ListView下拉刷新、上拉載入更多之封裝改進

時間 2019-11-07

標籤 listview 下拉刷新載入更多封裝改進欄目軟件設計简体版

原文原文鏈接

代碼以下：
java

XListView：android

/** ide

* @file XListView.java 佈局

* @package me.maxwin.view post

* @create Mar 18, 2012 6:28:41 PM this

* @author Maxwin spa

* @description An ListView support (a) Pull down to refresh, (b) Pull up to load more. .net

* Implement IXListViewListener, and see stopRefresh() / stopLoadMore(). code

*/ orm

package com.home.view;

import android.content.Context;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import android.view.ViewTreeObserver.OnGlobalLayoutListener;

import android.view.animation.DecelerateInterpolator;

import android.widget.AbsListView;

import android.widget.AbsListView.OnScrollListener;

import android.widget.ListAdapter;

import android.widget.ListView;

import android.widget.RelativeLayout;

import android.widget.Scroller;

import android.widget.TextView;

public class XListView extends ListView implements OnScrollListener {

private float mLastY = -1; // save event y

private Scroller mScroller; // used for scroll back

private OnScrollListener mScrollListener; // user's scroll listener

// the interface to trigger refresh and load more.

private IXListViewListener mListViewListener;

// -- header view

private XListViewHeader mHeaderView;

// header view content, use it to calculate the Header's height. And hide it

// when disable pull refresh.

private RelativeLayout mHeaderViewContent;

private TextView mHeaderTimeView;

private int mHeaderViewHeight; // header view's height

private boolean mEnablePullRefresh = true;

private boolean mPullRefreshing = false; // is refreashing.

// -- footer view

private XListViewFooter mFooterView;

private boolean mEnablePullLoad;

private boolean mPullLoading;

private boolean mIsFooterReady = false;

// total list items, used to detect is at the bottom of listview.

private int mTotalItemCount;

// for mScroller, scroll back from header or footer.

private int mScrollBack;

private final static int SCROLLBACK_HEADER = 0;

private final static int SCROLLBACK_FOOTER = 1;

private final static int SCROLL_DURATION = 400; // scroll back duration

private final static int PULL_LOAD_MORE_DELTA = 50; // when pull up >= 50px

// at bottom, trigger

// load more.

private final static float OFFSET_RADIO = 1.8f; // support iOS like pull

// feature.

/**

* @param context

*/

public XListView(Context context) {

super(context);

initWithContext(context);

}

public XListView(Context context, AttributeSet attrs) {

super(context, attrs);

initWithContext(context);

}

public XListView(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

initWithContext(context);

}

private void initWithContext(Context context) {

mScroller = new Scroller(context, new DecelerateInterpolator());

// XListView need the scroll event, and it will dispatch the event to

// user's listener (as a proxy).

super.setOnScrollListener(this);

// init header view

mHeaderView = new XListViewHeader(context);

mHeaderViewContent = (RelativeLayout) mHeaderView

.findViewById(XListViewHeader.RELAYOUT_ID);

mHeaderTimeView = (TextView) mHeaderView

.findViewById(XListViewHeader.HEAD_TIME_VIEW_ID);

addHeaderView(mHeaderView);

// init footer view

mFooterView = new XListViewFooter(context);

// init header height

mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(

new OnGlobalLayoutListener() {

@Override

public void onGlobalLayout() {

mHeaderViewHeight = mHeaderViewContent.getHeight();

getViewTreeObserver()

.removeGlobalOnLayoutListener(this);

}

});

}

@Override

public void setAdapter(ListAdapter adapter) {

// make sure XListViewFooter is the last footer view, and only add once.

if (mIsFooterReady == false) {

mIsFooterReady = true;

addFooterView(mFooterView);

}

super.setAdapter(adapter);

}

/**

* enable or disable pull down refresh feature.

*

* @param enable

*/

public void setPullRefreshEnable(boolean enable) {

mEnablePullRefresh = enable;

if (!mEnablePullRefresh) { // disable, hide the content

mHeaderViewContent.setVisibility(View.INVISIBLE);

} else {

mHeaderViewContent.setVisibility(View.VISIBLE);

}

}

/**

* enable or disable pull up load more feature.

