說到下拉刷新控件，網(wǎng)上版本有很多，很多軟件也都有下拉刷新功能。有一個(gè)叫XListView的，我看別人用過，沒看過是咋實(shí)現(xiàn)的，看這名字估計(jì)是繼承自ListView修改的，不過效果看起來挺丑的，也沒什么擴(kuò)展性，太單調(diào)了。看了QQ2014的列表下拉刷新，發(fā)現(xiàn)挺好看的，我喜歡，貼一下圖看一下qq的下拉刷新效果：
不錯(cuò)吧？嗯，是的。一看就知道實(shí)現(xiàn)方式不一樣。咱們今天就來實(shí)現(xiàn)一個(gè)下拉刷新控件。由于有時(shí)候不僅僅是ListView需要下拉刷新，ExpandableListView和GridView也有這個(gè)需求，由于ListView，GridView都是AbsListView的子類，ExpandableListView是ListView的子類所以也是AbsListView的子類。所以我的思路是自定義一個(gè)對(duì)所有AbsListView的子類通用的下拉管理布局，叫PullToRefreshLayout，如果需要GridView，只需要在布局文件里將ListView換成GridView就行了，ExpandableListView也一樣，不需要再繼承什么GridView啊ListView啊亂七八糟的。
看上圖，主要工作就是定義黑色大布局，紅色部分是不下拉的時(shí)候的可見部分，可以是任意的AbsListView的子類（GridView，ListView，ExpandableListView等等）。其實(shí)我已經(jīng)寫好了，先看一下效果圖：
正常拉法：
強(qiáng)迫癥拉法：
上面是ListView的，下面是GridView的
再來看一下ExpandableListView的下拉刷新效果：
可以看到，點(diǎn)擊事件和長(zhǎng)按事件都能正常觸發(fā)而不會(huì)誤觸發(fā)，在使用ExpandableListView的時(shí)候需要注意禁止展開時(shí)自動(dòng)滾動(dòng)，否則會(huì)出現(xiàn)bug。后面會(huì)提供demo源碼下載，可以根據(jù)自己的需求去修改。
下面講解PullToRefreshLayout的實(shí)現(xiàn)，在貼完整的源碼之前先理解整個(gè)類的大概思路：
public class PullToRefreshLayout extends RelativeLayout implements OnTouchListener { // 下拉的距離 public float moveDeltaY = 0; // 是否可以下拉 private boolean canPull = true; private void hideHead() { // 在這里開始異步隱藏下拉頭，在松手的時(shí)候或這刷新完畢的時(shí)候隱藏 } public void refreshFinish(int refreshResult) { // 完成刷新操作，顯示刷新結(jié)果 } private void changeState(int to) { // 改變當(dāng)前所處的狀態(tài)，有四個(gè)狀態(tài)：下拉刷新、釋放刷新、正在刷新、刷新完成 } /* * （非 Javadoc）由父控件決定是否分發(fā)事件，防止事件沖突 * * @see android.view.ViewGroup#dispatchTouchEvent(android.view.MotionEvent) */ @Override public boolean dispatchTouchEvent(MotionEvent ev) { switch (ev.getActionMasked()) { case MotionEvent.ACTION_DOWN: /*手指按下的時(shí)候，無法判斷是否將要下拉，所以這時(shí)候break讓父類把down事件分發(fā)給子View 記錄按下的坐標(biāo)*/ break; case MotionEvent.ACTION_MOVE: /*如果往上滑動(dòng)且moveDetaY==0則說明不在下拉，break繼續(xù)將move事件分發(fā)給子View 如果往下拉，則計(jì)算下拉的距離moveDeltaY，根據(jù)moveDeltaY重新Layout子控件。但是 由于down事件傳到了子View，如果不清除子View的事件，會(huì)導(dǎo)致子View誤觸發(fā)長(zhǎng)按事件和點(diǎn)擊事件。所以在這里清除子View的事件回調(diào)。 下拉超過一定的距離時(shí)，改變當(dāng)前狀態(tài)*/ break; case MotionEvent.ACTION_UP: //根據(jù)當(dāng)前狀態(tài)執(zhí)行刷新操作或者h(yuǎn)ideHead default: break; } // 事件分發(fā)交給父類 return super.dispatchTouchEvent(ev); } /* * （非 Javadoc）繪制陰影效果，顏色值可以修改 * * @see android.view.ViewGroup#dispatchDraw(android.graphics.Canvas) */ @Override protected void dispatchDraw(Canvas canvas) { //在這里用一個(gè)漸變繪制分界線陰影 } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { //這個(gè)方法就是重新Layout子View了，根據(jù)moveDeltaY來定位子View的位置 } @Override public boolean onTouch(View v, MotionEvent event) { //這個(gè)是OnTouchListener的方法，只判斷AbsListView的狀態(tài)來決定是否canPull，除此之外不做其他處理 } } 可以看到，這里復(fù)寫了ViewGroup的dispatchTouchEvent，這樣就可以掌控事件的分發(fā)，如果不了解這個(gè)方法可以看一下這篇Android事件分發(fā)、View事件Listener全解析。之所以要控制事件分發(fā)是因?yàn)槲覀儾豢赡苤朗种竏own在AbsListView上之后將往上滑還是往下拉，所以down事件會(huì)分發(fā)給AbsListView的，但是在move的時(shí)候就需要看情況了，因?yàn)槲覀儾幌朐谙吕耐瑫r(shí)AbsListView也在滑動(dòng)，所以在下拉的時(shí)候不分發(fā)move事件，但這樣問題又來了，前面AbsListView已經(jīng)接收了down事件，如果這時(shí)候不分發(fā)move事件給它，它會(huì)觸發(fā)長(zhǎng)按事件或者點(diǎn)擊事件，所以在這里還需要清除AbsListView消息列表中的callback。
onLayout用于重新布置下拉頭和AbsListView的位置的，這個(gè)不難理解。
理解了大概思路之后，看一下PullToRefreshLayout完整的源碼吧~
