仿IOS效果 带弹簧动画的ListView
最近项目打算做一个界面,类似于dayone首页的界面效果,dayone 是一款付费应用,目前只有IOS端。作为一个资深懒惰的程序员,奉行的宗旨是绝对不重复造一个轮子。于是乎,去网上找一大堆开源项目,发现没有找到合适的,然后,只能硬着头皮自己来了。先看看效果:
效果图
其实写起来也比较简单,就是控制ListView的头部和底部的高度就可以了, 如果用RecycleView实现起来也是一样,只是RecycleView添加头和尾巴稍微麻烦一点,处理点击事件也不是很方便,所以就基于ListView去实现了。实现的代码, 我已经上传到github上了。
1、使用方法
compile 'com.a520wcf.yllistview:YLListView:1.0.1
2、使用介绍:
1)、布局:
布局注意一个小细节android:layout_height 最好是match_parent, 否则ListView每次滑动的时候都有可能需要重新计算条目高度,比较耗费CPU;
<com.a520wcf.yllistview.YLListView android:divider="@android:color/transparent" android:id="@+id/listView" android:layout_width="match_parent" android:layout_height="match_parent" />
2)、代码:
private YLListView listView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listView = (YLListView) findViewById(R.id.listView); // 不添加也有默认的头和底 View topView=View.inflate(this,R.layout.top,null); listView.addHeaderView(topView); View bottomView=new View(getApplicationContext()); listView.addFooterView(bottomView); // 顶部和底部也可以固定最终的高度 不固定就使用布局本身的高度 listView.setFinalBottomHeight(100); listView.setFinalTopHeight(100); listView.setAdapter(new DemoAdapter()); //YLListView默认有头和底 处理点击事件位置注意减去 listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { position=position-listView.getHeaderViewsCount(); } }); }
3、源码介绍
其实这个项目里面只有一个类,大家不需要依赖,直接把这个类复制到项目中就可以了,来看看源码:
package com.a520wcf.yllistview; 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.ListView; import android.widget.Scroller; public class YLListView extends ListView implements AbsListView.OnScrollListener { private Scroller mScroller; // used for scroll back private float mLastY = -1; 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 float OFFSET_RADIO = 1.8f; // total list items, used to detect is at the bottom of ListView. private int mTotalItemCount; private View mHeaderView; // 顶部图片 private View mFooterView; // 底部图片 private int finalTopHeight; private int finalBottomHeight; public YLListView(Context context) { super(context); initWithContext(context); } public YLListView(Context context, AttributeSet attrs) { super(context, attrs); initWithContext(context); } public YLListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initWithContext(context); } private void initWithContext(Context context) { mScroller = new Scroller(context, new DecelerateInterpolator()); super.setOnScrollListener(this); this.getViewTreeObserver().addOnGlobalLayoutListener( new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { if(mHeaderView==null){ View view=new View(getContext()); addHeaderView(view); } if(mFooterView==null){ View view=new View(getContext()); addFooterView(view); } getViewTreeObserver() .removeGlobalOnLayoutListener(this); } }); } @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(); if (getFirstVisiblePosition() == 0 && (mHeaderView.getHeight() > finalTopHeight || deltaY > 0) && mHeaderView.getTop() >= 0) { // the first item is showing, header has shown or pull down. updateHeaderHeight(deltaY / OFFSET_RADIO); } else if (getLastVisiblePosition() == mTotalItemCount - 1 && (getFootHeight() >finalBottomHeight || deltaY < 0)) { updateFooterHeight(-deltaY / OFFSET_RADIO); } break; default: mLastY = -1; // reset if (getFirstVisiblePosition() == 0 && getHeaderHeight() > finalTopHeight) { resetHeaderHeight(); } if (getLastVisiblePosition() == mTotalItemCount - 1 ){ if(getFootHeight() > finalBottomHeight) { resetFooterHeight(); } } break; } return super.onTouchEvent(ev); } /** * 重置底部高度 */ private void resetFooterHeight() { int bottomHeight = getFootHeight(); if (bottomHeight > finalBottomHeight) { mScrollBack = SCROLLBACK_FOOTER; mScroller.startScroll(0, bottomHeight, 0, -bottomHeight+finalBottomHeight, SCROLL_DURATION); invalidate(); } } // 计算滑动 当invalidate()后 系统会自动调用 @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { if (mScrollBack == SCROLLBACK_HEADER) { setHeaderHeight(mScroller.getCurrY()); } else { setFooterViewHeight(mScroller.getCurrY()); } postInvalidate(); } super.computeScroll(); } // 设置顶部高度 private void setHeaderHeight(int height) { LayoutParams layoutParams = (LayoutParams) mHeaderView.getLayoutParams(); layoutParams.height = height; mHeaderView.setLayoutParams(layoutParams); } // 设置底部高度 private void setFooterViewHeight(int height) { LayoutParams layoutParams = (LayoutParams) mFooterView.getLayoutParams(); layoutParams.height =height; mFooterView.setLayoutParams(layoutParams); } // 获取顶部高度 public int getHeaderHeight() { AbsListView.LayoutParams layoutParams = (AbsListView.LayoutParams) mHeaderView.getLayoutParams(); return layoutParams.height; } // 获取底部高度 public int getFootHeight() { AbsListView.LayoutParams layoutParams = (AbsListView.LayoutParams) mFooterView.getLayoutParams(); return layoutParams.height; } private void resetHeaderHeight() { int height = getHeaderHeight(); if (height == 0) // not visible. return; mScrollBack = SCROLLBACK_HEADER; mScroller.startScroll(0, height, 0, finalTopHeight - height, SCROLL_DURATION); invalidate(); } /** * 设置顶部高度 如果不设置高度,默认就是布局本身的高度 * @param height 顶部高度 */ public void setFinalTopHeight(int height) { this.finalTopHeight = height; } /** * 设置底部高度 如果不设置高度,默认就是布局本身的高度 * @param height 底部高度 */ public void setFinalBottomHeight(int height){ this.finalBottomHeight=height; } @Override public void addHeaderView(View v) { mHeaderView = v; super.addHeaderView(mHeaderView); mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener( new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { if(finalTopHeight==0) { finalTopHeight = mHeaderView.getMeasuredHeight(); } setHeaderHeight(finalTopHeight); getViewTreeObserver() .removeGlobalOnLayoutListener(this); } }); } @Override public void addFooterView(View v) { mFooterView = v; super.addFooterView(mFooterView); mFooterView.getViewTreeObserver().addOnGlobalLayoutListener( new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { if(finalBottomHeight==0) { finalBottomHeight = mFooterView.getMeasuredHeight(); } setFooterViewHeight(finalBottomHeight); getViewTreeObserver() .removeGlobalOnLayoutListener(this); } }); } private OnScrollListener mScrollListener; // user's scroll listener @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); } } private void updateHeaderHeight(float delta) { setHeaderHeight((int) (getHeaderHeight()+delta)); setSelection(0); // scroll to top each time } private void updateFooterHeight(float delta) { setFooterViewHeight((int) (getFootHeight()+delta)); } }
以上就是本文的全部内容,希望对大家的学习有所帮助。
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