本文主要包括以下內(nèi)容

自定義實現(xiàn)pulltorefreshView

使用google官方SwipeRefreshLayout

下拉刷新大致原理

判斷當(dāng)前是否在最上面而且是向下滑的，如果是的話，則加載數(shù)據(jù)，并更新界面。

自定義實現(xiàn)pulltorefreshView

package com.jimstin.pulltorefreshviewdemo.view;import com.jimstin.pulltorefreshviewdemo.R;import android.content.Context; import android.content.SharedPreferences; import android.graphics.Canvas; import android.os.AsyncTask; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewTreeObserver; import android.view.ViewTreeObserver.OnPreDrawListener; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.RelativeLayout; import android.widget.ScrollView; import android.widget.TextView; import android.view.View.OnTouchListener; import android.view.animation.Animation; import android.view.animation.Animation.AnimationListener; import android.view.animation.LinearInterpolator; import android.view.animation.RotateAnimation;public class PullToRefreshView extends LinearLayout implements OnTouchListener {private static PullToRefreshView mPullToRefreshView;private static Context mContext;private AttributeSet mAttrs;private View[] childs;private RelativeLayout mTopView, mBottomView;private MyScrollView mScrollView;private LinearLayout mContentView;private LayoutParams mParams;private static TextView mTopTips, mBottomTips;private static ImageView mTopTipsIcon, mBottomTipsIcon;private RotateAnimation toAnmt, backAnmt, progressBarAnmt;private boolean isToTop, isToBottom;private boolean isGetChilds;private boolean isRecordY;private boolean isContentNotFull;private boolean isResetLayoutParams;private boolean isActviteScrollEvent;//偏移量達(dá)到刷新或加載更多的要求時，為true，否則為falseprivate boolean isTurnUp;//判斷手勢，向上時為true，向下為falseprivate static boolean isRefresing;//是否正在刷新private static boolean isRefreshed = true;//是否已刷新完畢private static boolean isLoading;//是否正在加載private static boolean isLoaded = true;//是否已加載完畢private static boolean isPulling;//是否正在拖動scrollviewprivate boolean isRotate;//是否已經(jīng)動畫private static int topViewHeight;//topview的高度，和bottomview高度一致private int mHeight;//整個PullToRefreshView的高度private int scrollToEnd;//scrollview滾動到底部的長度private float lastY;//private float guestureLastY;//用于記錄手勢按下屏幕時的第一個位置private OnRefreshListener mRefreshListener;private OnLoadListener mLoadListener;public PullToRefreshView(Context context, AttributeSet attrs) {super(context, attrs);mContext = context;this.mAttrs = attrs;initView();}private void initView() {mPullToRefreshView = this;toAnmt = new RotateAnimation(0, 180f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);toAnmt.setDuration(300);toAnmt.setFillAfter(true);backAnmt = new RotateAnimation(0, -180f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);backAnmt.setDuration(300);backAnmt.setFillAfter(true);progressBarAnmt = new RotateAnimation(0, 360f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);progressBarAnmt.setDuration(1800);progressBarAnmt.setRepeatCount(-1);progressBarAnmt.setRepeatMode(RotateAnimation.RESTART);progressBarAnmt.setInterpolator(new LinearInterpolator());toAnmt.setAnimationListener(new AnimationListener() {@Overridepublic void onAnimationStart(Animation animation) {// TODO Auto-generated method stub}@Overridepublic void onAnimationRepeat(Animation animation) {// TODO Auto-generated method stub}@Overridepublic void onAnimationEnd(Animation animation) {// TODO Auto-generated method stubmTopTipsIcon.clearAnimation();mTopTipsIcon.setBackgroundResource(R.drawable.ic_up);mBottomTipsIcon.clearAnimation();mBottomTipsIcon.setBackgroundResource(R.drawable.ic_up);}});backAnmt.setAnimationListener(new AnimationListener() {@Overridepublic void onAnimationStart(Animation animation) {// TODO Auto-generated method stub}@Overridepublic void onAnimationRepeat(Animation animation) {// TODO Auto-generated method stub}@Overridepublic void onAnimationEnd(Animation animation) {// TODO Auto-generated method stubmTopTipsIcon.clearAnimation();mTopTipsIcon.setBackgroundResource(R.drawable.ic_down);mBottomTipsIcon.clearAnimation();mBottomTipsIcon.setBackgroundResource(R.drawable.ic_down);}});ViewTreeObserver