Android 下拉刷新,上拉加载更多控件–支持ListView,GridView和ScrollView
文章出处：http://miloisbadboy.com/archives/55
麦洛遇到这样一个需求,实现类似于IOS下拉刷新,上拉加载更多的控件.麦洛google,baidu了一番,网上有不少实现,比较常见的是国外牛人的实现,不过国外的实现基本上都是扩展于ListView,所以,对于麦洛来说,还是有些局限性.后来发现国内的一些牛人开放的源码,不过,虽然有的是支持ListView和GridView,或者ScrollView,但都不是很通用,而且有的还不支持上拉加载.发现不大好用,于是麦洛决定自己开发一个同时支持这三个常用的滚动条控件.
麦洛研究了一番,花两三天的时间,这个过程可谓是焦头烂额啊.不过成果还是出来,在此公开一下,毕竟麦洛的大部分知识也是来源于他人的贡献.
麦洛的这个实现模仿了国外国内牛人的实现,也不知道名号,不过在此还是谢过了.
大概的原理是这样:扩展于LinearLayout,header(下拉显示出来的view)通过设置它的topMargin的值让它隐藏在最上边,而footer(上拉显示出来的view)直接添加addView(),只要ListView,GridView或ScrollView是Match_parent的,那么footer就会隐藏在最下方.当手指滚动时,就是不断的改变header 的topMargin的值,对于footer 也是一样的.所以,原理是很简单的.不过这样有一个小小的不好之处,麦洛暂时不说,谁发现谁留言吧.
具体类的实现如下:
package com.miloisbadboy.view;
import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.ScrollView;
import android.widget.TextView;
import com.miloisbadboy.R;
public class PullToRefreshView extends LinearLayout {
private static final String TAG = "PullToRefreshView";
// refresh states
private static final int PULL_TO_REFRESH = 2;
private static final int RELEASE_TO_REFRESH = 3;
private static final int REFRESHING = 4;
// pull state
private static final int PULL_UP_STATE = 0;
private static final int PULL_DOWN_STATE = 1;
/**
* last y
*/
private int mLastMotionY;
/**
* lock
*/
private boolean mLock;
/**
* header view
*/
private View mHeaderView;
/**
* footer view
*/
private View mFooterView;
/**
* list or grid
*/
private AdapterView< ?> mAdapterView;
/**
* scrollview
*/
private ScrollView mScrollView;
/**
* header view height
*/
private int mHeaderViewHeight;
/**
* footer view height
*/
private int mFooterViewHeight;
/**
* header view image
*/
private ImageView mHeaderImageView;
/**
* footer view image
*/
private ImageView mFooterImageView;
/**
* header tip text
*/
private TextView mHeaderTextView;
/**
* footer tip text
*/
private TextView mFooterTextView;
/**
* header refresh time
*/
private TextView mHeaderUpdateTextView;
/**
* footer refresh time
*/
// private TextView mFooterUpdateTextView;
/**
* header progress bar
*/
private ProgressBar mHeaderProgressBar;
/**
* footer progress bar
*/
private ProgressBar mFooterProgressBar;
/**
* layout inflater
*/
private LayoutInflater mInflater;
/**
* header view current state
*/
private int mHeaderState;
/**
* footer view current state
*/
private int mFooterState;
/**
* pull state,pull up or pull down;PULL_UP_STATE or PULL_DOWN_STATE
*/
private int mPullState;
/**
* 变为向下的箭头,改变箭头方向
*/
private RotateAnimation mFlipAnimation;
/**
* 变为逆向的箭头,旋转
*/
private RotateAnimation mReverseFlipAnimation;
/**
* footer refresh listener
*/
private OnFooterRefreshListener mOnFooterRefreshListener;
/**
* footer refresh listener
*/
private OnHeaderRefreshListener mOnHeaderRefreshListener;
/**
* last update time
*/
private String mLastUpdateTime;
public PullToRefreshView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public PullToRefreshView(Context context) {
super(context);
init();
}
/**
* init
*
* @description
* @param context
*/
private void init() {
// Load all of the animations we need in code rather than through XML
mFlipAnimation = new RotateAnimation(0, -180, RotateAnimation.RELATIVE_TO_SELF, 0.5f,
RotateAnimation.RELATIVE_TO_SELF, 0.5f);
mFlipAnimation.setInterpolator(new LinearInterpolator());
mFlipAnimation.setDuration(250);
mFlipAnimation.setFillAfter(true);
mReverseFlipAnimation = new RotateAnimation(-180, 0, RotateAnimation.RELATIVE_TO_SELF,
0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f);
mReverseFlipAnimation.setInterpolator(new LinearInterpolator());
