PullToRefreshListView上拉加载更多，下拉刷新

使用PullToRefreshListView实现上拉加载更多，下拉刷新。

源码如下：

首先在pullToRefresh包下创建PullableListView.java：

/pullToRefresh/PullableListView.java

import android.content.Context;
import android.util.AttributeSet;
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);
}

public boolean canPullDown()
{
if (getCount() == 0)
{
return true;
} else if (getFirstVisiblePosition() == 0
&& getChildAt(0).getTop() >= 0)
{
return true;
} else
return false;
}

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;
}
}

在同包下创建PullToRefreshLayout.java

/pullToRefresh/PullToRefreshLayout.java

import java.util.Timer;
import java.util.TimerTask;
import com.example.demo.R;
import android.content.Context;
import android.os.AsyncTask;
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;

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;
private Context mContext;

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();
requestLayout();
}
if (pullUpY > 0)
{
pullUpY = 0;
pullUpView.clearAnimation();
if (state != REFRESHING && state != LOADING)
changeState(INIT);
timer.cancel();
requestLayout();
}
Log.d("handle", "handle");
requestLayout();
if (pullDownY + Math.abs(pullUpY) == 0)
timer.cancel();
}

};

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)
{
mContext = 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;
}
if (pullDownY > 0)
{
new Handler()
{
@Override
public void handleMessage(Message msg)
{
changeState(DONE);
hide();
}
}.sendEmptyMessageDelayed(0, 1000);
} else
{
changeState(DONE);
hide();
}
}

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;
}
if (pullUpY < 0)
{
new Handler()
{
@Override
public void handleMessage(Message msg)
{
changeState(DONE);
hide();
}
}.sendEmptyMessageDelayed(0, 1000);
} else
{
changeState(DONE);
hide();
}
}

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 (pullDownY > 0
|| (((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 (pullUpY < 0
|| (((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))));
if (pullDownY > 0 || pullUpY < 0)
requestLayout();
if (pullDownY > 0)
{
if (pullDownY <= refreshDist
&& (state == RELEASE_TO_REFRESH || state == DONE))
{
changeState(INIT);
}
if (pullDownY >= refreshDist && state == INIT)
{
changeState(RELEASE_TO_REFRESH);
}
} else if (pullUpY < 0)
{
if (-pullUpY <= loadmoreDist
&& (state == RELEASE_TO_LOAD || state == DONE))
{
changeState(INIT);
}
if (-pullUpY >= loadmoreDist && state == INIT)
{
changeState(RELEASE_TO_LOAD);
}

}
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 class AutoRefreshAndLoadTask extends
AsyncTask<Integer, Float, String>
{

@Override
protected String doInBackground(Integer... params)
{
while (pullDownY < 4 / 3 * refreshDist)
{
pullDownY += MOVE_SPEED;
publishProgress(pullDownY);
try
{
Thread.sleep(params[0]);
} catch (InterruptedException e)
{
e.printStackTrace();
}
}
return null;
}

@Override
protected void onPostExecute(String result)
{
changeState(REFRESHING);
if (mListener != null)
mListener.onRefresh(PullToRefreshLayout.this);
hide();
}

@Override
protected void onProgressUpdate(Float... values)
{
if (pullDownY > refreshDist)
changeState(RELEASE_TO_REFRESH);
requestLayout();
}

}

public void autoRefresh()
{
AutoRefreshAndLoadTask task = new AutoRefreshAndLoadTask();
task.execute(20);
}

public void autoLoad()
{
pullUpY = -loadmoreDist;
requestLayout();
changeState(LOADING);
if (mListener != null)
mListener.onLoadMore(this);
}

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)
{
Log.d("Test", "Test");
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);
}

}

再在相同包下创建Pullable.java

public interface Pullable
{
boolean canPullDown();

boolean canPullUp();
}

布局中，创建如下xml文件：

res下创建anim，创建reverse_anim.xml：

/res/anim/reverse_anim.xml
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="100"
android:fillAfter="true"
android:fromDegrees="0"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="0"
android:toDegrees="180" >
</rotate>

res下anim中添加rotating.xml

旋转动画

/res/anim/rotating.xml
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="1500"
android:fillAfter="true"
android:fromDegrees="0"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="-1"
android:toDegrees="360" >
</rotate>

在String.xml中添加如下内容：

<string name="pull_to_refresh">下拉刷新</string>
<string name="release_to_refresh">释放立即刷新</string>
<string name="refreshing">正在刷新...</string>
<string name="refresh_succeed">刷新成功</string>
<string name="refresh_fail">刷新失败</string>
<string name="pullup_to_load">上拉加载更多</string>
<string name="release_to_load">释放立即加载</string>
<string name="loading">正在加载...</string>
<string name="load_succeed">加载成功</string>
<string name="load_fail">加载失败</string>

在res下layout下创建load_more.xml：
列表下部加载更多时显示的布局

/res/layout/load_more.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/loadmore_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/gray" >

<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="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/pullup_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="60dp"
android:background="@drawable/pullup_icon_big" />

<ImageView
android:id="@+id/loading_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="60dp"
android:background="@drawable/loading"
android:visibility="gone" />

<TextView
android:id="@+id/loadstate_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="@string/pullup_to_load"
android:textColor="@color/black"
android:textSize="16sp" />

<ImageView
android:id="@+id/loadstate_iv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginRight="8dp"
android:layout_toLeftOf="@id/loadstate_tv"
android:visibility="gone" />
</RelativeLayout>
</RelativeLayout>

</RelativeLayout>

在res中layout下，创建refresh_head.xml：列表中，下拉刷新时头部显示的布局

/res/layout/refresh_head.xml
<?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>

<com.baway.pullToRefresh.PullToRefreshLayout
android:id="@+id/layout"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<include layout="@layout/refresh_head" />

<com.baway.pullToRefresh.PullableListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:dividerHeight="10dp" >
</com.baway.pullToRefresh.PullableListView>

<include layout="@layout/load_more" />
</com.baway.pullToRefresh.PullToRefreshLayout>

至此所有的准备工作已经完成，所需要的资源文件已经创建完毕，在调用时，在布局中使用PullToRefreshListView或PullToRefrehGridView，包名＋类名。在代码中findViewById找到控件之后需要设置一个监听才能完成上拉加载更多，下拉刷新的效果。如下：

layout.setOnRefreshListener(new OnRefreshListener() {

public void onRefresh(PullToRefreshLayout pullToRefreshLayout) {

pullToRefreshLayout.refreshFinish(PullToRefreshLayout.SUCCEED);
}

public void onLoadMore(PullToRefreshLayout pullToRefreshLayout) {

pullToRefreshLayout.loadmoreFinish(PullToRefreshLayout.SUCCEED);

}
});

其中，调用loadmoreFinish方法表示加载更多完成，同样refreshFinish表示刷新完成，通知视图回归原位。