ob = getViewTreeObserver();ob.addOnPreDrawListener(new OnPreDrawListener() {@Overridepublic boolean onPreDraw() {if(topViewHeight == 0 || mHeight == 0) {if(topViewHeight == 0) {topViewHeight = mTopView.getHeight();}if(mHeight == 0) {mHeight = getHeight();}if(mHeight > 0 && topViewHeight > 0) {SharedPreferences p = mContext.getSharedPreferences("PullToRefreshView", 0);p.edit().putInt("barHeight", topViewHeight).putInt("height", mHeight).commit();}mParams = new LayoutParams(LayoutParams.MATCH_PARENT, mHeight+2*topViewHeight);setLayoutParams(mParams);setY(-topViewHeight);}return true;}});}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {// TODO Auto-generated method stubsuper.onMeasure(widthMeasureSpec, heightMeasureSpec);}@Overrideprotected void onFinishInflate() {// TODO Auto-generated method stubsuper.onFinishInflate();setLayout();}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {super.onLayout(changed, l, t, r, b);}public void setLayout() {if(!isGetChilds) {int count = getChildCount();childs = new View[count];for(int i=0; i<count; i++) {childs[i] = getChildAt(i);}for(int i=0; i<count; i++) {removeAllViews();}LayoutInflater inflater = LayoutInflater.from(mContext);mTopView = (RelativeLayout) inflater.inflate(R.layout.layout_top_pull_to_refresh_view, null);mBottomView = (RelativeLayout) inflater.inflate(R.layout.layout_bottom_pull_to_refresh_view, null);mTopTips = (TextView) mTopView.findViewById(R.id.top_tips);mBottomTips = (TextView) mBottomView.findViewById(R.id.bottom_tips);mTopTipsIcon = (ImageView) mTopView.findViewById(R.id.ic_down);mBottomTipsIcon = (ImageView) mBottomView.findViewById(R.id.ic_up);mScrollView = new MyScrollView(mContext, mAttrs);mParams = new LayoutParams(LayoutParams.MATCH_PARENT, 0);mParams.weight = 1;mScrollView.setLayoutParams(mParams);mContentView = new LinearLayout(mContext, mAttrs);mContentView.setLayoutParams(mParams);mContentView.setOrientation(LinearLayout.VERTICAL);for(int i=0; i<count; i++) {mContentView.addView(childs[i]);}mScrollView.addView(mContentView);mScrollView.setOnTouchListener(this);addView(mTopView);addView(mScrollView);addView(mBottomView);isGetChilds = true;}}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);if(mScrollView.getHeight() > mContentView.getHeight()) {isContentNotFull = true;mBottomView.setVisibility(View.GONE);} else {isContentNotFull = false;}}/*** 設(shè)置刷新監(jiān)聽器*/public void setOnRefreshListener(OnRefreshListener listener) {mRefreshListener = listener;}/*** 設(shè)置加載監(jiān)聽器*/public void setOnLoadListener(OnLoadListener listener) {mLoadListener = listener;}class MyScrollView extends ScrollView {public MyScrollView(Context context, AttributeSet attrs) {super(context, attrs);}@Overrideprotected void onScrollChanged(int l, int t, int oldl, int oldt) {super.onScrollChanged(l, t, oldl, oldt);//MyLog.i("t="+t);if(t == 0) {isToTop = true;} else {if(t == getChildAt(0).getHeight()-getHeight()) {scrollToEnd = t;isToBottom = true;}}}}/*** 刷新監(jiān)聽器*/public static abstract class OnRefreshListener {/*** 正在刷新*/public void onRefresh() {}/*** 停止刷新，刷新完畢時請主動調(diào)用*/public void stopRefresh() {isRefresing = false;mTopTips.setText(mContext.getResources().getString(R.string.refreshed));mTopTipsIcon.clearAnimation();mTopTipsIcon.setBackgroundResource(R.drawable.ic_finish);resetYOffset();}}/*** 加載更多監(jiān)聽器**/public static abstract class OnLoadListener {/*** 正在加載*/public void onLoad() {}/*** 停止加載，加載完畢時請主動調(diào)用*/public void stopLoad() {isLoading = false;mBottomTips.setText(mContext.getResources().getString(R.string.loaded));mBottomTipsIcon.clearAnimation();mBottomTipsIcon.setBackgroundResource(R.drawable.ic_finish);resetYOffset();}}public static void resetYOffset() {new AsyncTask<Integer, Integer, Integer>() {@Overrideprotected Integer doInBackground(Integer... params) {try {Thread.sleep(1000);} catch (Exception e) {e.printStackTrace();}return null;}protected void