转载请声明出处
前面写过一篇关于下拉刷新控件的博客,后来看到好多人还有上拉加载更多的需求,于是就在前面下拉刷新控件的基础上进行了改进,加了上拉加载的功能。不仅如此,我已经把它改成了对所有View都通用!可以随心所欲使用这两个功能~~
我做了一个大集合的demo,实现了ListView、GridView、ExpandableListView、ScrollView、WebView、ImageView、TextView的下拉刷新和上拉加载。后面会提供demo的下载地址。(csdn上的demo有小bug,最新代码已上传到github:)
依照惯例,下面将会是一大波效果图:
demo首页也是可下拉的ListView,在底下可以加入table:
ListView:
GridView:
ExpandableListView:
ScrollView:
WebView:
ImageView:
TextView:
很不错吧?最后的ImageView和TextView是最简单的,直接在下面的接口方法里返回true。
增加上拉加载很简单,和管理下拉头一样,再多管理一个上拉头,也不费事;至于把它改成通用的就需要统一一下View的行为了,为此,我定义了这样一个接口:
- package com.jingchen.pulltorefresh.pullableview;
-
- public interface Pullable
- {
-
-
-
-
-
- boolean canPullDown();
-
-
-
-
-
-
- boolean canPullUp();
- }
从接口名就可以看出它是一个提供判断是否可拉的方法的接口。这个接口的两个方法,canPullDown()是判断何时可以下拉的方法,canPullUp()则是判断何时可以上拉,我在demo中的判断是滑到顶部的时候可以下拉,滑到底部的时候可以上拉。所有需要上拉和下拉的View都需要实现这个接口。后面会给出一些View的实现。先来看看改进后的自定义的布局PullToRefreshLayout,增加了一个上拉头,下拉头和上拉头之间的View是实现了Pullable接口的pullableView。相比前面的版本,这里有改动的需要注意的地方如下: 1、增加了上拉头,相应的也增加了控制变量。
2、拉动时消除content_view事件防止误触发不再使用反射,直接设置 event.setAction(MotionEvent.ACTION_CANCEL)。
3、消除了拉动过程中的多点触碰导致的剧变。
4、不再设置content_view的onTouListener,让使用者可以更加自由的设置监听器。
这个PullToRefreshLayout只负责管理三个控件,如果一个View需要有上拉下拉功能则只需实现接口就行了。下面看PullToRefreshLayout的代码,注释写了好多:
- package com.jingchen.pulltorefresh;
-
- 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.ViewGroup;
- import android.view.animation.AnimationUtils;
- import android.view.animation.LinearInterpolator;
- import android.view.animation.RotateAnimation;
- import android.widget.RelativeLayout;
- import android.widget.TextView;
-
- import com.jingchen.pulltorefresh.pullableview.Pullable;
-
-
-
-
-
-
-
- public class PullToRefreshLayout extends RelativeLayout
- {
- public static final String TAG = "PullToRefreshLayout";
-
- public static final int INIT = 0;
-
- public static final int RELEASE_TO_REFRESH = 1;
-
- public static final int REFRESHING = 2;
-
- public static final int RELEASE_TO_LOAD = 3;
-
- public static final int LOADING = 4;
-
- public static final int DONE = 5;
-
- private int state = INIT;
-
- private OnRefreshListener mListener;
-
- public static final int SUCCEED = 0;
-
- public static final int FAIL = 1;
-
- private float downY, lastY;
-
-
- public float pullDownY = 0;
-
- private float pullUpY = 0;
-
-
- private float refreshDist = 200;
-
- private float loadmoreDist = 200;
-
- private MyTimer timer;
-
- public float MOVE_SPEED = 8;
-
- private boolean isLayout = false;
-
- private boolean isTouch = false;
-
- private float radio = 2;
-
-
- private RotateAnimation rotateAnimation;
-
- private RotateAnimation refreshingAnimation;
-
-
- private View refreshView;
-
- private View pullView;
-
- private View refreshingView;
-
- private View refreshStateImageView;
-
- private TextView refreshStateTextView;
-
-
- private View loadmoreView;
-
- private View pullUpView;
-
- private View loadingView;
-
- private View loadStateImageView;
-
- private TextView loadStateTextView;
-
-
- private View pullableView;
-
- private int mEvents;
-
- private boolean canPullDown = true;
- private boolean canPullUp = true;
-
-
-
-
- Handler updateHandler = new Handler()
- {
-
- @Override
- public void handleMessage(Message msg)
- {
-
- MOVE_SPEED = (float) (8 + 5 * Math.tan(Math.PI / 2
- / getMeasuredHeight() * (pullDownY + Math.abs(pullUpY))));
- if (!isTouch)
- {
-
- if (state == REFRESHING && pullDownY <= refreshDist)
- {
- pullDownY = refreshDist;
- timer.cancel();
- } else if (state == LOADING && -pullUpY <= loadmoreDist)
- {
- pullUpY = -loadmoreDist;
- timer.cancel();
- }
-
- }
