定位

代码！

<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:orientation="vertical" >

<com.example.pulldown.PullDownScrollView

android:id="@+id/refresh_root"

android:layout_width="fill_parent"

android:layout_height="0dip"

android:layout_weight="1"

android:background="#161616"

android:orientation="vertical" >

<ScrollView

android:id="@+id/scrollview"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:scrollbars="none" >

<LinearLayout

android:id="@+id/mainView"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:background="#1f1f1f"

android:orientation="vertical" >

<TextView

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dip"

android:gravity="center"

android:text="@string/hello_world"

android:textColor="@android:color/white"

android:textSize="18sp" />

<TextView

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dip"

android:gravity="center"

android:text="@string/hello_world"

android:textColor="@android:color/white"

android:textSize="18sp" />

<TextView

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dip"

android:gravity="center"

android:text="@string/hello_world"

android:textColor="@android:color/white"

android:textSize="18sp" />

<TextView

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dip"

android:gravity="center"

android:text="@string/hello_world"

android:textColor="@android:color/white"

android:textSize="18sp" />

</LinearLayout>

</ScrollView>

</com.example.pulldown.PullDownScrollView>

lt;/LinearLayout>

2.UI使用：

首先，Activity实现接口：

implements RefreshListener

部分代码如下：

Java代码收藏代码

package com.example.pulldown;

import com.example.pulldown.PullDownScrollView.RefreshListener;

import android.os.Bundle;

import android.os.Handler;

import android.app.Activity;

import android.view.Menu;

public class MainActivity extends Activity implements RefreshListener{

private PullDownScrollView mPullDownScrollView;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mPullDownScrollView = (PullDownScrollView) findViewById(R.id.refresh_root);

mPullDownScrollView.setRefreshListener(this);

mPullDownScrollView.setPullDownElastic(new PullDownElasticImp(this));

}

@Override

public void onRefresh(PullDownScrollView view) {

new Handler().postDelayed(new Runnable() {

@Override

public void run() {

// TODO Auto-generated method stub

mPullDownScrollView.finishRefresh("上次刷新时间:12:23");

}

}, 2000);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.activity_main, menu);

return true;

}

3.再来看看控件代码：

Java代码收藏代码

import android.content.Context;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import android.view.animation.LinearInterpolator;

import android.view.animation.RotateAnimation;

import android.widget.AbsListView;

import android.widget.LinearLayout;

import android.widget.ScrollView;

/**

* @author xwangly@163.com

* @date 2013-7-9

public class PullDownScrollView extends LinearLayout {

private static final String TAG = "PullDownScrollView";

private int refreshTargetTop = -60;

private int headContentHeight;

private RefreshListener refreshListener;

private RotateAnimation animation;

private RotateAnimation reverseAnimation;

private final static int RATIO = 2;

private int preY = 0;

private boolean isElastic = false;

private int startY;

private int state;

private String note_release_to_refresh = "松开更新";

private String note_pull_to_refresh = "下拉刷新";

private String note_refreshing = "正在更新...";

private IPullDownElastic mElastic;

public PullDownScrollView(Context context) {

super(context);

init();

}

public PullDownScrollView(Context context, AttributeSet attrs) {

super(context, attrs);

init();

}

private void init() {

animation = new RotateAnimation(0, -180,

RotateAnimation.RELATIVE_TO_SELF, 0.5f,

RotateAnimation.RELATIVE_TO_SELF, 0.5f);

animation.setInterpolator(new LinearInterpolator());

animation.setDuration(250);

animation.setFillAfter(true);

reverseAnimation = new RotateAnimation(-180, 0,

RotateAnimation.RELATIVE_TO_SELF, 0.5f,

RotateAnimation.RELATIVE_TO_SELF, 0.5f);

reverseAnimation.setInterpolator(new LinearInterpolator());

reverseAnimation.setDuration(200);

reverseAnimation.setFillAfter(true);

}

/**

* 刷新监听

* @param listener

public void setRefreshListener(RefreshListener listener) {

this.refreshListener = listener;

}

/**

* 下拉布局

* @param elastic

public void setPullDownElastic(IPullDownElastic elastic) {

mElastic = elastic;

headContentHeight = mElastic.getElasticHeight();

refreshTargetTop = - headContentHeight;

LayoutParams lp = new LinearLayout.LayoutParams(

LayoutParams.FILL_PARENT, headContentHeight);

lp.topMargin = refreshTargetTop;

addView(mElastic.getElasticLayout(), 0, lp);