onPostExecute(Integer result) {if(!isPulling) {mPullToRefreshView.setY(-topViewHeight);mTopTipsIcon.setBackgroundResource(R.drawable.ic_down);mBottomTipsIcon.setBackgroundResource(R.drawable.ic_up);isRefreshed = true;isLoaded = true;}};}.execute();}@Overridepublic boolean onTouch(View v, MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:guestureLastY = event.getRawY();isPulling = true;break;case MotionEvent.ACTION_MOVE:if(event.getRawY() - guestureLastY > 0) {isTurnUp = false;} else {isTurnUp = true;}if(isContentNotFull && !isResetLayoutParams) {mParams = new LayoutParams(LayoutParams.MATCH_PARENT, getHeight()-topViewHeight);setLayoutParams(mParams);isResetLayoutParams = true;}if(isToTop && !isTurnUp) {if(!isRecordY) {lastY = event.getRawY()/3;isRecordY = true;}mScrollView.setVerticalScrollBarEnabled(false);float y = 0.0f;if(!isRefreshed) {if(!isPulling) {y = event.getRawY()/3 - lastY - topViewHeight;} else {y = event.getRawY()/3 - lastY;}} else {y = event.getRawY()/3 - lastY - topViewHeight;}if(!isRefresing && isRefreshed) {if(Math.abs(event.getRawY()/3 - lastY) >= topViewHeight) {isActviteScrollEvent = true;mTopTips.setText(mContext.getResources().getString(R.string.release_to_refresh));if(!isRotate) {mTopTipsIcon.startAnimation(toAnmt);isRotate = true;}} else {isActviteScrollEvent = false;mTopTips.setText(mContext.getResources().getString(R.string.pull_to_refresh));if(isRotate) {mTopTipsIcon.startAnimation(backAnmt);isRotate = false;}}}setY(y);if(event.getRawY()/3 - lastY < 0) {isToTop = false;isRecordY = false;} else {mScrollView.setScrollY(0);}} else if(isToBottom || isContentNotFull) {if(!isRecordY) {lastY = event.getRawY()/3;isRecordY = true;}mScrollView.setVerticalScrollBarEnabled(false);if(!isLoading && isLoaded) {if(Math.abs(event.getRawY()/3 - lastY) >= topViewHeight) {isActviteScrollEvent = true;mBottomTips.setText(mContext.getResources().getString(R.string.release_to_load));if(!isRotate) {mBottomTipsIcon.startAnimation(backAnmt);isRotate = true;}} else {isActviteScrollEvent = false;mBottomTips.setText(mContext.getResources().getString(R.string.push_to_load));if(isRotate) {mBottomTipsIcon.startAnimation(toAnmt);isRotate = false;}}}float y = 0.0f;if(!isLoaded) {if(isPulling) {y = event.getRawY()/3 - lastY - 2*topViewHeight;} else {y = event.getRawY()/3 - lastY - topViewHeight;}} else {y = event.getRawY()/3 - lastY - topViewHeight;}setY(y);if(event.getRawY()/3 - lastY > 0) {isToBottom = false;isRecordY = false;} else {mScrollView.setScrollY(scrollToEnd);}}break;case MotionEvent.ACTION_UP:mScrollView.setVerticalScrollBarEnabled(true);isRotate = false;isRecordY = false;isPulling = false;if(isActviteScrollEvent) {if(isToTop && !isTurnUp) {if(mRefreshListener != null) {isRefresing = true;isRefreshed = false;setY(0);mTopTips.setText(mContext.getResources().getString(R.string.refreshing));mTopTipsIcon.setBackgroundResource(R.drawable.ic_refresh_progress_bar);mTopTipsIcon.startAnimation(progressBarAnmt);mRefreshListener.onRefresh();}} else if(isToBottom) {if(mLoadListener != null) {setY(-2*topViewHeight);mBottomTips.setText(mContext.getResources().getString(R.string.loading));mBottomTipsIcon.setBackgroundResource(R.drawable.ic_refresh_progress_bar);mBottomTipsIcon.startAnimation(progressBarAnmt);isLoading = true;isLoaded = false;mLoadListener.onLoad();}} else if(isContentNotFull) {setY(-topViewHeight);}isActviteScrollEvent = false;} else {if(isRefresing) {setY(0);} else if(isLoading) {setY(-2*topViewHeight);} else {setY(-topViewHeight);}}if(!isRefresing) {isRefreshed = true;} if(!isLoading) {isLoaded = true;}isToTop = false;isToBottom = false;break;default:break;}return false;}public void initLayoutParams() {SharedPreferences p = mContext.getSharedPreferences("PullToRefreshView", 0);topViewHeight = p.getInt("barHeight", 0);mHeight = p.getInt("height", 0);if(mHeight > 0) {mParams = new LayoutParams(LayoutParams.MATCH_PARENT, mHeight+2*topViewHeight);setLayoutParams(mParams);setY(-topViewHeight);}} }