package com.jingchen.pulltorefresh; import java.lang.reflect.Field; import java.util.Timer; import java.util.TimerTask; import android.content.Context; import android.graphics.Canvas; import android.graphics.LinearGradient; import android.graphics.Paint; import android.graphics.Paint.Style; import android.graphics.RectF; import android.graphics.Shader.TileMode; import android.os.Handler; import android.os.Message; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.view.ViewGroup; import android.view.animation.AnimationUtils; import android.view.animation.LinearInterpolator; import android.view.animation.RotateAnimation; import android.widget.AbsListView; import android.widget.RelativeLayout; import android.widget.TextView; /** * 整個(gè)下拉刷新就這一個(gè)布局，用來管理兩個(gè)子控件，其中一個(gè)是下拉頭，另一個(gè)是包含內(nèi)容的contentView（可以是AbsListView的任何子類） * * @author 陳靖 */ public class PullToRefreshLayout extends RelativeLayout implements OnTouchListener { public static final String TAG = "PullToRefreshLayout"; // 下拉刷新 public static final int PULL_TO_REFRESH = 0; // 釋放刷新 public static final int RELEASE_TO_REFRESH = 1; // 正在刷新 public static final int REFRESHING = 2; // 刷新完畢 public static final int DONE = 3; // 當(dāng)前狀態(tài) private int state = PULL_TO_REFRESH; // 刷新回調(diào)接口 private OnRefreshListener mListener; // 刷新成功 public static final int REFRESH_SUCCEED = 0; // 刷新失敗 public static final int REFRESH_FAIL = 1; // 下拉頭 private View headView; // 內(nèi)容 private View contentView; // 按下Y坐標(biāo)，上一個(gè)事件點(diǎn)Y坐標(biāo) private float downY, lastY; // 下拉的距離 public float moveDeltaY = 0; // 釋放刷新的距離 private float refreshDist = 200; private Timer timer; private MyTimerTask mTask; // 回滾速度 public float MOVE_SPEED = 8; // 第一次執(zhí)行布局 private boolean isLayout = false; // 是否可以下拉 private boolean canPull = true; // 在刷新過程中滑動(dòng)操作 private boolean isTouchInRefreshing = false; // 手指滑動(dòng)距離與下拉頭的滑動(dòng)距離比，中間會(huì)隨正切函數(shù)變化 private float radio = 2; // 下拉箭頭的轉(zhuǎn)180°動(dòng)畫 private RotateAnimation rotateAnimation; // 均勻旋轉(zhuǎn)動(dòng)畫 private RotateAnimation refreshingAnimation; // 下拉的箭頭 private View pullView; // 正在刷新的圖標(biāo) private View refreshingView; // 刷新結(jié)果圖標(biāo) private View stateImageView; // 刷新結(jié)果：成功或失敗 private TextView stateTextView; /** * 執(zhí)行自動(dòng)回滾的handler */ Handler updateHandler = new Handler() { @Override public void handleMessage(Message msg) { // 回彈速度隨下拉距離moveDeltaY增大而增大 MOVE_SPEED = (float) (8 + 5 * Math.tan(Math.PI / 2 / getMeasuredHeight() * moveDeltaY)); if (state == REFRESHING && moveDeltaY <= refreshDist && !isTouchInRefreshing) { // 正在刷新，且沒有往上推的話則懸停，顯示"正在刷新..." moveDeltaY = refreshDist; mTask.cancel(); } if (canPull) moveDeltaY -= MOVE_SPEED; if (moveDeltaY <= 0) { // 已完成回彈 moveDeltaY = 0; pullView.clearAnimation(); // 隱藏下拉頭時(shí)有可能還在刷新，只有當(dāng)前狀態(tài)不是正在刷新時(shí)才改變狀態(tài) if (state != REFRESHING) changeState(PULL_TO_REFRESH); mTask.cancel(); } // 刷新布局,會(huì)自動(dòng)調(diào)用onLayout requestLayout(); } }; public void setOnRefreshListener(OnRefreshListener listener) { mListener = listener; } public PullToRefreshLayout(Context context) { super(context); initView(context); } public PullToRefreshLayout(Context context, AttributeSet attrs) { super(context, attrs); initView(context); } public PullToRefreshLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(context); } private void initView(Context context) { timer = new Timer(); mTask = new MyTimerTask(updateHandler); rotateAnimation = (RotateAnimation) AnimationUtils.loadAnimation(context, R.anim.reverse_anim); refreshingAnimation = (RotateAnimation) AnimationUtils.loadAnimation(context, R.anim.rotating); // 添加勻速轉(zhuǎn)動(dòng)動(dòng)畫 LinearInterpolator lir = new LinearInterpolator(); rotateAnimation.setInterpolator(lir); refreshingAnimation.setInterpolator(lir); } private void hideHead() { if (mTask != null) { mTask.cancel(); mTask = null; } mTask = new MyTimerTask(updateHandler); timer.schedule(mTask, 0, 5); } /** * 完成刷新操作，顯示刷新結(jié)果 */ public void refreshFinish(int refreshResult) { refreshingView.clearAnimation(); refreshingView.setVisibility(View.GONE); switch (refreshResult) { case REFRESH_SUCCEED: // 刷新成功 stateImageView.setVisibility(View.VISIBLE); stateTextView.setText(R.string.refresh_succeed); stateImageView.setBackgroundResource(R.drawable.refresh_succeed); break; case REFRESH_FAIL: // 刷新失敗 stateImageView.setVisibility(View.VISIBLE); stateTextView.setText(R.string.refresh_fail); stateImageView.setBackgroundResource(R.drawable.refresh_failed); break; default: break; } // 刷新結(jié)果停留1秒 new Handler() { @Override public void handleMessage(Message msg) { state = PULL_TO_REFRESH; hideHead(); } }.sendEmptyMessageDelayed(0, 1000); } private void changeState(int to) { state = to; switch (state) { case PULL_TO_REFRESH: // 下拉刷新 stateImageView.setVisibility(View.GONE); stateTextView.setText(R.string.pull_to_refresh); pullView.clearAnimation(); pullView.setVisibility(View.VISIBLE); break; case RELEASE_TO_REFRESH: // 釋放刷新 stateTextView.setText(R.string.release_to_refresh); pullView.startAnimation(rotateAnimation); break; case REFRESHING: // 正在刷新 pullView.clearAnimation(); refreshingView.setVisibility(View.VISIBLE); pullView.setVisibility(View.INVISIBLE); refreshingView.startAnimation(refreshingAnimation); stateTextView.setText(R.string.refreshing); break; default: break; } } /* * （非 Javadoc）由父控件決定是否分發(fā)事件，防止事件沖突 * * @see android.view.ViewGroup#dispatchTouchEvent(android.view.MotionEvent) */ @Override public boolean dispatchTouchEvent(MotionEvent ev) { switch (ev.getActionMasked()) { case MotionEvent.ACTION_DOWN: downY = ev.getY(); lastY = downY; if (mTask != null) { mTask.cancel(); } /* * 觸碰的地方位于下拉頭布局，由于我們沒有對(duì)下拉頭做事件響應(yīng)，這時(shí)候它會(huì)給咱返回一個(gè)false導(dǎo)致接下來的事件不再分發(fā)進(jìn)來。 * 所以我們不能交給父類分發(fā)，直接返回true */ if (ev.getY() < moveDeltaY) return true; break; case MotionEvent.ACTION_MOVE: // canPull這個(gè)值在底下onTouch中會(huì)根據(jù)ListView是否滑到頂部來改變，意思是是否可下拉 if (canPull) { // 對(duì)實(shí)際滑動(dòng)距離做縮小，造成用力拉的感覺 moveDeltaY = moveDeltaY + (ev.getY() - lastY) / radio; if (moveDeltaY < 0) moveDeltaY = 0; if (moveDeltaY > getMeasuredHeight()) moveDeltaY = getMeasuredHeight(); if (state == REFRESHING) { // 正在刷新的時(shí)候觸摸移動(dòng) isTouchInRefreshing = true; } } lastY = ev.getY(); // 根據(jù)下拉距離改變比例 radio = (float) (2 + 2 * Math.tan(Math.PI / 2 / getMeasuredHeight() * moveDeltaY)); requestLayout(); if (moveDeltaY <= refreshDist && state == RELEASE_TO_REFRESH) { // 如果下拉距離沒達(dá)到刷新的距離且當(dāng)前狀態(tài)是釋放刷新，改變狀態(tài)為下拉刷新 changeState(PULL_TO_REFRESH); } if (moveDeltaY >= refreshDist && state == PULL_TO_REFRESH) { changeState(RELEASE_TO_REFRESH); } if (moveDeltaY > 8) { // 防止下拉過程中誤觸發(fā)長(zhǎng)按事件和點(diǎn)擊事件 clearContentViewEvents(); } if (moveDeltaY > 0) { // 正在下拉，不讓子控件捕獲事件 return