}

/**

* 设置更新提示语

* @param pullToRefresh 下拉刷新提示语

* @param releaseToRefresh 松开刷新提示语

* @param refreshing 正在刷新提示语

public void setRefreshTips(String pullToRefresh, String releaseToRefresh, String refreshing) {

note_pull_to_refresh = pullToRefresh;

note_release_to_refresh = releaseToRefresh;

note_refreshing = refreshing;

}

* 该方法一般和ontouchEvent 一起用 (non-Javadoc)

* @see

* android.view.ViewGroup#onInterceptTouchEvent(android.view.MotionEvent)

@Override

public boolean onInterceptTouchEvent(MotionEvent ev) {

Logger.d(TAG, "onInterceptTouchEvent");

printMotionEvent(ev);

if (ev.getAction() == MotionEvent.ACTION_DOWN) {

preY = (int) ev.getY();

}

if (ev.getAction() == MotionEvent.ACTION_MOVE) {

Logger.d(TAG, "isElastic:" + isElastic + " canScroll:"+ canScroll() + " ev.getY() - preY:"+(ev.getY() - preY));

if (!isElastic && canScroll()

&& (int) ev.getY() - preY >= headContentHeight / (3*RATIO)

&& refreshListener != null && mElastic != null) {

isElastic = true;

startY = (int) ev.getY();

Logger.i(TAG, "在move时候记录下位置startY:" + startY);

return true;

}

return super.onInterceptTouchEvent(ev);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

Logger.d(TAG, "onTouchEvent");

printMotionEvent(event);

handleHeadElastic(event);

return super.onTouchEvent(event);

}

private void handleHeadElastic(MotionEvent event) {

if (refreshListener != null && mElastic != null) {

switch (event.getAction()) {

case MotionEvent.ACTION_DOWN:

Logger.i(TAG, "down");

break;

case MotionEvent.ACTION_UP:

Logger.i(TAG, "up");

if (state != IPullDownElastic.REFRESHING && isElastic) {

if (state == IPullDownElastic.DONE) {

// 什么都不做

setMargin(refreshTargetTop);

}

if (state == IPullDownElastic.PULL_To_REFRESH) {

state = IPullDownElastic.DONE;

setMargin(refreshTargetTop);

changeHeaderViewByState(state, false);

Logger.i(TAG, "由下拉刷新状态，到done状态");

}

if (state == IPullDownElastic.RELEASE_To_REFRESH) {

state = IPullDownElastic.REFRESHING;

setMargin(0);

changeHeaderViewByState(state, false);

onRefresh();

Logger.i(TAG, "由松开刷新状态，到done状态");

}

isElastic = false;

break;

case MotionEvent.ACTION_MOVE:

Logger.i(TAG, "move");

int tempY = (int) event.getY();

if (state != IPullDownElastic.REFRESHING && isElastic) {

// 可以松手去刷新了

if (state == IPullDownElastic.RELEASE_To_REFRESH) {

if (((tempY - startY) / RATIO < headContentHeight)

&& (tempY - startY) > 0) {

state = IPullDownElastic.PULL_To_REFRESH;

changeHeaderViewByState(state, true);

Logger.i(TAG, "由松开刷新状态转变到下拉刷新状态");

} else if (tempY - startY <= 0) {

state = IPullDownElastic.DONE;

changeHeaderViewByState(state, false);

Logger.i(TAG, "由松开刷新状态转变到done状态");

}

if (state == IPullDownElastic.DONE) {

if (tempY - startY > 0) {

state = IPullDownElastic.PULL_To_REFRESH;

changeHeaderViewByState(state, false);

}

if (state == IPullDownElastic.PULL_To_REFRESH) {

// 下拉到可以进入RELEASE_TO_REFRESH的状态

if ((tempY - startY) / RATIO >= headContentHeight) {

state = IPullDownElastic.RELEASE_To_REFRESH;

changeHeaderViewByState(state, false);

Logger.i(TAG, "由done或者下拉刷新状态转变到松开刷新");

} else if (tempY - startY <= 0) {

state = IPullDownElastic.DONE;

changeHeaderViewByState(state, false);

Logger.i(TAG, "由DOne或者下拉刷新状态转变到done状态");

}

if (tempY - startY > 0) {

setMargin((tempY - startY)/2 + refreshTargetTop);

}

break;

}

/**

private void setMargin(int top) {

LinearLayout.LayoutParams lp = (LayoutParams) mElastic.getElasticLayout()

