标签:ges ever upd bsp tar end maxheight duration source
根据listview的手指移动事件,动态设置listview上面的图片的宽高,并在手指放开的时候
实现图片的动画(随时间变化的动画值) ValueAnimator.ofInt ( )
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Bitmap;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ViewGroup;
import android.view.animation.OvershootInterpolator;
import android.widget.ImageView;
import android.widget.ListView;
/**
* Created by lxj on 2017/1/5.
*/
public class ParallaxListView extends ListView {
public ParallaxListView(Context context) {
super(context);
}
public ParallaxListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ParallaxListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
int originalHeight;//最初的高度,就是120dp
ImageView image;
int maxHeight;//小孩的最大高度,就是设定为图片本身的高度
public void setParallaxImage(ImageView image){
this.image = image;
//从dimens文件中读取image_height的值,并自动转为像素
originalHeight = getResources().getDimensionPixelSize(R.dimen.image_height);
maxHeight = this.image.getDrawable().getIntrinsicHeight();
}
/**
* 该方法是在listview滑动到头的时候执行,并且可以在该方法中获取到手指移动的距离
* @param deltaY 手指移动的距离,顶部到头是负值,底部到头是正值
* @param scrollY scrollTo滚动的坐标
* @param maxOverScrollY listview滑到头之后可以继续滑动的最大距离
* @param isTouchEvent 是否是手指拖动到头,true:是, false:表示是靠惯性滑动到头
* @return
*/
@Override
protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY,
int scrollRangeX, int scrollRangeY,
int maxOverScrollX, int maxOverScrollY,
boolean isTouchEvent) {
//如果是手指拖动到头,并且是顶部到头,其他忽略不处理
if(isTouchEvent && deltaY<0){
//让ImageView的高度随着手指移动而增高
int newHeight = image.getHeight() + Math.abs(deltaY)/3;
//限制newHeight
if(newHeight>maxHeight){
newHeight = maxHeight;
}
ViewGroup.LayoutParams params = image.getLayoutParams();
params.height = newHeight;
image.setLayoutParams(params);
}
return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX,
scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if(ev.getAction()==MotionEvent.ACTION_UP){
//让ImageView的高度缓慢恢复到最初的120高度
ValueAnimator animator = ValueAnimator.ofInt(image.getHeight(),originalHeight);
//监听动画值的变化,实现自己的动画逻辑
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
int value = (int) animation.getAnimatedValue();
//我们需要将value设置给高度
ViewGroup.LayoutParams params = image.getLayoutParams();
params.height = value;
image.setLayoutParams(params);
}
});
animator.setInterpolator(new OvershootInterpolator());
animator.setDuration(500);
animator.start();
}
return super.onTouchEvent(ev);
}
}
import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.AbsListView; import android.widget.ArrayAdapter; import android.widget.ImageView; public class MainActivity extends AppCompatActivity { private ParallaxListView listview; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listview = (ParallaxListView) findViewById(R.id.listview); //去掉listview滑动到头的时候边缘的蓝色阴影 listview.setOverScrollMode(AbsListView.OVER_SCROLL_NEVER); //添加header View header = View.inflate(this, R.layout.header, null); ImageView image = (ImageView) header.findViewById(R.id.image); listview.addHeaderView(header); //设置ImageView listview.setParallaxImage(image); listview.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, Constant.NAMES)); } }
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.zh.parallax97.MainActivity"> <com.itheima.parallax97.ParallaxListView android:id="@+id/listview" android:layout_width="match_parent" android:layout_height="match_parent"/> </RelativeLayout>
仿QQ空间视差效果,ListView.setHeader( )
标签:ges ever upd bsp tar end maxheight duration source
原文地址:http://www.cnblogs.com/Oldz/p/6285974.html