mReverseFlipAnimation.setDuration(250);
mReverseFlipAnimation.setFillAfter(true);
mInflater = LayoutInflater.from(getContext());
// header view 在此添加,保证是第一个添加到linearlayout的最上端
addHeaderView();
}
private void addHeaderView() {
// header view
mHeaderView = mInflater.inflate(R.layout.refresh_header, this, false);
mHeaderImageView = (ImageView) mHeaderView.findViewById(R.id.pull_to_refresh_image);
mHeaderTextView = (TextView) mHeaderView.findViewById(R.id.pull_to_refresh_text);
mHeaderUpdateTextView = (TextView) mHeaderView
.findViewById(R.id.pull_to_refresh_updated_at);
mHeaderProgressBar = (ProgressBar) mHeaderView.findViewById(R.id.pull_to_refresh_progress);
// header layout
measureView(mHeaderView);
mHeaderViewHeight = mHeaderView.getMeasuredHeight();
LayoutParams params = new LayoutParams(LayoutParams.MATCH_PARENT, mHeaderViewHeight);
// 设置topMargin的值为负的header View高度,即将其隐藏在最上方
params.topMargin = -(mHeaderViewHeight);
// mHeaderView.setLayoutParams(params1);
addView(mHeaderView, params);
}
private void addFooterView() {
// footer view
mFooterView = mInflater.inflate(R.layout.refresh_footer, this, false);
mFooterImageView = (ImageView) mFooterView.findViewById(R.id.pull_to_load_image);
mFooterTextView = (TextView) mFooterView.findViewById(R.id.pull_to_load_text);
mFooterProgressBar = (ProgressBar) mFooterView.findViewById(R.id.pull_to_load_progress);
// footer layout
measureView(mFooterView);
mFooterViewHeight = mFooterView.getMeasuredHeight();
LayoutParams params = new LayoutParams(LayoutParams.MATCH_PARENT, mFooterViewHeight);
//int top = getHeight();
//params.topMargin =getHeight();//在这里getHeight()==0,但在onInterceptTouchEvent()方法里getHeight()已经有值了,不再是0;
// getHeight()什么时候会赋值,稍候再研究一下
// 由于是线性布局可以直接添加,只要AdapterView的高度是MATCH_PARENT,那么footer view就会被添加到最后,并隐藏
addView(mFooterView, params);
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
// footer view 在此添加保证添加到linearlayout中的最后
addFooterView();
initContentAdapterView();
}
/**
* init AdapterView like ListView,GridView and so on;or init ScrollView
*
*/
private void initContentAdapterView() {
int count = getChildCount();
if (count < 3) {
throw new IllegalArgumentException(
"this layout must contain 3 child views,and AdapterView or ScrollView must in the second position!");
}
View view = null;
for(int i=0;i) {
mAdapterView = (AdapterView< ?>) view;
}
if (view instanceof ScrollView) {
// finish later
mScrollView = (ScrollView)view;
}
}
if (mAdapterView == null && mScrollView==null) {
throw new IllegalArgumentException("must contain a AdapterView or ScrollView in this layout!");
}
}
private void measureView(View child) {
ViewGroup.LayoutParams p = child.getLayoutParams();
if (p == null) {
p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
}
int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent e) {
int y = (int) e.getRawY();
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
// 首先拦截down事件,记录y坐标
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
// deltaY > 0 是向下运动,< 0是向上运动
int deltaY = y - mLastMotionY;
if (isRefreshViewScroll(deltaY)) {
return true;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
break;
}
return false;
}
/*
* 如果在onInterceptTouchEvent()方法中没有拦截(即onInterceptTouchEvent()方法中 return
* false)则由PullToRefreshView 的子View来处理;否则由下面的方法来处理(即由PullToRefreshView自己来处理)
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mLock) {
return true;
}
int y = (int) event.getRawY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// onInterceptTouchEvent已经记录
// mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