.getLayoutParams();

lp.topMargin = top;

// 修改后刷新

mElastic.getElasticLayout().setLayoutParams(lp);

mElastic.getElasticLayout().invalidate();

}

private void changeHeaderViewByState(int state, boolean isBack) {

mElastic.changeElasticState(state, isBack);

switch (state) {

case IPullDownElastic.RELEASE_To_REFRESH:

mElastic.showArrow(View.VISIBLE);

mElastic.showProgressBar(View.GONE);

mElastic.showLastUpdate(View.VISIBLE);

mElastic.setTips(note_release_to_refresh);

mElastic.clearAnimation();

mElastic.startAnimation(animation);

Logger.i(TAG, "当前状态，松开刷新");

break;

case IPullDownElastic.PULL_To_REFRESH:

mElastic.showArrow(View.VISIBLE);

mElastic.showProgressBar(View.GONE);

mElastic.showLastUpdate(View.VISIBLE);

mElastic.setTips(note_pull_to_refresh);

mElastic.clearAnimation();

// 是由RELEASE_To_REFRESH状态转变来的

if (isBack) {

mElastic.startAnimation(reverseAnimation);

}

Logger.i(TAG, "当前状态，下拉刷新");

break;

case IPullDownElastic.REFRESHING:

mElastic.showArrow(View.GONE);

mElastic.showProgressBar(View.VISIBLE);

mElastic.showLastUpdate(View.GONE);

mElastic.setTips(note_refreshing);

mElastic.clearAnimation();

Logger.i(TAG, "当前状态,正在刷新...");

break;

case IPullDownElastic.DONE:

mElastic.showProgressBar(View.GONE);

mElastic.clearAnimation();

// arrowImageView.setImageResource(R.drawable.goicon);

// tipsTextview.setText("下拉刷新");

// lastUpdatedTextView.setVisibility(View.VISIBLE);

Logger.i(TAG, "当前状态，done");

break;

}

private void onRefresh() {

// downTextView.setVisibility(View.GONE);

// scroller.startScroll(0, i, 0, 0 - i);

// invalidate();

if (refreshListener != null) {

refreshListener.onRefresh(this);

}

/**

@Override

public void computeScroll() {

// if (scroller.computeScrollOffset()) {

// int i = this.scroller.getCurrY();

// LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) this.refreshView

// .getLayoutParams();

// int k = Math.max(i, refreshTargetTop);

// lp.topMargin = k;

// this.refreshView.setLayoutParams(lp);

// this.refreshView.invalidate();

// invalidate();

// }

}

/**

* 结束刷新事件，UI刷新完成后必须回调此方法

* @param text 一般传入：“上次更新时间:12:23”

public void finishRefresh(String text) {

if (mElastic == null) {

Logger.d(TAG, "finishRefresh mElastic:" + mElastic);

return;

}

state = IPullDownElastic.DONE;

mElastic.setLastUpdateText(text);

changeHeaderViewByState(state,false);

Logger.i(TAG, "执行了=====finishRefresh");

mElastic.showArrow(View.VISIBLE);

mElastic.showLastUpdate(View.VISIBLE);

setMargin(refreshTargetTop);

// scroller.startScroll(0, i, 0, refreshTargetTop);

// invalidate();

}

private boolean canScroll() {

View childView;

if (getChildCount() > 1) {

childView = this.getChildAt(1);

if (childView instanceof AbsListView) {

int top = ((AbsListView) childView).getChildAt(0).getTop();

int pad = ((AbsListView) childView).getListPaddingTop();

if ((Math.abs(top - pad)) < 3

&& ((AbsListView) childView).getFirstVisiblePosition() == 0) {

return true;

} else {

return false;

}

} else if (childView instanceof ScrollView) {

if (((ScrollView) childView).getScrollY() == 0) {

return true;

} else {

return false;

}

return canScroll(this);

}

/**

* 子类重写此方法可以兼容其它的子控件，目前只兼容AbsListView和ScrollView

* @param view

* @return

public boolean canScroll(PullDownScrollView view) {

return false;

}

private void printMotionEvent(MotionEvent event) {

switch (event.getAction()) {

case MotionEvent.ACTION_DOWN:

Logger.d(TAG, "down");

break;

case MotionEvent.ACTION_MOVE:

Logger.d(TAG, "move");

break;

case MotionEvent.ACTION_UP:

Logger.d(TAG, "up");

default:

break;