- if (pullDownY > 0)
- pullDownY -= MOVE_SPEED;
- else if (pullUpY < 0)
- pullUpY += MOVE_SPEED;
- if (pullDownY < 0)
- {
-
- pullDownY = 0;
- pullView.clearAnimation();
-
- if (state != REFRESHING && state != LOADING)
- changeState(INIT);
- timer.cancel();
- }
- if (pullUpY > 0)
- {
-
- pullUpY = 0;
- pullUpView.clearAnimation();
-
- if (state != REFRESHING && state != LOADING)
- changeState(INIT);
- timer.cancel();
- }
-
- 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 MyTimer(updateHandler);
- rotateAnimation = (RotateAnimation) AnimationUtils.loadAnimation(
- context, R.anim.reverse_anim);
- refreshingAnimation = (RotateAnimation) AnimationUtils.loadAnimation(
- context, R.anim.rotating);
-
- LinearInterpolator lir = new LinearInterpolator();
- rotateAnimation.setInterpolator(lir);
- refreshingAnimation.setInterpolator(lir);
- }
-
- private void hide()
- {
- timer.schedule(5);
- }
-
-
-
-
-
-
-
-
- public void refreshFinish(int refreshResult)
- {
- refreshingView.clearAnimation();
- refreshingView.setVisibility(View.GONE);
- switch (refreshResult)
- {
- case SUCCEED:
-
- refreshStateImageView.setVisibility(View.VISIBLE);
- refreshStateTextView.setText(R.string.refresh_succeed);
- refreshStateImageView
- .setBackgroundResource(R.drawable.refresh_succeed);
- break;
- case FAIL:
- default:
-
- refreshStateImageView.setVisibility(View.VISIBLE);
- refreshStateTextView.setText(R.string.refresh_fail);
- refreshStateImageView
- .setBackgroundResource(R.drawable.refresh_failed);
- break;
- }
-
- new Handler()
- {
- @Override
- public void handleMessage(Message msg)
- {
- changeState(DONE);
- hide();
- }
- }.sendEmptyMessageDelayed(0, 1000);
- }
-
-
-
-
-
-
-
- public void loadmoreFinish(int refreshResult)
- {
- loadingView.clearAnimation();
- loadingView.setVisibility(View.GONE);
- switch (refreshResult)
- {
- case SUCCEED:
-
- loadStateImageView.setVisibility(View.VISIBLE);
- loadStateTextView.setText(R.string.load_succeed);
- loadStateImageView.setBackgroundResource(R.drawable.load_succeed);
- break;
- case FAIL:
- default:
-
- loadStateImageView.setVisibility(View.VISIBLE);
- loadStateTextView.setText(R.string.load_fail);
- loadStateImageView.setBackgroundResource(R.drawable.load_failed);
- break;
- }
-
- new Handler()
- {
- @Override
- public void handleMessage(Message msg)
- {
- changeState(DONE);
- hide();
- }
- }.sendEmptyMessageDelayed(0, 1000);
- }
-
- private void changeState(int to)
- {
- state = to;
- switch (state)
- {
- case INIT:
-
- refreshStateImageView.setVisibility(View.GONE);
- refreshStateTextView.setText(R.string.pull_to_refresh);
- pullView.clearAnimation();
- pullView.setVisibility(View.VISIBLE);
-
- loadStateImageView.setVisibility(View.GONE);
- loadStateTextView.setText(R.string.pullup_to_load);
- pullUpView.clearAnimation();
- pullUpView.setVisibility(View.VISIBLE);
- break;
- case RELEASE_TO_REFRESH:
-
- refreshStateTextView.setText(R.string.release_to_refresh);
- pullView.startAnimation(rotateAnimation);
- break;
- case REFRESHING:
-
- pullView.clearAnimation();
- refreshingView.setVisibility(View.VISIBLE);
- pullView.setVisibility(View.INVISIBLE);
- refreshingView.startAnimation(refreshingAnimation);
- refreshStateTextView.setText(R.string.refreshing);
- break;
- case RELEASE_TO_LOAD:
-
- loadStateTextView.setText(R.string.release_to_load);
- pullUpView.startAnimation(rotateAnimation);
- break;
- case LOADING:
-
- pullUpView.clearAnimation();
- loadingView.setVisibility(View.VISIBLE);
- pullUpView.setVisibility(View.INVISIBLE);
- loadingView.startAnimation(refreshingAnimation);