int deltaY = y - mLastMotionY;
if (mPullState == PULL_DOWN_STATE) {
// PullToRefreshView执行下拉
Log.i(TAG, " pull down!parent view move!");
headerPrepareToRefresh(deltaY);
// setHeaderPadding(-mHeaderViewHeight);
} else if (mPullState == PULL_UP_STATE) {
// PullToRefreshView执行上拉
Log.i(TAG, "pull up!parent view move!");
footerPrepareToRefresh(deltaY);
}
mLastMotionY = y;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
int topMargin = getHeaderTopMargin();
if (mPullState == PULL_DOWN_STATE) {
if (topMargin >= 0) {
// 开始刷新
headerRefreshing();
} else {
// 还没有执行刷新，重新隐藏
setHeaderTopMargin(-mHeaderViewHeight);
}
} else if (mPullState == PULL_UP_STATE) {
if(Math.abs(topMargin)>=mHeaderViewHeight+mFooterViewHeight){
// 开始执行footer 刷新
footerRefreshing();
} else {
// 还没有执行刷新，重新隐藏
setHeaderTopMargin(-mHeaderViewHeight);
}
}
break;
}
return super.onTouchEvent(event);
}
/**
* 是否应该到了父View,即PullToRefreshView滑动
*
* @param deltaY
* , deltaY > 0 是向下运动,< 0是向上运动
* @return
*/
private boolean isRefreshViewScroll(int deltaY) {
if (mHeaderState == REFRESHING || mFooterState == REFRESHING) {
return false;
}
//对于ListView 以及GridView
if (mAdapterView != null) {
View child = mAdapterView.getChildAt(0);
if (child == null) {
// 如果mAdapterView中没有数据,不拦截
// 可以考虑返回true
return false;
}
// 子view(ListView or GridView)滑动到最顶端
if (deltaY > 0 && child.getTop() == 0) {
mPullState = PULL_DOWN_STATE;
return true;
} else if (deltaY < 0) {
View lastChild = mAdapterView.getChildAt(mAdapterView.getChildCount() - 1);
if (lastChild == null) {
// 如果mAdapterView中没有数据,不拦截
return false;
}
// 最后一个子view的Bottom小于父View的高度说明mAdapterView的数据没有填满父view,
// 等于父View的高度说明mAdapterView已经滑动到最后
if (lastChild.getBottom() <= getHeight()) {
mPullState = PULL_UP_STATE;
return true;
}
}
}
//对于ScrollView
if(mScrollView!=null){
// 子scroll view滑动到最顶端
View child = mScrollView.getChildAt(0);
if (deltaY > 0 && mScrollView.getScrollY() == 0) {
mPullState = PULL_DOWN_STATE;
return true;
} else if (deltaY < 0 && child.getMeasuredHeight()<=getHeight()+mScrollView.getScrollY()) {
mPullState = PULL_UP_STATE;
return true;
}
}
return false;
}
/**
* header 准备刷新,手指移动过程,还没有释放
*
* @param deltaY
* ,手指滑动的距离
*/
private void headerPrepareToRefresh(int deltaY) {
int newTopMargin = changingHeaderViewTopMargin(deltaY);
// 当header view的topMargin>=0时，说明已经完全显示出来了,修改header view 的提示状态
if (newTopMargin >= 0 && mHeaderState != RELEASE_TO_REFRESH) {
mHeaderTextView.setText(R.string.pull_to_refresh_release_label);
mHeaderUpdateTextView.setVisibility(View.VISIBLE);
mHeaderImageView.clearAnimation();
mHeaderImageView.startAnimation(mFlipAnimation);
mHeaderState = RELEASE_TO_REFRESH;
}
}
/**
* footer 准备刷新,手指移动过程,还没有释放 移动footer view高度同样和移动header view
* 高度是一样，都是通过修改header view的topmargin的值来达到
*
* @param deltaY
* ,手指滑动的距离
*/
private void footerPrepareToRefresh(int deltaY) {
int newTopMargin = changingHeaderViewTopMargin(deltaY);
//如果header view topMargin 的绝对值大于或等于header + footer 的高度
//说明footer view 完全显示出来了，修改footer view 的提示状态
if(Math.abs(newTopMargin)>=(mHeaderViewHeight+mFooterViewHeight)
&& mFooterState != RELEASE_TO_REFRESH){
mFooterTextView.setText(R.string.pull_to_refresh_footer_release_label);
mFooterImageView.clearAnimation();
mFooterImageView.startAnimation(mFlipAnimation);
mFooterState = RELEASE_TO_REFRESH;
}
}
/**
* 修改Header view top margin的值
* @description
* @param deltaY
* @return
*/
private int changingHeaderViewTopMargin(int deltaY){
LayoutParams params = (LayoutParams) mHeaderView.getLayoutParams();
float newTopMargin = params.topMargin + deltaY * 0.3f;
