind.setText("下拉刷新..."); } else { mTvRemind.setText("松开刷新..."); } break; case STATE_BEGIN: mTvRemind.setText("更新中..."); break; case STATE_FINISH: mTvRemind.setText("加载完成..."); break; } } }
创建一个成员变量mState,用于保存下拉刷新的时候,每一个状态,然后根据保存好的状态在UIPositionChange的接口中,对UI进行相应的修改,保存每个状态文本的提示,在下拉的过程中,通过UIPositionChange的回调,获取PtrIndicator中,可以获取下拉的百分比,根据这个百分比我们可以做很多东西,例如京东的快递小哥从远处跑过来拿商品,以及快递小哥与商品之间的大小,都可以根据这个PtrIndicator百分比进行设置其大小的比例,跑过来这个过程我使用的方法是利用marginRight进行设置两者之间的距离,当达到下拉刷新的临界点时,快递小哥跟商品之间的margin为0,达到了快递小哥获取商品的效果,然后当刷新的时候,隐藏商品,使用之前所提供的三张图片进行效应的切换,也就是动画:
<?xml version="1.0" encoding="utf-8"?> <animation-list xmlns:android="http://schemas.android.com/apk/res/android" android:oneshot="false"> <item android:drawable="@drawable/a2b" android:duration="70" /> <item android:drawable="@drawable/a2c" android:duration="70" /> <item android:drawable="@drawable/a2d" android:duration="70" /> </animation-list>
效果图如下:
3.天猫下拉刷新
天猫的更简单,毫无动画可言,说白了就是个GIF,大家可以去下载个apk,解压后能得到其gif。原理跟之前的是一样,但这里我使用的是fresco进行加载gif,方法有很多,大家感兴趣的可以去试试。
TmallRefreshHeader.java
package com.jackie.pulltorefresh.tmall; import android.content.Context; import android.net.Uri; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.View; import android.widget.FrameLayout; import android.widget.TextView; import com.facebook.drawee.backends.pipeline.Fresco; import com.facebook.drawee.interfaces.DraweeController; import com.facebook.drawee.view.SimpleDraweeView; import com.jackie.pulltorefresh.R; import in.srain.cube.views.ptr.PtrFrameLayout; import in.srain.cube.views.ptr.PtrUIHandler; import in.srain.cube.views.ptr.indicator.PtrIndicator; /** * 下拉刷新HeaderView */ public class TmallRefreshHeader extends FrameLayout implements PtrUIHandler { /** * 提醒文本 */ private TextView mTvRemind; /** * 状态识别 */ private int mState; /** * 重置 * 准备刷新 * 开始刷新 * 结束刷新 */ public static final int STATE_RESET = -1; public static final int STATE_PREPARE = 0; public static final int STATE_BEGIN = 1; public static final int STATE_FINISH = 2; public TmallRefreshHeader(Context context) { this(context, null); } public TmallRefreshHeader(Context context, AttributeSet attrs) { this(context, attrs, 0); } public TmallRefreshHeader(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initView(); } /** * 初始化view */ private void initView() { View view = LayoutInflater.from(getContext()).inflate(R.layout.tmall_refresh_header_view, this, false); mTvRemind = (TextView) view.findViewById(R.id.tv_remind); SimpleDraweeView sdv = (SimpleDraweeView) view.findViewById(R.id.tm_logo); DraweeController draweeController = Fresco.newDraweeControllerBuilder() .setAutoPlayAnimations(true) //设置uri,加载本地的gif资源 .setUri(Uri.parse("res://" + getContext().getPackageName() + "/" + R.drawable.tm_mui_bike))//设置uri .build(); sdv.setController(draweeController); addView(view); } @Override public void onUIReset(PtrFrameLayout frame) { mState = STATE_RESET; } @Override public void onUIRefreshPrepare(PtrFrameLayout frame) { mState = STATE_PREPARE; } @Override public void onUIRefreshBegin(PtrFrameLayout frame) { mState = STATE_BEGIN; } @Override public void onUIRefreshComplete(PtrFrameLayout frame) { mState = STATE_FINISH; } @Override public void onUIPositionChange(PtrFrameLayout frame, boolean isUnderTouch, byte status, PtrIndicator ptrIndicator) { //处理提醒字体 switch (mState) { case STATE_PREPARE: if (ptrIndicator.getCurrentPercent() < 1) { mTvRemind.setText("下拉刷新"); } else { mTvRemind.setText("松开立即刷新"); } break; case STATE_BEGIN: mTvRemind.setText("正在刷新..."); break; case STATE_FINISH: mTvRemind.setText("加载完成..."); break; } } }
效果图如下:
最后附上github地址:
https://github.com/shineflower/JdTmallPullToRefresh
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持呐喊教程。
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