- loadStateTextView.setText(R.string.loading);
- break;
- case DONE:
-
- break;
- }
- }
-
-
-
-
- private void releasePull()
- {
- canPullDown = true;
- canPullUp = true;
- }
-
-
-
-
-
-
- @Override
- public boolean dispatchTouchEvent(MotionEvent ev)
- {
- switch (ev.getActionMasked())
- {
- case MotionEvent.ACTION_DOWN:
- downY = ev.getY();
- lastY = downY;
- timer.cancel();
- mEvents = 0;
- releasePull();
- break;
- case MotionEvent.ACTION_POINTER_DOWN:
- case MotionEvent.ACTION_POINTER_UP:
-
- mEvents = -1;
- break;
- case MotionEvent.ACTION_MOVE:
- if (mEvents == 0)
- {
- if (((Pullable) pullableView).canPullDown() && canPullDown
- && state != LOADING)
- {
-
-
- pullDownY = pullDownY + (ev.getY() - lastY) / radio;
- if (pullDownY < 0)
- {
- pullDownY = 0;
- canPullDown = false;
- canPullUp = true;
- }
- if (pullDownY > getMeasuredHeight())
- pullDownY = getMeasuredHeight();
- if (state == REFRESHING)
- {
-
- isTouch = true;
- }
- } else if (((Pullable) pullableView).canPullUp() && canPullUp
- && state != REFRESHING)
- {
-
- pullUpY = pullUpY + (ev.getY() - lastY) / radio;
- if (pullUpY > 0)
- {
- pullUpY = 0;
- canPullDown = true;
- canPullUp = false;
- }
- if (pullUpY < -getMeasuredHeight())
- pullUpY = -getMeasuredHeight();
- if (state == LOADING)
- {
-
- isTouch = true;
- }
- } else
- releasePull();
- } else
- mEvents = 0;
- lastY = ev.getY();
-
- radio = (float) (2 + 2 * Math.tan(Math.PI / 2 / getMeasuredHeight()
- * (pullDownY + Math.abs(pullUpY))));
- requestLayout();
- if (pullDownY <= refreshDist
- <span style="white-space:pre"> </span>&& (state == RELEASE_TO_REFRESH || state == DONE)) {
- <span style="white-space:pre"> </span>
- <span style="white-space:pre"> </span>changeState(INIT);
- <span style="white-space:pre"> </span>}
- <span style="white-space:pre"> </span>if (pullDownY >= refreshDist && (state == INIT || state == DONE)) {
- <span style="white-space:pre"> </span>
- <span style="white-space:pre"> </span>changeState(RELEASE_TO_REFRESH);
- <span style="white-space:pre"> </span>}
- <span style="white-space:pre"> </span>
- <span style="white-space:pre"> </span>if (-pullUpY <= loadmoreDist
- <span style="white-space:pre"> </span>&& (state == RELEASE_TO_LOAD || state == DONE)) {
- <span style="white-space:pre"> </span>changeState(INIT);
- <span style="white-space:pre"> </span>}
- <span style="white-space:pre"> </span>if (-pullUpY >= loadmoreDist && (state == INIT || state == DONE)) {
- <span style="white-space:pre"> </span>changeState(RELEASE_TO_LOAD);
- <span style="white-space:pre"> </span>}
-
-
- if ((pullDownY + Math.abs(pullUpY)) > 8)
- {
-
- ev.setAction(MotionEvent.ACTION_CANCEL);
- }
- break;
- case MotionEvent.ACTION_UP:
- if (pullDownY > refreshDist || -pullUpY > loadmoreDist)
-
- isTouch = false;
- if (state == RELEASE_TO_REFRESH)
- {
- changeState(REFRESHING);
-
- if (mListener != null)
- mListener.onRefresh(this);
- } else if (state == RELEASE_TO_LOAD)
- {
- changeState(LOADING);
-
- if (mListener != null)
- mListener.onLoadMore(this);
- }
- hide();
- default:
- break;
- }
-
- super.dispatchTouchEvent(ev);
- return true;
- }
-
- private void initView()
- {
-
- pullView = refreshView.findViewById(R.id.pull_icon);
- refreshStateTextView = (TextView) refreshView
- .findViewById(R.id.state_tv);
- refreshingView = refreshView.findViewById(R.id.refreshing_icon);
- refreshStateImageView = refreshView.findViewById(R.id.state_iv);
-
- pullUpView = loadmoreView.findViewById(R.id.pullup_icon);
- loadStateTextView = (TextView) loadmoreView
- .findViewById(R.id.loadstate_tv);