params.topMargin = (int) newTopMargin;
mHeaderView.setLayoutParams(params);
invalidate();
return params.topMargin;
}
/**
* header refreshing
*
*/
private void headerRefreshing() {
mHeaderState = REFRESHING;
setHeaderTopMargin(0);
mHeaderImageView.setVisibility(View.GONE);
mHeaderImageView.clearAnimation();
mHeaderImageView.setImageDrawable(null);
mHeaderProgressBar.setVisibility(View.VISIBLE);
mHeaderTextView.setText(R.string.pull_to_refresh_refreshing_label);
if (mOnHeaderRefreshListener != null) {
mOnHeaderRefreshListener.onHeaderRefresh(this);
}
}
/**
* footer refreshing
*
*/
private void footerRefreshing() {
mFooterState = REFRESHING;
int top = mHeaderViewHeight + mFooterViewHeight;
setHeaderTopMargin(-top);
mFooterImageView.setVisibility(View.GONE);
mFooterImageView.clearAnimation();
mFooterImageView.setImageDrawable(null);
mFooterProgressBar.setVisibility(View.VISIBLE);
mFooterTextView.setText(R.string.pull_to_refresh_footer_refreshing_label);
if (mOnFooterRefreshListener != null) {
mOnFooterRefreshListener.onFooterRefresh(this);
}
}
/**
* 设置header view 的topMargin的值
*
* @description
* @param topMargin
* ，为0时，说明header view 刚好完全显示出来； 为-mHeaderViewHeight时，说明完全隐藏了
*/
private void setHeaderTopMargin(int topMargin) {
LayoutParams params = (LayoutParams) mHeaderView.getLayoutParams();
params.topMargin = topMargin;
mHeaderView.setLayoutParams(params);
invalidate();
}
/**
* header view 完成更新后恢复初始状态
*
*/
public void onHeaderRefreshComplete() {
setHeaderTopMargin(-mHeaderViewHeight);
mHeaderImageView.setVisibility(View.VISIBLE);
mHeaderImageView.setImageResource(R.drawable.ic_pulltorefresh_arrow);
mHeaderTextView.setText(R.string.pull_to_refresh_pull_label);
mHeaderProgressBar.setVisibility(View.GONE);
// mHeaderUpdateTextView.setText("");
mHeaderState = PULL_TO_REFRESH;
}
/**
* Resets the list to a normal state after a refresh.
* @param lastUpdated Last updated at.
*/
public void onHeaderRefreshComplete(CharSequence lastUpdated) {
setLastUpdated(lastUpdated);
onHeaderRefreshComplete();
}
/**
* footer view 完成更新后恢复初始状态
*/
public void onFooterRefreshComplete() {
setHeaderTopMargin(-mHeaderViewHeight);
mFooterImageView.setVisibility(View.VISIBLE);
mFooterImageView.setImageResource(R.drawable.ic_pulltorefresh_arrow_up);
mFooterTextView.setText(R.string.pull_to_refresh_footer_pull_label);
mFooterProgressBar.setVisibility(View.GONE);
// mHeaderUpdateTextView.setText("");
mFooterState = PULL_TO_REFRESH;
}
/**
* Set a text to represent when the list was last updated.
* @param lastUpdated Last updated at.
*/
public void setLastUpdated(CharSequence lastUpdated) {
if (lastUpdated != null) {
mHeaderUpdateTextView.setVisibility(View.VISIBLE);
mHeaderUpdateTextView.setText(lastUpdated);
} else {
mHeaderUpdateTextView.setVisibility(View.GONE);
}
}
/**
* 获取当前header view 的topMargin
*
* @description
*/
private int getHeaderTopMargin() {
LayoutParams params = (LayoutParams) mHeaderView.getLayoutParams();
return params.topMargin;
}
/**
* lock
*
*/
private void lock() {
mLock = true;
}
/**
* unlock
*
*/
private void unlock() {
mLock = false;
}
/**
* set headerRefreshListener
*
* @description
* @param headerRefreshListener
*/
public void setOnHeaderRefreshListener(OnHeaderRefreshListener headerRefreshListener) {
mOnHeaderRefreshListener = headerRefreshListener;
}
public void setOnFooterRefreshListener(OnFooterRefreshListener footerRefreshListener) {
mOnFooterRefreshListener = footerRefreshListener;
}
/**
* Interface definition for a callback to be invoked when list/grid footer
* view should be refreshed.