true; } break; case MotionEvent.ACTION_UP: if (moveDeltaY > refreshDist) // 正在刷新時(shí)往下拉釋放后下拉頭不隱藏 isTouchInRefreshing = false; if (state == RELEASE_TO_REFRESH) { changeState(REFRESHING); // 刷新操作 if (mListener != null) mListener.onRefresh(); } else { } hideHead(); default: break; } // 事件分發(fā)交給父類 return super.dispatchTouchEvent(ev); } /** * 通過反射修改字段去掉長(zhǎng)按事件和點(diǎn)擊事件 */ private void clearContentViewEvents() { try { Field[] fields = AbsListView.class.getDeclaredFields(); for (int i = 0; i < fields.length; i++) if (fields[i].getName().equals("mPendingCheckForLongPress")) { // mPendingCheckForLongPress是AbsListView中的字段，通過反射獲取并從消息列表刪除，去掉長(zhǎng)按事件 fields[i].setAccessible(true); contentView.getHandler().removeCallbacks((Runnable) fields[i].get(contentView)); } else if (fields[i].getName().equals("mTouchMode")) { // TOUCH_MODE_REST = -1， 這個(gè)可以去除點(diǎn)擊事件 fields[i].setAccessible(true); fields[i].set(contentView, -1); } // 去掉焦點(diǎn) ((AbsListView) contentView).getSelector().setState(new int[] { 0 }); } catch (Exception e) { Log.d(TAG, "error : " + e.toString()); } } /* * （非 Javadoc）繪制陰影效果，顏色值可以修改 * * @see android.view.ViewGroup#dispatchDraw(android.graphics.Canvas) */ @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); if (moveDeltaY == 0) return; RectF rectF = new RectF(0, 0, getMeasuredWidth(), moveDeltaY); Paint paint = new Paint(); paint.setAntiAlias(true); // 陰影的高度為26 LinearGradient linearGradient = new LinearGradient(0, moveDeltaY, 0, moveDeltaY - 26, 0x66000000, 0x00000000, TileMode.CLAMP); paint.setShader(linearGradient); paint.setStyle(Style.FILL); // 在moveDeltaY處往上變淡 canvas.drawRect(rectF, paint); } private void initView() { pullView = headView.findViewById(R.id.pull_icon); stateTextView = (TextView) headView.findViewById(R.id.state_tv); refreshingView = headView.findViewById(R.id.refreshing_icon); stateImageView = headView.findViewById(R.id.state_iv); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { if (!isLayout) { // 這里是第一次進(jìn)來的時(shí)候做一些初始化 headView = getChildAt(0); contentView = getChildAt(1); // 給AbsListView設(shè)置OnTouchListener contentView.setOnTouchListener(this); isLayout = true; initView(); refreshDist = ((ViewGroup) headView).getChildAt(0).getMeasuredHeight(); } if (canPull) { // 改變子控件的布局 headView.layout(0, (int) moveDeltaY - headView.getMeasuredHeight(), headView.getMeasuredWidth(), (int) moveDeltaY); contentView.layout(0, (int) moveDeltaY, contentView.getMeasuredWidth(), (int) moveDeltaY + contentView.getMeasuredHeight()); }else super.onLayout(changed, l, t, r, b); } class MyTimerTask extends TimerTask { Handler handler; public MyTimerTask(Handler handler) { this.handler = handler; } @Override public void run() { handler.sendMessage(handler.obtainMessage()); } } @Override public boolean onTouch(View v, MotionEvent event) { // 第一個(gè)item可見且滑動(dòng)到頂部 AbsListView alv = null; try { alv = (AbsListView) v; } catch (Exception e) { Log.d(TAG, e.getMessage()); return false; } if (alv.getCount() == 0) { // 沒有item的時(shí)候也可以下拉刷新 canPull = true; } else if (alv.getFirstVisiblePosition() == 0 && alv.getChildAt(0).getTop() >= 0) { // 滑到AbsListView的頂部了 canPull = true; } else canPull = false; return false; } } 代碼中的注釋已經(jīng)寫的很清楚了。
既然PullToRefreshLayout已經(jīng)寫好了，接下來就來使用這個(gè)Layout實(shí)現(xiàn)下拉刷新~
首先得寫個(gè)OnRefreshListener接口來回調(diào)刷新操作：