- loadingView = loadmoreView.findViewById(R.id.loading_icon);
- loadStateImageView = loadmoreView.findViewById(R.id.loadstate_iv);
- }
-
- @Override
- protected void onLayout(boolean changed, int l, int t, int r, int b)
- {
- if (!isLayout)
- {
-
- refreshView = getChildAt(0);
- pullableView = getChildAt(1);
- loadmoreView = getChildAt(2);
- isLayout = true;
- initView();
- refreshDist = ((ViewGroup) refreshView).getChildAt(0)
- .getMeasuredHeight();
- loadmoreDist = ((ViewGroup) loadmoreView).getChildAt(0)
- .getMeasuredHeight();
- }
-
- refreshView.layout(0,
- (int) (pullDownY + pullUpY) - refreshView.getMeasuredHeight(),
- refreshView.getMeasuredWidth(), (int) (pullDownY + pullUpY));
- pullableView.layout(0, (int) (pullDownY + pullUpY),
- pullableView.getMeasuredWidth(), (int) (pullDownY + pullUpY)
- + pullableView.getMeasuredHeight());
- loadmoreView.layout(0,
- (int) (pullDownY + pullUpY) + pullableView.getMeasuredHeight(),
- loadmoreView.getMeasuredWidth(),
- (int) (pullDownY + pullUpY) + pullableView.getMeasuredHeight()
- + loadmoreView.getMeasuredHeight());
- }
-
- class MyTimer
- {
- private Handler handler;
- private Timer timer;
- private MyTask mTask;
-
- public MyTimer(Handler handler)
- {
- this.handler = handler;
- timer = new Timer();
- }
-
- public void schedule(long period)
- {
- if (mTask != null)
- {
- mTask.cancel();
- mTask = null;
- }
- mTask = new MyTask(handler);
- timer.schedule(mTask, 0, period);
- }
-
- public void cancel()
- {
- if (mTask != null)
- {
- mTask.cancel();
- mTask = null;
- }
- }
-
- class MyTask extends TimerTask
- {
- private Handler handler;
-
- public MyTask(Handler handler)
- {
- this.handler = handler;
- }
-
- @Override
- public void run()
- {
- handler.obtainMessage().sendToTarget();
- }
-
- }
- }
-
-
-
-
-
-
-
- public interface OnRefreshListener
- {
-
-
-
- void onRefresh(PullToRefreshLayout pullToRefreshLayout);
-
-
-
-
- void onLoadMore(PullToRefreshLayout pullToRefreshLayout);
- }
-
- }
上面就是整个布局的代码,并不是很难。 下面看各个View对Pullable接口的实现,ListView和GridView还有ExpandableListView的判断方法是一样的:
PullableListView:
- package com.jingchen.pulltorefresh.pullableview;
-
- import android.content.Context;
- import android.util.AttributeSet;
- import android.util.Log;
- import android.widget.ListView;
-
- public class PullableListView extends ListView implements Pullable
- {
-
- public PullableListView(Context context)
- {
- super(context);
- }
-
- public PullableListView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public PullableListView(Context context, AttributeSet attrs, int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- public boolean canPullDown()
- {
- if (getCount() == 0)
- {
-
- return true;
- } else if (getFirstVisiblePosition() == 0
- && getChildAt(0).getTop() >= 0)
- {
-
- return true;
- } else
- return false;
- }
-
- @Override
- public boolean canPullUp()
- {
- if (getCount() == 0)
- {
-
- return true;
- } else if (getLastVisiblePosition() == (getCount() - 1))
- {
-
- if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null
- && getChildAt(
- getLastVisiblePosition()
- - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight())
- return true;
- }
- return false;
- }
- }
PullableExpandableListView:
- package com.jingchen.pulltorefresh.pullableview;
-
- import android.content.Context;
- import android.util.AttributeSet;
- import android.widget.ExpandableListView;
-
- public class PullableExpandableListView extends ExpandableListView implements
- Pullable
- {
-
- public PullableExpandableListView(Context context)
- {
