原文：Android下拉刷新，上拉加载。
源代码下载地址：http://www.zuidaima.com/share/1550463747574784.htm
Android列表的下拉刷新，上拉加载。
源码截图
package com.zuidaima.stay.pull.lib;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Color;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;
import android.widget.LinearLayout;
import com.stay.pull.R;
import com.stay.pull.lib.internal.LoadingLayout;
public abstract class PullToRefreshBase<T extends View> extends LinearLayout {
final class SmoothScrollRunnable implements Runnable {
static final int ANIMATION_DURATION_MS = 190;
static final int ANIMATION_FPS = 1000 / 60;
private final Interpolator interpolator;
private final int scrollToY;
private final int scrollFromY;
private final Handler handler;
private boolean continueRunning = true;
private long startTime = -1;
private int currentY = -1;
public SmoothScrollRunnable(Handler handler, int fromY, int toY) {
this.handler = handler;
this.scrollFromY = fromY;
this.scrollToY = toY;
this.interpolator = new AccelerateDecelerateInterpolator();
}
@Override
public void run() {
/**
* Only set startTime if this is the first time we're starting, else
* actually calculate the Y delta
*/
if (startTime == -1) {
startTime = System.currentTimeMillis();
} else {
/**
* We do do all calculations in long to reduce software float
* calculations. We use 1000 as it gives us good accuracy and
* small rounding errors
*/
long normalizedTime = (1000 * (System.currentTimeMillis() - startTime)) / ANIMATION_DURATION_MS;
normalizedTime = Math.max(Math.min(normalizedTime, 1000), 0);
final int deltaY = Math.round((scrollFromY - scrollToY)
* interpolator.getInterpolation(normalizedTime / 1000f));
this.currentY = scrollFromY - deltaY;
setHeaderScroll(currentY);
}
// If we're not at the target Y, keep going...
if (continueRunning && scrollToY != currentY) {
handler.postDelayed(this, ANIMATION_FPS);
}
}
public void stop() {
this.continueRunning = false;
this.handler.removeCallbacks(this);
}
};
// ===========================================================
// Constants
// ===========================================================
static final float FRICTION = 2.0f;
static final int PULL_TO_REFRESH = 0x0;
static final int RELEASE_TO_REFRESH = 0x1;
static final int REFRESHING = 0x2;
static final int MANUAL_REFRESHING = 0x3;
public static final int MODE_PULL_DOWN_TO_REFRESH = 0x1;
public static final int MODE_PULL_UP_TO_REFRESH = 0x2;
public static final int MODE_BOTH = 0x3;
// ===========================================================
// Fields
// ===========================================================
private int touchSlop;
private float initialMotionY;
private float lastMotionX;
private float lastMotionY;
private boolean isBeingDragged = false;
private int state = PULL_TO_REFRESH;
private int mode = MODE_PULL_DOWN_TO_REFRESH;
private int currentMode;
private boolean disableScrollingWhileRefreshing = true;
T refreshableView;
private boolean isPullToRefreshEnabled = true;
private LoadingLayout headerLayout;
private LoadingLayout footerLayout;
private int headerHeight;
private final Handler handler = new Handler();
private OnRefreshListener onRefreshListener;
private SmoothScrollRunnable currentSmoothScrollRunnable;
// ===========================================================
// Constructors
// ===========================================================
public PullToRefreshBase(Context context) {
super(context);
init(context, null);
}
public PullToRefreshBase(Context context, int mode) {
super(context);
this.mode = mode;
init(context, null);
}
public PullToRefreshBase(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
// ===========================================================
// Getter & Setter
// ===========================================================
/**
* Deprecated. Use {@link #getRefreshableView()} from now on.
*
* @deprecated
* @return The Refreshable View which is currently wrapped
*/
public final T getAdapterView() {
return refreshableView;
}
/**
* Get the Wrapped Refreshable View. Anything returned here has already been
* added to the content view.
*
* @return The View which is currently wrapped
*/
public final T getRefreshableView() {
return refreshableView;
}
/**
* Whether Pull-to-Refresh is enabled
*
* @return enabled
*/
public final boolean isPullToRefreshEnabled() {
return isPullToRefreshEnabled;
}
/**
* Returns whether the widget has disabled scrolling on the Refreshable View
* while refreshing.
*
* @param true if the widget has disabled scrolling while refreshing
*/
public final boolean isDisableScrollingWhileRefreshing() {
return disableScrollingWhileRefreshing;
}
/**
* Returns whether the Widget is currently in the Refreshing state
*
* @return true if the Widget is currently refreshing
*/
public final boolean isRefreshing() {
return state == REFRESHING || state == MANUAL_REFRESHING;
}
/**
* By default the Widget disabled scrolling on the Refreshable View while
* refreshing. This method can change this behaviour.