*

* @param enable

*/

public void setPullLoadEnable(boolean enable) {

mEnablePullLoad = enable;

if (!mEnablePullLoad) {

mFooterView.hide();

mFooterView.setOnClickListener(null);

} else {

mPullLoading = false;

mFooterView.show();

mFooterView.setState(XListViewFooter.STATE_NORMAL);

// both "pull up" and "click" will invoke load more.

mFooterView.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

startLoadMore();

}

});

}

}

/**

* stop refresh, reset header view.

*/

public void stopRefresh() {

if (mPullRefreshing == true) {

mPullRefreshing = false;

resetHeaderHeight();

}

}

/**

* stop load more, reset footer view.

*/

public void stopLoadMore() {

if (mPullLoading == true) {

mPullLoading = false;

mFooterView.setState(XListViewFooter.STATE_NORMAL);

}

}

/**

* set last refresh time

*

* @param time

*/

public void setRefreshTime(String time) {

mHeaderTimeView.setText(time);

}

private void invokeOnScrolling() {

if (mScrollListener instanceof OnXScrollListener) {

OnXScrollListener l = (OnXScrollListener) mScrollListener;

l.onXScrolling(this);

}

}

private void updateHeaderHeight(float delta) {

mHeaderView.setVisiableHeight((int) delta

+ mHeaderView.getVisiableHeight());

if (mEnablePullRefresh && !mPullRefreshing) { // 未處於刷新狀態，更新箭頭

if (mHeaderView.getVisiableHeight() > mHeaderViewHeight) {

mHeaderView.setState(XListViewHeader.STATE_READY);

} else {

mHeaderView.setState(XListViewHeader.STATE_NORMAL);

}

}

setSelection(0); // scroll to top each time

}

/**

* reset header view's height.

*/

private void resetHeaderHeight() {

int height = mHeaderView.getVisiableHeight();

if (height == 0) // not visible.

return;

// refreshing and header isn't shown fully. do nothing.

if (mPullRefreshing && height <= mHeaderViewHeight) {

return;

}

int finalHeight = 0; // default: scroll back to dismiss header.

// is refreshing, just scroll back to show all the header.

if (mPullRefreshing && height > mHeaderViewHeight) {

finalHeight = mHeaderViewHeight;

}

mScrollBack = SCROLLBACK_HEADER;

mScroller.startScroll(0, height, 0, finalHeight - height,

SCROLL_DURATION);

// trigger computeScroll

invalidate();

}

private void updateFooterHeight(float delta) {

int height = mFooterView.getBottomMargin() + (int) delta;

if (mEnablePullLoad && !mPullLoading) {

if (height > PULL_LOAD_MORE_DELTA) { // height enough to invoke load

// more.

mFooterView.setState(XListViewFooter.STATE_READY);

} else {

mFooterView.setState(XListViewFooter.STATE_NORMAL);

}

}

mFooterView.setBottomMargin(height);

// setSelection(mTotalItemCount - 1); // scroll to bottom

}

private void resetFooterHeight() {

int bottomMargin = mFooterView.getBottomMargin();

if (bottomMargin > 0) {

mScrollBack = SCROLLBACK_FOOTER;

mScroller.startScroll(0, bottomMargin, 0, -bottomMargin,

SCROLL_DURATION);

invalidate();

}

}

private void startLoadMore() {

mPullLoading = true;

mFooterView.setState(XListViewFooter.STATE_LOADING);

if (mListViewListener != null) {

mListViewListener.onLoadMore();

}

}

@Override

public boolean onTouchEvent(MotionEvent ev) {

if (mLastY == -1) {

mLastY = ev.getRawY();

}

switch (ev.getAction()) {

case MotionEvent.ACTION_DOWN:

mLastY = ev.getRawY();

break;

case MotionEvent.ACTION_MOVE:

final float deltaY = ev.getRawY() - mLastY;

mLastY = ev.getRawY();

System.out.println("數據監測：" + getFirstVisiblePosition() + "---->"

+ getLastVisiblePosition());

if (getFirstVisiblePosition() == 0

&& (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)) {

// the first item is showing, header has shown or pull down.

updateHeaderHeight(deltaY / OFFSET_RADIO);

invokeOnScrolling();

} else if (getLastVisiblePosition() == mTotalItemCount - 1

&& (mFooterView.getBottomMargin() > 0 || deltaY < 0)) {

// last item, already pulled up or want to pull up.

updateFooterHeight(-deltaY / OFFSET_RADIO);