- super(context);
- }
-
- public PullableExpandableListView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public PullableExpandableListView(Context context, AttributeSet attrs,
- int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- public boolean canPullDown()
- {
- if (getCount() == 0)
- {
-
- return true;
- } else if (getFirstVisiblePosition() == 0
- && getChildAt(0).getTop() >= 0)
- {
-
- return true;
- } else
- return false;
- }
-
- @Override
- public boolean canPullUp()
- {
- if (getCount() == 0)
- {
-
- return true;
- } else if (getLastVisiblePosition() == (getCount() - 1))
- {
-
- if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null
- && getChildAt(
- getLastVisiblePosition()
- - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight())
- return true;
- }
- return false;
- }
-
- }
PullableGridView:
- package com.jingchen.pulltorefresh.pullableview;
-
- import android.content.Context;
- import android.util.AttributeSet;
- import android.widget.GridView;
-
- public class PullableGridView extends GridView implements Pullable
- {
-
- public PullableGridView(Context context)
- {
- super(context);
- }
-
- public PullableGridView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public PullableGridView(Context context, AttributeSet attrs, int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- public boolean canPullDown()
- {
- if (getCount() == 0)
- {
-
- return true;
- } else if (getFirstVisiblePosition() == 0
- && getChildAt(0).getTop() >= 0)
- {
-
- return true;
- } else
- return false;
- }
-
- @Override
- public boolean canPullUp()
- {
- if (getCount() == 0)
- {
-
- return true;
- } else if (getLastVisiblePosition() == (getCount() - 1))
- {
-
- if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null
- && getChildAt(
- getLastVisiblePosition()
- - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight())
- return true;
- }
- return false;
- }
-
- }
PullableScrollView:
- package com.jingchen.pulltorefresh.pullableview;
-
- import android.content.Context;
- import android.util.AttributeSet;
- import android.widget.ScrollView;
-
- public class PullableScrollView extends ScrollView implements Pullable
- {
-
- public PullableScrollView(Context context)
- {
- super(context);
- }
-
- public PullableScrollView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public PullableScrollView(Context context, AttributeSet attrs, int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- public boolean canPullDown()
- {
- if (getScrollY() == 0)
- return true;
- else
- return false;
- }
-
- @Override
- public boolean canPullUp()
- {
- if (getScrollY() >= (getChildAt(0).getHeight() - getMeasuredHeight()))
- return true;
- else
- return false;
- }
-
- }
PullableWebView:
- package com.jingchen.pulltorefresh.pullableview;
-
- import android.content.Context;
- import android.util.AttributeSet;
- import android.webkit.WebView;
-
- public class PullableWebView extends WebView implements Pullable
- {
-
- public PullableWebView(Context context)
- {
- super(context);
- }
-
- public PullableWebView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public PullableWebView(Context context, AttributeSet attrs, int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- public boolean canPullDown()
- {
- if (getScrollY() == 0)
- return true;
- else
- return false;
- }
-
- @Override
- public boolean canPullUp()
- {
- if (getScrollY() >= getContentHeight() * getScale()
- - getMeasuredHeight())
- return true;
- else
- return false;
- }
- }
ImageView和TextView就不贴了,我直接在方法里返回了true。 OK了,整个demo的代码有点多,就不贴了。