public interface OnRefreshListener { void onRefresh(); } 就一個(gè)刷新操作的方法，待會(huì)兒讓Activity實(shí)現(xiàn)這個(gè)接口就可以在Activity中執(zhí)行刷新操作了。
看一下MainActivity的布局：
<com.jingchen.pulltorefresh.PullToRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/refresh_view" android:layout_width="match_parent" android:layout_height="match_parent" > <include layout="@layout/refresh_head" /> <!-- 支持AbsListView的所有子類 --> <ListView android:id="@+id/content_view" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/white" android:divider="@color/gray" android:dividerHeight="1dp" > </ListView> </com.jingchen.pulltorefresh.PullToRefreshLayout>
PullToRefreshLayout只能包含兩個(gè)子控件：refresh_head和content_view。
看一下refresh_head的布局：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/head_view" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/light_blue" > <RelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:paddingBottom="20dp" android:paddingTop="20dp" > <RelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_centerInParent="true" > <ImageView android:id="@+id/pull_icon" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="60dp" android:background="@drawable/pull_icon_big" /> <ImageView android:id="@+id/refreshing_icon" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="60dp" android:background="@drawable/refreshing" android:visibility="gone" /> <TextView android:id="@+id/state_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="@string/pull_to_refresh" android:textColor="@color/white" android:textSize="16sp" /> <ImageView android:id="@+id/state_iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginRight="8dp" android:layout_toLeftOf="@id/state_tv" android:visibility="gone" /> </RelativeLayout> </RelativeLayout> </RelativeLayout>
可以根據(jù)需要修改refresh_head的布局然后在PullToRefreshLayout中處理，但是相關(guān)View的id要和PullToRefreshLayout中用到的保持同步！
接下來是MainActivity的代碼：
package com.jingchen.pulltorefresh; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.view.animation.AnimationUtils; import android.view.animation.LinearInterpolator; import android.view.animation.RotateAnimation; import android.widget.AbsListView; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.AdapterView.OnItemLongClickListener; import android.widget.BaseExpandableListAdapter; import android.widget.ExpandableListView; import android.widget.ExpandableListView.OnChildClickListener; import android.widget.ExpandableListView.OnGroupClickListener; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; /** * 除了下拉刷新，在contenview為L(zhǎng)istView的情況下我給ListView增加了FooterView，實(shí)現(xiàn)點(diǎn)擊加載更多 * * @author 陳靖 * */ public class MainActivity extends Activity implements OnRefreshListener, OnClickListener { private AbsListView alv; private PullToRefreshLayout refreshLayout; private View loading; private RotateAnimation loadingAnimation; private TextView loadTextView; private MyAdapter adapter; private boolean isLoading = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } private void init() { alv = (AbsListView) findViewById(R.id.content_view); refreshLayout = (PullToRefreshLayout) findViewById(R.id.refresh_view); refreshLayout.setOnRefreshListener(this); initListView(); loadingAnimation = (RotateAnimation) AnimationUtils.loadAnimation(this, R.anim.rotating); // 添加勻速轉(zhuǎn)動(dòng)動(dòng)畫 LinearInterpolator