}

break;

default:

mLastY = -1; // reset

if (getFirstVisiblePosition() == 0) {

// invoke refresh

if (mEnablePullRefresh

&& mHeaderView.getVisiableHeight() > mHeaderViewHeight) {

mPullRefreshing = true;

mHeaderView.setState(XListViewHeader.STATE_REFRESHING);

if (mListViewListener != null) {

mListViewListener.onRefresh();

}

}

resetHeaderHeight();

}

if (getLastVisiblePosition() == mTotalItemCount - 1) {

// invoke load more.

if (mEnablePullLoad

&& mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA) {

startLoadMore();

}

resetFooterHeight();

}

break;

}

return super.onTouchEvent(ev);

}

@Override

public void computeScroll() {

if (mScroller.computeScrollOffset()) {

if (mScrollBack == SCROLLBACK_HEADER) {

mHeaderView.setVisiableHeight(mScroller.getCurrY());

} else {

mFooterView.setBottomMargin(mScroller.getCurrY());

}

postInvalidate();

invokeOnScrolling();

}

super.computeScroll();

}

@Override

public void setOnScrollListener(OnScrollListener l) {

mScrollListener = l;

}

@Override

public void onScrollStateChanged(AbsListView view, int scrollState) {

if (mScrollListener != null) {

mScrollListener.onScrollStateChanged(view, scrollState);

}

}

@Override

public void onScroll(AbsListView view, int firstVisibleItem,

int visibleItemCount, int totalItemCount) {

// send to user's listener

mTotalItemCount = totalItemCount;

if (mScrollListener != null) {

mScrollListener.onScroll(view, firstVisibleItem, visibleItemCount,

totalItemCount);

}

}

public void setXListViewListener(IXListViewListener l) {

mListViewListener = l;

}

/**

* you can listen ListView.OnScrollListener or this one. it will invoke

* onXScrolling when header/footer scroll back.

*/

public interface OnXScrollListener extends OnScrollListener {

public void onXScrolling(View view);

}

/**

* implements this interface to get refresh/load more event.

*/

public interface IXListViewListener {

public void onRefresh();

public void onLoadMore();

}

}

XListViewFooter：

package com.home.view;

import android.content.Context;

import android.util.AttributeSet;

import android.view.Gravity;

import android.view.View;

import android.widget.LinearLayout;

import android.widget.ProgressBar;

import android.widget.RelativeLayout;

import android.widget.TextView;

public class XListViewFooter extends LinearLayout {

public final static int STATE_NORMAL = 0;

public final static int STATE_READY = 1;

public final static int STATE_LOADING = 2;

private Context mContext;

private RelativeLayout mContentView;

private ProgressBar mProgressBar;

private TextView mHintView;

public XListViewFooter(Context context) {

super(context);

initView(context);

}

public XListViewFooter(Context context, AttributeSet attrs) {

super(context, attrs);

initView(context);

}

public void setState(int state) {

mHintView.setVisibility(View.INVISIBLE);

mProgressBar.setVisibility(View.INVISIBLE);

mHintView.setVisibility(View.INVISIBLE);

if (state == STATE_READY) {

mHintView.setVisibility(View.VISIBLE);

mHintView.setText("鬆開載入更多");

} else if (state == STATE_LOADING) {

mProgressBar.setVisibility(View.VISIBLE);

} else {

mHintView.setVisibility(View.VISIBLE);

mHintView.setText("查看更多");

}

}

public void setBottomMargin(int height) {

if (height < 0)

return;

LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContentView

.getLayoutParams();

lp.bottomMargin = height;

mContentView.setLayoutParams(lp);

}

public int getBottomMargin() {

LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContentView

.getLayoutParams();

return lp.bottomMargin;

}

/**

* normal status

*/

public void normal() {

mHintView.setVisibility(View.VISIBLE);

mProgressBar.setVisibility(View.GONE);

}

/**

* loading status

*/

public void loading() {

mHintView.setVisibility(View.GONE);

mProgressBar.setVisibility(View.VISIBLE);

}

/**

* hide footer when disable pull load more

*/

public void hide() {

LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContentView

.getLayoutParams();

lp.height = 0;

mContentView.setLayoutParams(lp);

}

/**

* show footer

*/

public void show() {

LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContentView

.getLayoutParams();

lp.height = LayoutParams.WRAP_CONTENT;

mContentView.setLayoutParams(lp);

}

private void initView(Context context) {

mContext = context;