}

/**

* 刷新监听接口

public interface RefreshListener {

public void onRefresh(PullDownScrollView view);

}

4.接口：

Java代码收藏代码

import android.view.View;

import android.view.animation.Animation;

/**

* @author xwangly@163.com

* @date 2013-7-10

* 下拉控件接口

public interface IPullDownElastic {

public final static int RELEASE_To_REFRESH = 0;

public final static int PULL_To_REFRESH = 1;

public final static int REFRESHING = 2;

public final static int DONE = 3;

public View getElasticLayout();

public int getElasticHeight();

public void showArrow(int visibility);

public void startAnimation(Animation animation);

public void clearAnimation();

public void showProgressBar(int visibility);

public void setTips(String tips);

public void showLastUpdate(int visibility);

public void setLastUpdateText(String text);

/**

* 可以不用实现此方法，PullDownScrollView会处理ElasticLayout布局中的状态

* 如果需要特殊处理，可以实现此方法进行处理

* @param state @see RELEASE_To_REFRESH

* @param isBack 是否是松开回退

public void changeElasticState(int state, boolean isBack);

}

5.默认实现：

Java代码收藏代码

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.animation.Animation;

import android.widget.ImageView;

import android.widget.ProgressBar;

import android.widget.TextView;

/**

* @author xwangly@163.com

* @date 2013-7-10

* 默认下拉控件布局实现

public class PullDownElasticImp implements IPullDownElastic {

private View refreshView;

private ImageView arrowImageView;

private int headContentHeight;

private ProgressBar progressBar;

private TextView tipsTextview;

private TextView lastUpdatedTextView;

private Context mContext;

public PullDownElasticImp(Context context) {

mContext = context;

init();

}

private void init() {

// 刷新视图顶端的的view

refreshView = LayoutInflater.from(mContext).inflate(

R.layout.refresh_top_item, null);

// 指示器view

arrowImageView = (ImageView) refreshView

.findViewById(R.id.head_arrowImageView);

// 刷新bar

progressBar = (ProgressBar) refreshView

.findViewById(R.id.head_progressBar);

// 下拉显示text

tipsTextview = (TextView) refreshView.findViewById(R.id.refresh_hint);

// 下来显示时间

lastUpdatedTextView = (TextView) refreshView

.findViewById(R.id.refresh_time);

headContentHeight = Utils.dip2px(mContext, 50);

}

/**

* @return

@Override

public View getElasticLayout() {

return refreshView;

}

/**

* @return

@Override

public int getElasticHeight() {

return headContentHeight;

}

/**

* @param show

@Override

public void showArrow(int visibility) {

arrowImageView.setVisibility(visibility);

}

/**

* @param animation

@Override

public void startAnimation(Animation animation) {

arrowImageView.startAnimation(animation);

}

/**

@Override

public void clearAnimation() {

arrowImageView.clearAnimation();

}

/**

* @param show

@Override

public void showProgressBar(int visibility) {

progressBar.setVisibility(visibility);

}

/**

* @param tips

@Override

public void setTips(String tips) {

tipsTextview.setText(tips);

}

/**

* @param show

@Override

public void showLastUpdate(int visibility) {

lastUpdatedTextView.setVisibility(visibility);

}

/**

* @param text

public void setLastUpdateText(String text) {

lastUpdatedTextView.setText(text);

}

/**

* @param state

* @param isBack

@Override

public void changeElasticState(int state, boolean isBack) {

// TODO Auto-generated method stub

}

6.默认实现的布局：

Java代码收藏代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="-50.0dip"

android:orientation="vertical" >

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="0.0dip"

android:layout_weight="1.0"

android:gravity="center"

android:orientation="horizontal" >

<FrameLayout

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_centerVertical="true"

android:layout_marginLeft="30dip" >

<ImageView

android:id="@+id/head_arrowImageView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center"

android:src="@drawable/goicon" />

<ProgressBar

android:id="@+id/head_progressBar"

style="@android:style/Widget.ProgressBar.Small.Inverse"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center"

android:visibility="gone" />

</FrameLayout>

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center"

android:orientation="vertical" >

<TextView

android:id="@+id/refresh_hint"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="下拉刷新"

android:textColor="#f2f2f2"

android:textSize="16sp" />

<TextView

android:id="@+id/refresh_time"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="上次更新"

android:textColor="#b89766"

android:textSize="10sp" />

</LinearLayout>

6.图片资源：

@drawable/goicon

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