lir = new LinearInterpolator(); loadingAnimation.setInterpolator(lir); } /** * ListView初始化方法 */ private void initListView() { List<String> items = new ArrayList<String>(); for (int i = 0; i < 30; i++) { items.add("這里是item " + i); } // 添加head View headView = getLayoutInflater().inflate(R.layout.listview_head, null); ((ListView) alv).addHeaderView(headView, null, false); // 添加footer View footerView = getLayoutInflater().inflate(R.layout.load_more, null); loading = footerView.findViewById(R.id.loading_icon); loadTextView = (TextView) footerView.findViewById(R.id.loadmore_tv); ((ListView) alv).addFooterView(footerView, null, false); footerView.setOnClickListener(this); adapter = new MyAdapter(this, items); alv.setAdapter(adapter); alv.setOnItemLongClickListener(new OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(MainActivity.this, "LongClick on " + parent.getAdapter().getItemId(position), Toast.LENGTH_SHORT).show(); return true; } }); alv.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(MainActivity.this, " Click on " + parent.getAdapter().getItemId(position), Toast.LENGTH_SHORT).show(); } }); } /** * GridView初始化方法 */ private void initGridView() { List<String> items = new ArrayList<String>(); for (int i = 0; i < 30; i++) { items.add("這里是item " + i); } adapter = new MyAdapter(this, items); alv.setAdapter(adapter); alv.setOnItemLongClickListener(new OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(MainActivity.this, "LongClick on " + parent.getAdapter().getItemId(position), Toast.LENGTH_SHORT).show(); return true; } }); alv.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(MainActivity.this, " Click on " + parent.getAdapter().getItemId(position), Toast.LENGTH_SHORT).show(); } }); } /** * ExpandableListView初始化方法 */ private void initExpandableListView() { ((ExpandableListView) alv).setAdapter(new ExpandableListAdapter(this)); ((ExpandableListView) alv).setOnChildClickListener(new OnChildClickListener() { @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { Toast.makeText(MainActivity.this, " Click on group " + groupPosition + " item " + childPosition, Toast.LENGTH_SHORT).show(); return true; } }); ((ExpandableListView) alv).setOnItemLongClickListener(new OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(MainActivity.this, "LongClick on " + parent.getAdapter().getItemId(position), Toast.LENGTH_SHORT).show(); return true; } }); ((ExpandableListView) alv).setOnGroupClickListener(new OnGroupClickListener() { @Override public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) { if (parent.isGroupExpanded(groupPosition)) { // 如果展開則關(guān)閉 parent.collapseGroup(groupPosition); } else { // 如果關(guān)閉則打開，注意這里是手動(dòng)打開不要默認(rèn)滾動(dòng)否則會(huì)有bug parent.expandGroup(groupPosition); } return true; } }); } @Override public void onRefresh() { // 下拉刷新操作 new Handler() { @Override public void handleMessage(Message msg) { refreshLayout.refreshFinish(PullToRefreshLayout.REFRESH_SUCCEED); } }.sendEmptyMessageDelayed(0, 5000); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.loadmore_layout: if (!isLoading) { loading.setVisibility(View.VISIBLE); loading.startAnimation(loadingAnimation); loadTextView.setText(R.string.loading); isLoading = true; } break; default: break; } } class ExpandableListAdapter extends BaseExpandableListAdapter { private