GridView基于pulltorefresh实现下拉刷新 上拉加载更多功能，flutter文档
*/
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.
-
@return 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();
if (onShowLayoutListener != null) {
onShowLayoutListener.onDismiss();
}
}
}
/**
-
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;
}
/**
-
auto load headerLayout to refresh
-
@param listener
*/
public final void setFirstAutoPullUpToRefresh(OnRefreshListener listener) {
setRefreshingInternal(true, MODE_PULL_DOWN_TO_REFRESH);
listener.onRefresh(MODE_PULL_DOWN_TO_REFRESH);
}
/**
-
set refreshLable , default use null
-
@param pullLabel
-
@param releaseLabel
-
@param refreshingLabel
*/
public void setRefreshLabel(String pullLabel, String releaseLabel,
String refreshingLabel) {
if (pullLabel != null) {
setPullLabel(pullLabel);
}
if (releaseLabel != null) {
setReleaseLabel(releaseLabel);
}
if (refreshingLabel != null) {
setRefreshingLabel(refreshingLabel);
}
}
/**
-
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
*/
private 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
*/
private 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
*/
private 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) {
if (Math.abs(event.getY() - downLocation) > 5
&& onShowLayoutListener != null) {
onShowLayoutListener.onShow();
}
lastMotionY = event.getY();
this.pullEvent();
return true;
}
break;
}
case MotionEvent.ACTION_DOWN: {
if (isReadyForPull()) {
downLocation = event.getY();
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(currentMode);
} else {
smoothScrollTo(0);
if (onShowLayoutListener != null) {
onShowLayoutListener.onDismiss();
}
}
return true;
}
break;
}
}
return false;
}
// remeber to down location
private float downLocation = 0;
@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;
}
case MotionEvent.ACTION_UP:
break;
}
setRefreshLabel(currentMode);
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);
public 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)
*/
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);
}
/**
-
unless special requirements to call the method ,default call the method
-
{@link #setRefreshingInternal(boolean doScroll)}
-
@param doScroll
-
@param mode
*/
protected void setRefreshingInternal(boolean doScroll, int mode) {
state = REFRESHING;
setRefreshLabel(mode);
if (null != headerLayout) {
headerLayout.refreshing();
}
if (doScroll) {
-
smoothScrollTo(mode == MODE_PULL_DOWN_TO_REFRESH ? -headerHeight
- headerHeight);
}
}
/**
-
set last refresh time
-
@param time
*/
public void setRefreshTime(String time) {
TextView mHeaderTimeView = (TextView) headerLayout
.findViewById(R.id.xlistview_header_time);
mHeaderTimeView.setText(time);
}
public void setRefreshTime(long time){
TextView mHeaderTimeView = (TextView) headerLayout
.findViewById(R.id.xlistview_header_time);
mHeaderTimeView.setText(TimeUtil.getChatTime(time));
}
protected void setRefreshingInternal(boolean doScroll) {
state = REFRESHING;
setRefreshLabel(currentMode);
if (null != footerLayout) {
footerLayout.refreshing();
}
if (null != headerLayout) {
headerLayout.refreshing();
}
if (doScroll) {
-
smoothScrollTo(currentMode == MODE_PULL_DOWN_TO_REFRESH ? -headerHeight
- headerHeight);
}
}
private void setRefreshLabel(int mode) {
if (mode == MODE_PULL_DOWN_TO_REFRESH) {
setRefreshLabel(“涓嬫媺鍒锋柊”, “閲婃斁绔嬪嵆鍒锋柊”, “姝ｅ湪鍒锋柊”);
}
if (mode == MODE_PULL_UP_TO_REFRESH) {
setRefreshLabel(“涓婃媺鑾峰彇鏇村”, “鏉惧紑鏄剧ず鏇村”, “姝ｅ湪鍔犺浇”);
}
}
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);
}
}
public void init(int mode) {
// 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 (null != headerLayout) {
// headerLayout.setTextColor(Color.BLACK);
}
if (null != footerLayout) {
// footerLayout.setTextColor(Color.BLACK);
}
// 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;
}
this.mode = mode;
}
private void init(Context context, AttributeSet attrs) {
this.context = context;
setOrientation(LinearLayout.VERTICAL);
touchSlop = ViewConfiguration.getTouchSlop();
// Refreshable View
// By passing the attrs, we can add ListView/GridView params via XML
refreshableView = this.createRefreshableView(context, attrs);
this.addRefreshableView(context, refreshableView);
}
private Context context;
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) {
点击这里免费领取吧！
MotionY, 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) {
[外链图片转存中…(img-t9XEDAV5-1646142864096)]
[外链图片转存中…(img-L7EVMdG9-1646142864098)]
点击这里免费领取吧！
开源鸿蒙跨平台开发社区汇聚开发者与厂商，共建“一次开发，多端部署”的开源生态，致力于降低跨端开发门槛，推动万物智联创新。
更多推荐
0
0- 0
已为社区贡献11条内容
所有评论(0)