*
* @param disableScrollingWhileRefreshing
* - true if you want to disable scrolling while refreshing
*/
public final void setDisableScrollingWhileRefreshing(boolean disableScrollingWhileRefreshing) {
this.disableScrollingWhileRefreshing = disableScrollingWhileRefreshing;
}
/**
* Mark the current Refresh as complete. Will Reset the UI and hide the
* Refreshing View
*/
public final void onRefreshComplete() {
if (state != PULL_TO_REFRESH) {
resetHeader();
}
}
/**
* Set OnRefreshListener for the Widget
*
* @param listener
* - Listener to be used when the Widget is set to Refresh
*/
public final void setOnRefreshListener(OnRefreshListener listener) {
onRefreshListener = listener;
}
/**
* A mutator to enable/disable Pull-to-Refresh for the current View
*
* @param enable
* Whether Pull-To-Refresh should be used
*/
public final void setPullToRefreshEnabled(boolean enable) {
this.isPullToRefreshEnabled = enable;
}
/**
* Set Text to show when the Widget is being pulled, and will refresh when
* released
*
* @param releaseLabel
* - String to display
*/
public void setReleaseLabel(String releaseLabel) {
if (null != headerLayout) {
headerLayout.setReleaseLabel(releaseLabel);
}
if (null != footerLayout) {
footerLayout.setReleaseLabel(releaseLabel);
}
}
/**
* Set Text to show when the Widget is being Pulled
*
* @param pullLabel
* - String to display
*/
public void setPullLabel(String pullLabel) {
if (null != headerLayout) {
headerLayout.setPullLabel(pullLabel);
}
if (null != footerLayout) {
footerLayout.setPullLabel(pullLabel);
}
}
/**
* Set Text to show when the Widget is refreshing
*
* @param refreshingLabel
* - String to display
*/
public void setRefreshingLabel(String refreshingLabel) {
if (null != headerLayout) {
headerLayout.setRefreshingLabel(refreshingLabel);
}
if (null != footerLayout) {
footerLayout.setRefreshingLabel(refreshingLabel);
}
}
public final void setRefreshing() {
this.setRefreshing(true);
}
/**
* Sets the Widget to be in the refresh state. The UI will be updated to
* show the 'Refreshing' view.
*
* @param doScroll
* - true if you want to force a scroll to the Refreshing view.
*/
public final void setRefreshing(boolean doScroll) {
if (!isRefreshing()) {
setRefreshingInternal(doScroll);
state = MANUAL_REFRESHING;
}
}
public final boolean hasPullFromTop() {
return currentMode != MODE_PULL_UP_TO_REFRESH;
}
// ===========================================================
// Methods for/from SuperClass/Interfaces
// ===========================================================
@Override
public final boolean onTouchEvent(MotionEvent event) {
if (!isPullToRefreshEnabled) {
return false;
}
if (isRefreshing() && disableScrollingWhileRefreshing) {
return true;
}
if (event.getAction() == MotionEvent.ACTION_DOWN && event.getEdgeFlags() != 0) {
return false;
}
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE: {
if (isBeingDragged) {
lastMotionY = event.getY();
this.pullEvent();
return true;
}
break;
}
case MotionEvent.ACTION_DOWN: {
if (isReadyForPull()) {
lastMotionY = initialMotionY = event.getY();
return true;
}
break;
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP: {
if (isBeingDragged) {
isBeingDragged = false;
if (state == RELEASE_TO_REFRESH && null != onRefreshListener) {
setRefreshingInternal(true);
onRefreshListener.onRefresh();
} else {
smoothScrollTo(0);
}
return true;
}
break;
}
}
return false;
}
@Override
public final boolean onInterceptTouchEvent(MotionEvent event) {
if (!isPullToRefreshEnabled) {
return false;
}
if (isRefreshing() && disableScrollingWhileRefreshing) {
return true;
}
final int action = event.getAction();
if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {
isBeingDragged = false;
return false;
}
if (action != MotionEvent.ACTION_DOWN && isBeingDragged) {
return true;
}
switch (action) {
case MotionEvent.ACTION_MOVE: {
if (isReadyForPull()) {
final float y = event.getY();
final float dy = y - lastMotionY;
final float yDiff = Math.abs(dy);
final float xDiff = Math.abs(event.getX() - lastMotionX);
if (yDiff > touchSlop && yDiff > xDiff) {
if ((mode == MODE_PULL_DOWN_TO_REFRESH || mode == MODE_BOTH) && dy >= 0.0001f
&& isReadyForPullDown()) {
lastMotionY = y;
isBeingDragged = true;
if (mode == MODE_BOTH) {
currentMode = MODE_PULL_DOWN_TO_REFRESH;
}
} else if ((mode == MODE_PULL_UP_TO_REFRESH || mode == MODE_BOTH) && dy <= 0.0001f
&& isReadyForPullUp()) {
lastMotionY = y;
isBeingDragged = true;
if (mode == MODE_BOTH) {
currentMode = MODE_PULL_UP_TO_REFRESH;
}
}
}
}
break;
}
case MotionEvent.ACTION_DOWN: {
if (isReadyForPull()) {
lastMotionY = initialMotionY = event.getY();
lastMotionX = event.getX();
isBeingDragged = false;
}
break;
}
}
return isBeingDragged;
}
protected void addRefreshableView(Context context, T refreshableView) {
addView(refreshableView, new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, 1.0f));
}
/**
* This is implemented by derived classes to return the created View. If you
* need to use a custom View (such as a custom ListView), override this
* method and return an instance of your custom class.