*/
public interface OnFooterRefreshListener {
public void onFooterRefresh(PullToRefreshView view);
}
/**
* Interface definition for a callback to be invoked when list/grid header
* view should be refreshed.
*/
public interface OnHeaderRefreshListener {
public void onHeaderRefresh(PullToRefreshView view);
}
}
需要注意的几个方法是:
@Override
public boolean onInterceptTouchEvent(MotionEvent e) {
int y = (int) e.getRawY();
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
// 首先拦截down事件,记录y坐标
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
// deltaY > 0 是向下运动,< 0是向上运动
int deltaY = y - mLastMotionY;
if (isRefreshViewScroll(deltaY)) {
return true;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
break;
}
return false;
}
在这个方法里对事件进行拦截,主要是体现在isReFreshViewScroll(deltaY)这个方法,当返回true时,说明由父View,即PullToRefreshView自己来处理,否则由其子View如ListView,GridView,和ScrollView来处理.
真正对上拉以及下拉的处理是在onTouchEvent(event)这个方法里:
/*
* 如果在onInterceptTouchEvent()方法中没有拦截(即onInterceptTouchEvent()方法中 return
* false)则由PullToRefreshView 的子View来处理;否则由下面的方法来处理(即由PullToRefreshView自己来处理)
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mLock) {
return true;
}
int y = (int) event.getRawY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// onInterceptTouchEvent已经记录
// mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
int deltaY = y - mLastMotionY;
if (mPullState == PULL_DOWN_STATE) {
// PullToRefreshView执行下拉
Log.i(TAG, " pull down!parent view move!");
headerPrepareToRefresh(deltaY);
// setHeaderPadding(-mHeaderViewHeight);
} else if (mPullState == PULL_UP_STATE) {
// PullToRefreshView执行上拉
Log.i(TAG, "pull up!parent view move!");
footerPrepareToRefresh(deltaY);
}
mLastMotionY = y;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
int topMargin = getHeaderTopMargin();
if (mPullState == PULL_DOWN_STATE) {
if (topMargin >= 0) {
// 开始刷新
headerRefreshing();
} else {
// 还没有执行刷新，重新隐藏
setHeaderTopMargin(-mHeaderViewHeight);
}
} else if (mPullState == PULL_UP_STATE) {
if(Math.abs(topMargin)>=mHeaderViewHeight+mFooterViewHeight){
// 开始执行footer 刷新
footerRefreshing();
} else {
// 还没有执行刷新，重新隐藏
setHeaderTopMargin(-mHeaderViewHeight);
}
}
break;
}
return super.onTouchEvent(event);
}
根据不同的mPullState对相应的上拉或下拉操作进行处理.
这个类麦洛写很详细了,有很多注释,应该不难理解的了.调试一下就更清楚了.
将需要上拉下拉刷新功能的ListView,GridView或ScrollView作为PullToRefreshView的子View,由于PullToRefreshView是继承于LinearLayout所以必须设置orientation属性,否则显示不正确
最后在Activity中的用法:
mPullToRefreshView.setOnHeaderRefreshListener(new OnHeaderRefreshListener() {
@Override
public void onHeaderRefresh(PullToRefreshView view) {
mPullToRefreshView.postDelayed(new Runnable() {
@Override
public void run() {
//mPullToRefreshView.onHeaderRefreshComplete("最近更新:07-31 15:21");
mPullToRefreshView.onHeaderRefreshComplete();
}
}, 2000);
}
});
mPullToRefreshView.setOnFooterRefreshListener(new OnFooterRefreshListener() {
@Override
public void onFooterRefresh(PullToRefreshView view) {
mPullToRefreshView.postDelayed(new Runnable() {
@Override
public void run() {
mPullToRefreshView.onFooterRefreshComplete();
}
}, 1000);
}
});
大功告成！