// 根佈局

LinearLayout moreView = new LinearLayout(mContext);

moreView.setLayoutParams(new LinearLayout.LayoutParams(

LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));

// 將根佈局加到該LinearLayout中

addView(moreView);

// 根佈局裏面的相對佈局

mContentView = new RelativeLayout(mContext);

LinearLayout.LayoutParams linearLp1 = new LinearLayout.LayoutParams(

LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

mContentView.setPadding(10, 10, 10, 10);

// 將相對佈局relayout加到moreView根佈局中

moreView.addView(mContentView, linearLp1);

// 進度條mProgressBar

mProgressBar = new ProgressBar(mContext);

RelativeLayout.LayoutParams relativeLp1 = new RelativeLayout.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

relativeLp1.addRule(RelativeLayout.CENTER_IN_PARENT);

mProgressBar.setVisibility(View.INVISIBLE);

// 將mProgressBar加入相對佈局relayout中

mContentView.addView(mProgressBar, relativeLp1);

// 查看更多的TextView

mHintView = new TextView(mContext);

mHintView.setText("查看更多");

mHintView.setGravity(Gravity.CENTER);

RelativeLayout.LayoutParams relativeLp2 = new RelativeLayout.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

relativeLp2.addRule(RelativeLayout.CENTER_IN_PARENT);

// 將其加入相對佈局relayout中

mContentView.addView(mHintView, relativeLp2);

}

}

XListViewHeader：

package com.home.view;

import java.io.IOException;

import java.io.InputStream;

import android.content.Context;

import android.content.res.AssetManager;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.util.AttributeSet;

import android.view.Gravity;

import android.view.View;

import android.view.ViewGroup;

import android.view.animation.Animation;

import android.view.animation.RotateAnimation;

import android.widget.ImageView;

import android.widget.LinearLayout;

import android.widget.ProgressBar;

import android.widget.RelativeLayout;

import android.widget.TextView;

public class XListViewHeader extends LinearLayout {

private LinearLayout mContainer;

private ImageView mArrowImageView;

private ProgressBar mProgressBar;

private TextView mHintTextView;

private int mState = STATE_NORMAL;

private Animation mRotateUpAnim;

private Animation mRotateDownAnim;

private final int ROTATE_ANIM_DURATION = 180;

public final static int STATE_NORMAL = 0;

public final static int STATE_READY = 1;

public final static int STATE_REFRESHING = 2;

public static final int LINEAROUT_1_ID = 1;

public static final int RELAYOUT_ID = 2;

public static final int HEAD_TIME_VIEW_ID = 3;

public XListViewHeader(Context context) {

super(context);

initView(context);

}

/**

* @param context

* @param attrs

*/

public XListViewHeader(Context context, AttributeSet attrs) {

super(context, attrs);

initView(context);

}

private void initView(Context context) {

// 根佈局

mContainer = new LinearLayout(context);

mContainer.setGravity(Gravity.BOTTOM);

// 初始狀況，設置下拉刷新view高度爲0

LinearLayout.LayoutParams linearLp1 = new LinearLayout.LayoutParams(

LayoutParams.MATCH_PARENT, 0);

// 將根佈局加入該LinearLayout中

addView(mContainer, linearLp1);

setGravity(Gravity.BOTTOM);

// 裏面的相對佈局

RelativeLayout relayout = new RelativeLayout(context);

relayout.setId(RELAYOUT_ID);

LinearLayout.LayoutParams linearLp2 = new LinearLayout.LayoutParams(

LayoutParams.MATCH_PARENT, 60);

// 將裏面的相對佈局加入根佈局中

mContainer.addView(relayout, linearLp2);

// 相對佈局裏的子線性佈局1

LinearLayout linear1 = new LinearLayout(context);

linear1.setId(LINEAROUT_1_ID);

RelativeLayout.LayoutParams relativeLp1 = new RelativeLayout.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

relativeLp1.addRule(RelativeLayout.CENTER_IN_PARENT);

linear1.setGravity(Gravity.CENTER);

linear1.setOrientation(LinearLayout.VERTICAL);

// 將子佈局linear1加入relayout中

relayout.addView(linear1, relativeLp1);

// 下拉刷新提示TextView

mHintTextView = new TextView(context);

mHintTextView.setText("下拉刷新");

LinearLayout.LayoutParams linearLp3 = new LinearLayout.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

// 將TextView加入linear1中

linear1.addView(mHintTextView, linearLp3);