*
* Be sure to set the ID of the view in this method, especially if you're
* using a ListActivity or ListFragment.
*
* @param context
* @param attrs
* AttributeSet from wrapped class. Means that anything you
* include in the XML layout declaration will be routed to the
* created View
* @return New instance of the Refreshable View
*/
protected abstract T createRefreshableView(Context context, AttributeSet attrs);
protected final int getCurrentMode() {
return currentMode;
}
protected final LoadingLayout getFooterLayout() {
return footerLayout;
}
protected final LoadingLayout getHeaderLayout() {
return headerLayout;
}
protected final int getHeaderHeight() {
return headerHeight;
}
protected final int getMode() {
return mode;
}
/**
* Implemented by derived class to return whether the View is in a state
* where the user can Pull to Refresh by scrolling down.
*
* @return true if the View is currently the correct state (for example, top
* of a ListView)
*/
protected abstract boolean isReadyForPullDown();
/**
* Implemented by derived class to return whether the View is in a state
* where the user can Pull to Refresh by scrolling up.
*
* @return true if the View is currently in the correct state (for example,
* bottom of a ListView)
* @author www.zuidaima.com
*/
protected abstract boolean isReadyForPullUp();
// ===========================================================
// Methods
// ===========================================================
protected void resetHeader() {
state = PULL_TO_REFRESH;
isBeingDragged = false;
if (null != headerLayout) {
headerLayout.reset();
}
if (null != footerLayout) {
footerLayout.reset();
}
smoothScrollTo(0);
}
protected void setRefreshingInternal(boolean doScroll) {
state = REFRESHING;
if (null != headerLayout) {
headerLayout.refreshing();
}
if (null != footerLayout) {
footerLayout.refreshing();
}
if (doScroll) {
smoothScrollTo(currentMode == MODE_PULL_DOWN_TO_REFRESH ? -headerHeight : headerHeight);
}
}
protected final void setHeaderScroll(int y) {
scrollTo(0, y);
}
protected final void smoothScrollTo(int y) {
if (null != currentSmoothScrollRunnable) {
currentSmoothScrollRunnable.stop();
}
if (this.getScrollY() != y) {
this.currentSmoothScrollRunnable = new SmoothScrollRunnable(handler, getScrollY(), y);
handler.post(currentSmoothScrollRunnable);
}
}
private void init(Context context, AttributeSet attrs) {
setOrientation(LinearLayout.VERTICAL);
touchSlop = ViewConfiguration.getTouchSlop();
// Styleables from XML
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PullToRefresh);
if (a.hasValue(R.styleable.PullToRefresh_mode)) {
mode = a.getInteger(R.styleable.PullToRefresh_mode, MODE_PULL_DOWN_TO_REFRESH);
}
// Refreshable View
// By passing the attrs, we can add ListView/GridView params via XML
refreshableView = this.createRefreshableView(context, attrs);
this.addRefreshableView(context, refreshableView);
// Loading View Strings
String pullLabel = context.getString(R.string.pull_to_refresh_pull_label);
String refreshingLabel = context.getString(R.string.pull_to_refresh_refreshing_label);
String releaseLabel = context.getString(R.string.pull_to_refresh_release_label);
// Add Loading Views
if (mode == MODE_PULL_DOWN_TO_REFRESH || mode == MODE_BOTH) {
headerLayout = new LoadingLayout(context, MODE_PULL_DOWN_TO_REFRESH, releaseLabel, pullLabel,
refreshingLabel);
addView(headerLayout, 0, new LinearLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
measureView(headerLayout);
headerHeight = headerLayout.getMeasuredHeight();
}
