Android如何实现仿QQ可拉伸头部控件

小编给大家分享一下Android如何实现仿QQ可拉伸头部控件，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！

该控件大致思路：

1.采用继承listview加入头部view。 2.监听listview滚动。 3.自定义动画回弹。

activity-main.xml布局如下：

headerview.xml布局：

list_item布局：

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activity代码：

package com.example.headerlistview;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import android.os.Bundle;import android.app.Activity;import android.view.LayoutInflater;import android.view.Menu;import android.view.View;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.ListView;import android.widget.SimpleAdapter;public class MainActivity extends Activity { private HeaderListView header_lv; private ImageView header_iv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); getHeaderView(); initView(); } private void initView() { // TODO Auto-generated method stub header_lv=(HeaderListView) findViewById(R.id.header_lv); header_lv.addHeaderView(getHeaderView()); header_lv.setHeaderView(header_iv); header_lv.setAdapter(getSimpleAdapter()); } public BaseAdapter getSimpleAdapter(){ List> data=new ArrayList>(); for(int i=0;i<15;i++){ Map map=new HashMap(); map.put("name", "郑州___"+i); map.put("describe", "asdfasdfasdfasdfasdfsadfsad"); data.add(map); } SimpleAdapter simpleAdapter=new SimpleAdapter(this, data, R.layout.list_item, new String[]{"name","describe"}, new int[]{R.id.tv_name,R.id.tv_describe}); return simpleAdapter; } public View getHeaderView(){ View view= getLayoutInflater().inflate(R.layout.headerview, null); header_iv =(ImageView) view.findViewById(R.id.header_image); return view; }}

自定义控件HeaderListView:

package com.example.headerlistview;import java.security.spec.ECField;import android.annotation.SuppressLint;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.animation.Animation;import android.view.animation.Transformation;import android.widget.ImageView;import android.widget.ListView;public class HeaderListView extends ListView { private ImageView headerView; private int headerView_initHeight;//imageview初始高度 public void setHeaderView(ImageView headerView) { this.headerView = headerView; } public HeaderListView(Context context) { super(context); // TODO Auto-generated constructor stub } public HeaderListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // TODO Auto-generated constructor stub } public HeaderListView(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub } /** * listview焦点改变时--获取iamgeview高度的初始值，该值不能在构造方法中获取 */ @Override public void onWindowFocusChanged(boolean hasWindowFocus) { // TODO Auto-generated method stub super.onWindowFocusChanged(hasWindowFocus); if(hasWindowFocus){ this.headerView_initHeight=headerView.getHeight(); } } @SuppressLint("NewApi") @Override protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) { // 滑动过头的时候调用 boolean bl=resizeHeaderView(deltaY); return bl?true:super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent); } /** * 控制imageview高度的增加 * @param deltaY 偏移量 */ private boolean resizeHeaderView(int deltaY) { if(Math.abs((double)deltaY)<200){ if(deltaY<0){ headerView.getLayoutParams().height=headerView.getHeight()-deltaY; //重新绘制 headerView.requestLayout(); }else{ headerView.getLayoutParams().height=headerView.getHeight()-deltaY; headerView.requestLayout(); } } return false; } @Override protected void onScrollChanged(int l, int t, int oldl, int oldt) { // TODO Auto-generated method stub super.onScrollChanged(l, t, oldl, oldt); //获取imageview父控件 View parent=(View) headerView.getParent(); //当父控件的top值小于零或者高度大于原始高度时触发 if(parent.getTop()<0||headerView.getHeight()>headerView_initHeight){ headerView.getLayoutParams().height=headerView.getHeight()+parent.getTop(); parent.layout(parent.getLeft(),0, parent.getRight(), parent.getHeight()); headerView.requestLayout(); } } @Override public boolean onTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub if(ev.getAction()==MotionEvent.ACTION_UP||ev.getAction()==MotionEvent.ACTION_CANCEL){ MyAnimation animation=new MyAnimation(headerView, headerView_initHeight); animation.setDuration(200); headerView.startAnimation(animation); } return super.onTouchEvent(ev); } public class MyAnimation extends Animation{ private ImageView header_iv; private int currentHeight; private int targetHeight; private int poorHeight; public MyAnimation(ImageView iv,int targetHeight){ this.header_iv=iv; this.targetHeight=targetHeight; this.currentHeight=iv.getHeight(); this.poorHeight=this.currentHeight-this.targetHeight; } /** * 动画执行期间执行该方法，不断执行 * interpolatedTime：当前时间与duration的时间比（时间执行百分比） */ @Override protected void applyTransformation(float interpolatedTime, Transformation t) { // TODO Auto-generated method stub super.applyTransformation(interpolatedTime, t); this.header_iv.getLayoutParams().height=(int)(currentHeight-poorHeight*interpolatedTime); this.header_iv.requestLayout(); } }}

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