android开发(49) Android 下拉刷新的实现。使用 SwipeRefreshLayout 代替 pull-to-refesh

概述

  谷歌官方推出了SwipeRefreshLayout 来实现下拉刷新的效果。对比以前我们常用的 pull-to-refesh ,这个方案显得更加的简单方便。

关联项目引用(管理依赖)

  在你的 应用级别的 build.gradle  中添加如下:  

   compile 'com.android.support:appcompat-v7:23.0.0'
compile 'com.android.support:support-v4:23.0.0'

编写布局(Layout)

<LinearLayout 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:orientation="vertical"
tools:context=".MainActivity"> <android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/swipeRefreshLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"> <ListView
android:id="@+id/listview1"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.v4.widget.SwipeRefreshLayout>
</LinearLayout>

在代码中  添加监听器处理事件

  public void setOnRefreshListener(OnRefreshListener listener)
  

完整代码

package demo.vir56k.swiperefreshlayoutdemo;

import android.os.Handler;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView; import java.util.ArrayList;
import java.util.Arrays;
import java.util.List; public class MainActivity extends AppCompatActivity {
private static final int REFRESH_COMPLETE = 0X110;
private SwipeRefreshLayout mSwipeLayout;
private ListView mListView;
private ArrayAdapter<String> mAdapter;
private List<String> mDatas; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); mListView = (ListView) findViewById(R.id.listview1);
mSwipeLayout = (SwipeRefreshLayout) findViewById(R.id.swipeRefreshLayout1); mDatas = creatDataSource();
mSwipeLayout.setOnRefreshListener(mSwipeRefreshLayoutOnRefreshListener);
mSwipeLayout.setColorSchemeResources(android.R.color.holo_blue_bright, android.R.color.holo_green_light,
android.R.color.holo_orange_light, android.R.color.holo_red_light);
mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mDatas);
mListView.setAdapter(mAdapter);
} private List<String> creatDataSource() {
mDatas = new ArrayList<String>();
for (int i = 0; i < 5; i++) {
mDatas.add("item" + i);
}
return mDatas;
} SwipeRefreshLayout.OnRefreshListener mSwipeRefreshLayoutOnRefreshListener = new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
mHandler.sendEmptyMessageDelayed(REFRESH_COMPLETE, 2000);
}
}; private Handler mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case REFRESH_COMPLETE:
List<String> lst = new ArrayList<String>();
for (int i = mDatas.size() + 3; i > mDatas.size(); i--) {
lst.add("item -" + i);
}
mDatas.addAll(0, lst);
mAdapter.notifyDataSetChanged();
mSwipeLayout.setRefreshing(false);
break; }
} ;
};
}

至此完成。

补充:

其他情形,遇到"SwipeRefreshLayout 的子控件不 直接是个listview 等,是个普通 relativewlayout 怎么办?"

解决方法: 继承 SwipeRefreshLayout 重写 canChildScrollUp 方法

/*
* Copyright 2016, 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.
*/ package com.example.android.architecture.blueprints.todoapp.tasks; import android.content.Context;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.SwipeRefreshLayout;
import android.util.AttributeSet;
import android.view.View; /**
* Extends {@link SwipeRefreshLayout} to support non-direct descendant scrolling views.
* <p>
* {@link SwipeRefreshLayout} works as expected when a scroll view is a direct child: it triggers
* the refresh only when the view is on top. This class adds a way (@link #setScrollUpChild} to
* define which view controls this behavior.
*/
public class ScrollChildSwipeRefreshLayout extends SwipeRefreshLayout { private View mScrollUpChild; public ScrollChildSwipeRefreshLayout(Context context) {
super(context);
} public ScrollChildSwipeRefreshLayout(Context context, AttributeSet attrs) {
super(context, attrs);
} @Override
public boolean canChildScrollUp() {
if (mScrollUpChild != null) {
return ViewCompat.canScrollVertically(mScrollUpChild, -1);
}
return super.canChildScrollUp();
} public void setScrollUpChild(View view) {
mScrollUpChild = view;
}
}

  

  

  

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