if (mode == MODE_PULL_UP_TO_REFRESH || mode == MODE_BOTH) {
footerLayout = new LoadingLayout(context, MODE_PULL_UP_TO_REFRESH, releaseLabel, pullLabel, refreshingLabel);
addView(footerLayout, new LinearLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
measureView(footerLayout);
headerHeight = footerLayout.getMeasuredHeight();
}
// Styleables from XML
if (a.hasValue(R.styleable.PullToRefresh_headerTextColor)) {
final int color = a.getColor(R.styleable.PullToRefresh_headerTextColor, Color.BLACK);
if (null != headerLayout) {
headerLayout.setTextColor(color);
}
if (null != footerLayout) {
footerLayout.setTextColor(color);
}
}
if (a.hasValue(R.styleable.PullToRefresh_headerBackground)) {
this.setBackgroundResource(a.getResourceId(R.styleable.PullToRefresh_headerBackground, Color.WHITE));
}
if (a.hasValue(R.styleable.PullToRefresh_adapterViewBackground)) {
refreshableView.setBackgroundResource(a.getResourceId(R.styleable.PullToRefresh_adapterViewBackground,
Color.WHITE));
}
a.recycle();
// Hide Loading Views
switch (mode) {
case MODE_BOTH:
setPadding(0, -headerHeight, 0, -headerHeight);
break;
case MODE_PULL_UP_TO_REFRESH:
setPadding(0, 0, 0, -headerHeight);
break;
case MODE_PULL_DOWN_TO_REFRESH:
default:
setPadding(0, -headerHeight, 0, 0);
break;
}
// If we're not using MODE_BOTH, then just set currentMode to current
// mode
if (mode != MODE_BOTH) {
currentMode = mode;
}
}
private void measureView(View child) {
ViewGroup.LayoutParams p = child.getLayoutParams();
if (p == null) {
p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
}
int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
}
/**
* Actions a Pull Event
*
* @return true if the Event has been handled, false if there has been no
* change
*/
private boolean pullEvent() {
final int newHeight;
final int oldHeight = this.getScrollY();
switch (currentMode) {
case MODE_PULL_UP_TO_REFRESH:
newHeight = Math.round(Math.max(initialMotionY - lastMotionY, 0) / FRICTION);
// newHeight = Math.round((initialMotionY - lastMotionY) / FRICTION);
break;
case MODE_PULL_DOWN_TO_REFRESH:
default:
newHeight = Math.round(Math.min(initialMotionY - lastMotionY, 0) / FRICTION);
// newHeight = Math.round((initialMotionY - lastMotionY) / FRICTION);
break;
}
setHeaderScroll(newHeight);
if (newHeight != 0) {
if (state == PULL_TO_REFRESH && headerHeight < Math.abs(newHeight)) {
state = RELEASE_TO_REFRESH;
switch (currentMode) {
case MODE_PULL_UP_TO_REFRESH:
footerLayout.releaseToRefresh();
break;
case MODE_PULL_DOWN_TO_REFRESH:
headerLayout.releaseToRefresh();
break;
}
return true;
} else if (state == RELEASE_TO_REFRESH && headerHeight >= Math.abs(newHeight)) {
state = PULL_TO_REFRESH;
switch (currentMode) {
case MODE_PULL_UP_TO_REFRESH:
footerLayout.pullToRefresh();
break;
case MODE_PULL_DOWN_TO_REFRESH:
headerLayout.pullToRefresh();
break;
}
return true;
}
}
return oldHeight != newHeight;
}
private boolean isReadyForPull() {
switch (mode) {
case MODE_PULL_DOWN_TO_REFRESH:
return isReadyForPullDown();
case MODE_PULL_UP_TO_REFRESH:
return isReadyForPullUp();
case MODE_BOTH:
return isReadyForPullUp() || isReadyForPullDown();
}
return false;
}
// ===========================================================
// Inner and Anonymous Classes
// ===========================================================
public static interface OnRefreshListener {
public void onRefresh();
}
public static interface OnLastItemVisibleListener {
public void onLastItemVisible();
}
@Override
public void setLongClickable(boolean longClickable) {
getRefreshableView().setLongClickable(longClickable);
}
}