// 子線性佈局1（linear1）裏的線性佈局linear12

LinearLayout linear12 = new LinearLayout(context);

LinearLayout.LayoutParams linearLp4 = new LinearLayout.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

linearLp4.setMargins(0, 3, 0, 0);

// 將linear12加入linear1中

linear1.addView(linear12, linearLp4);

// 提示時間TextView

TextView tv = new TextView(context);

tv.setText("上次更新時間：");

tv.setTextSize(12);

// 將提示時間TextView加入linear12

linear12.addView(tv, linearLp3);

// 時間值TextView

TextView tv2 = new TextView(context);

tv2.setId(HEAD_TIME_VIEW_ID);

tv2.setTextSize(12);

// 將時間值TextView加入linear12

linear12.addView(tv2, linearLp3);

// ImageView

mArrowImageView = new ImageView(context);

RelativeLayout.LayoutParams relativeLp2 = new RelativeLayout.LayoutParams(

ViewGroup.LayoutParams.WRAP_CONTENT,

ViewGroup.LayoutParams.WRAP_CONTENT);

relativeLp2.rightMargin = 20;

relativeLp2.addRule(RelativeLayout.CENTER_VERTICAL);

relativeLp2.addRule(RelativeLayout.LEFT_OF, LINEAROUT_1_ID);

mArrowImageView.setImageBitmap(readAssetImage(context));

// 將ImageView加到相對佈局relayout中

relayout.addView(mArrowImageView, relativeLp2);

// ProgressBar

mProgressBar = new ProgressBar(context);

RelativeLayout.LayoutParams relativeLp3 = new RelativeLayout.LayoutParams(

45, 45);

relativeLp3.addRule(RelativeLayout.LEFT_OF, LINEAROUT_1_ID);

relativeLp3.addRule(RelativeLayout.CENTER_VERTICAL);

relativeLp3.rightMargin = 20;

mProgressBar.setVisibility(View.INVISIBLE);

// 將mProgressBar加到相對佈局relayout中

relayout.addView(mProgressBar, relativeLp3);

mRotateUpAnim = new RotateAnimation(0.0f, -180.0f,

Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,

0.5f);

mRotateUpAnim.setDuration(ROTATE_ANIM_DURATION);

mRotateUpAnim.setFillAfter(true);

mRotateDownAnim = new RotateAnimation(-180.0f, 0.0f,

Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,

0.5f);

mRotateDownAnim.setDuration(ROTATE_ANIM_DURATION);

mRotateDownAnim.setFillAfter(true);

}

public void setState(int state) {

if (state == mState)

return;

if (state == STATE_REFRESHING) { // 顯示進度

mArrowImageView.clearAnimation();

mArrowImageView.setVisibility(View.INVISIBLE);

mProgressBar.setVisibility(View.VISIBLE);

} else { // 顯示箭頭圖片

mArrowImageView.setVisibility(View.VISIBLE);

mProgressBar.setVisibility(View.INVISIBLE);

}

switch (state) {

case STATE_NORMAL:

if (mState == STATE_READY) {

mArrowImageView.startAnimation(mRotateDownAnim);

}

if (mState == STATE_REFRESHING) {

mArrowImageView.clearAnimation();

}

mHintTextView.setText("下拉刷新");

break;

case STATE_READY:

if (mState != STATE_READY) {

mArrowImageView.clearAnimation();

mArrowImageView.startAnimation(mRotateUpAnim);

mHintTextView.setText("鬆開刷新數據");

}

break;

case STATE_REFRESHING:

mHintTextView.setText("正在加載...");

break;

default:

}

mState = state;

}

public void setVisiableHeight(int height) {

if (height < 0)

height = 0;

LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContainer

.getLayoutParams();

lp.height = height;

mContainer.setLayoutParams(lp);

}

public int getVisiableHeight() {

return mContainer.getHeight();

}

/**

* 讀取assets裏面文件名爲xlistview_arrow.png的圖片

*

* @param context

* @return bitmap

*/

private Bitmap readAssetImage(Context context) {

AssetManager asset = context.getAssets();

InputStream assetFile = null;

Bitmap bitmap = null;

try {

assetFile = asset.open("xlistview_arrow.png");

bitmap = BitmapFactory.decodeStream(assetFile);

} catch (IOException e) {

e.printStackTrace();

}

return bitmap;

}

}

而後將使用到的那張圖片放在assets目錄下和src一塊兒打包便可。

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