參考鏈接

PullToRefreshView下拉刷新上來加載更多，支持任何子view！ - zhangjm_123的專欄 - 博客頻道 - CSDN.NET

SwipeRefreshLayout 使用

布局文件

<?xml version="1.0" encoding="utf-8"?> <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:padding="8dp"android:background="#Ffffff"><android.support.v4.widget.SwipeRefreshLayout android:id="@+id/swipe_refresh_layout_caselist"android:layout_marginTop="4dp"android:layout_width="wrap_content"android:layout_height="wrap_content"><ListView android:id="@+id/list"android:scrollbars="none"android:layout_width="match_parent"android:layout_height="match_parent"android:dividerHeight="0dp"android:divider="#Ffffff"></ListView></android.support.v4.widget.SwipeRefreshLayout> </LinearLayout>

在Activity中使用

@Overrideprotected void setUpView() {if (mIsFirstCreated){onRefresh();}listView = $(R.id.list);swipeRefreshLayout=$(R.id.swipe_refresh_layout_caselist);//設(shè)置刷新時動畫的顏色，可以設(shè)置4個swipeRefreshLayout.setColorSchemeResources(android.R.color.holo_blue_light, android.R.color.holo_red_light, android.R.color.holo_orange_light, android.R.color.holo_green_light);swipeRefreshLayout.setOnRefreshListener(this);getData(); // BaseAdapter arrayAdapter = new ArrayAdapter(getActivity(),R.layout.item_list,R.id.name, // Arrays.asList("美食劵", "活動劵", "優(yōu)惠劵", "團(tuán)購劵", "外賣劵")); // listView.setAdapter(arrayAdapter);}@Overridepublic void onRefresh() {//tv.setText("正在刷新");// TODO Auto-generated method stubmIsFirstCreated = false;getData();}

使用的類要實現(xiàn)SwipeRefreshLayout.OnRefreshListener接口

并且在數(shù)據(jù)獲取成功后發(fā)送消息，設(shè)置swipeRefreshLayout.setRefreshing(false);

參考鏈接

Google自己的下拉刷新組件SwipeRefreshLayout - 李金堯 - 博客園

你還在用開源控件的下拉刷新嗎？你out了，試一試官方的下拉刷新SwipeRefreshLayout - 推酷

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