String[] groupsStrings;// = new String[] { "這里是group 0", // "這里是group 1", "這里是group 2" }; private String[][] groupItems; private Context context; public ExpandableListAdapter(Context context) { this.context = context; groupsStrings = new String[8]; for (int i = 0; i < groupsStrings.length; i++) { groupsStrings[i] = new String("這里是group " + i); } groupItems = new String[8][8]; for (int i = 0; i < groupItems.length; i++) for (int j = 0; j < groupItems[i].length; j++) { groupItems[i][j] = new String("這里是group " + i + "里的item " + j); } } @Override public int getGroupCount() { return groupsStrings.length; } @Override public int getChildrenCount(int groupPosition) { return groupItems[groupPosition].length; } @Override public Object getGroup(int groupPosition) { return groupsStrings[groupPosition]; } @Override public Object getChild(int groupPosition, int childPosition) { return groupItems[groupPosition][childPosition]; } @Override public long getGroupId(int groupPosition) { return groupPosition; } @Override public long getChildId(int groupPosition, int childPosition) { return childPosition; } @Override public boolean hasStableIds() { return true; } @Override public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { View view = LayoutInflater.from(context).inflate(R.layout.list_item_layout, null); TextView tv = (TextView) view.findViewById(R.id.name_tv); tv.setText(groupsStrings[groupPosition]); return view; } @Override public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { View view = LayoutInflater.from(context).inflate(R.layout.list_item_layout, null); TextView tv = (TextView) view.findViewById(R.id.name_tv); tv.setText(groupItems[groupPosition][childPosition]); return view; } @Override public boolean isChildSelectable(int groupPosition, int childPosition) { return true; } } } 在MainActivity中判斷contentView是ListView的話給ListView添加了FooterView實(shí)現(xiàn)點(diǎn)擊加載更多的功能。這只是一個(gè)演示PullToRefreshLayout使用的demo，可以參照一下修改。我已經(jīng)在里面寫了ListView，GridView和ExpandableListView的初始化方法，根據(jù)自己使用的是哪個(gè)來調(diào)用吧。那么這是ListView的下拉刷新和加載更多。如果我要GridView也有下拉刷新功能呢？那就把MainActivity的布局換成這樣：
<com.jingchen.pulltorefresh.PullToRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/refresh_view" android:layout_width="match_parent" android:layout_height="match_parent" > <include layout="@layout/refresh_head" /> <!-- 支持AbsListView的所有子類 --> <GridView android:id="@+id/content_view" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/white" android:columnWidth="90dp" android:gravity="center" android:horizontalSpacing="10dp" android:numColumns="auto_fit" android:stretchMode="columnWidth" android:verticalSpacing="15dp" > </GridView> </com.jingchen.pulltorefresh.PullToRefreshLayout>
如果是ExpandableListView則把布局改成這樣：
<com.jingchen.pulltorefresh.PullToRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/refresh_view" android:layout_width="match_parent" android:layout_height="match_parent" > <include layout="@layout/refresh_head" /> <!-- 支持AbsListView的所有子類 --> <ExpandableListView android:id="@+id/content_view" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/white" > </ExpandableListView> </com.jingchen.pulltorefresh.PullToRefreshLayout>
怎么樣？很簡(jiǎn)單吧？簡(jiǎn)單易用，不用再去繼承修改了。
本文已經(jīng)被整理到《Android下拉刷新上拉加載效果》，歡迎大家學(xué)習(xí)研究。
希望本文所述對(duì)大家學(xué)習(xí)Android下拉刷新控件有所幫助。
新聞熱點(diǎn)
疑難解答
圖片精選
