ListView 滑动HeadImage的动态缩放

源码：http://pan.baidu.com/s/1eRp8UEQ

自定ListView 实现OnScrollListener 接口

package com.example.pullzoomview;import android.app.Activity;import android.content.Context;import android.graphics.Color;import android.os.SystemClock;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.view.animation.Interpolator;import android.widget.AbsListView;import android.widget.FrameLayout;import android.widget.ImageView;import android.widget.ListView;public class PullToZoomListView extends ListView implements AbsListView.OnScrollListener {    private static final int INVALID_VALUE = -1;    private static final String TAG = "PullToZoomListView";    private static final Interpolator sInterpolator = new Interpolator() {        public float getInterpolation(float paramAnonymousFloat) {            float f = paramAnonymousFloat - 1.0F;            return 1.0F + f * (f * (f * (f * f)));        }    };    int mActivePointerId = -1;    private FrameLayout mHeaderContainer;    private int mHeaderHeight;    private ImageView mHeaderImage;    float mLastMotionY = -1.0F;    float mLastScale = -1.0F;    float mMaxScale = -1.0F;    private AbsListView.OnScrollListener mOnScrollListener;    private ScalingRunnalable mScalingRunnalable;    private int mScreenHeight;    private ImageView mShadow;    private View titleView;    public void setTitleView(View titleView) {        this.titleView = titleView;    }    public PullToZoomListView(Context paramContext) {        super(paramContext);        System.out.println("----1");        init(paramContext);    }    public PullToZoomListView(Context paramContext, AttributeSet paramAttributeSet) {        super(paramContext, paramAttributeSet);        System.out.println("----2");        init(paramContext);    }    public PullToZoomListView(Context paramContext, AttributeSet paramAttributeSet, int paramInt) {        super(paramContext, paramAttributeSet, paramInt);        System.out.println("----3");        init(paramContext);    }    private void endScraling() {        if (this.mHeaderContainer.getBottom() >= this.mHeaderHeight)            Log.d("mmm", "endScraling");        this.mScalingRunnalable.startAnimation(200L);    }    private void init(Context paramContext) {        DisplayMetrics localDisplayMetrics = new DisplayMetrics();        ((Activity) paramContext).getWindowManager().getDefaultDisplay().getMetrics(localDisplayMetrics);        this.mScreenHeight = localDisplayMetrics.heightPixels;        this.mHeaderContainer = new FrameLayout(paramContext);        this.mHeaderImage = new ImageView(paramContext);        int i = localDisplayMetrics.widthPixels;        setHeaderViewSize(i, (int) (12.0F * (i / 16.0F)));        this.mShadow = new ImageView(paramContext);        FrameLayout.LayoutParams localLayoutParams = new FrameLayout.LayoutParams(-1, -2);        localLayoutParams.gravity = 80;        this.mShadow.setLayoutParams(localLayoutParams);        this.mHeaderContainer.addView(this.mHeaderImage);        this.mHeaderContainer.addView(this.mShadow);        addHeaderView(this.mHeaderContainer);        this.mScalingRunnalable = new ScalingRunnalable();        super.setOnScrollListener(this);    }    private void onSecondaryPointerUp(MotionEvent paramMotionEvent) {        int i = (paramMotionEvent.getAction()) >> 8;        if (paramMotionEvent.getPointerId(i) == this.mActivePointerId)            if (i != 0) {                int j = 1;                this.mLastMotionY = paramMotionEvent.getY(0);                this.mActivePointerId = paramMotionEvent.getPointerId(0);                return;            }    }    private void reset() {        this.mActivePointerId = -1;        this.mLastMotionY = -1.0F;        this.mMaxScale = -1.0F;        this.mLastScale = -1.0F;    }    public ImageView getHeaderView() {        return this.mHeaderImage;    }    public boolean onInterceptTouchEvent(MotionEvent paramMotionEvent) {        return super.onInterceptTouchEvent(paramMotionEvent);    }    protected void onLayout(boolean paramBoolean, int paramInt1, int paramInt2, int paramInt3, int paramInt4) {        super.onLayout(paramBoolean, paramInt1, paramInt2, paramInt3, paramInt4);        if (this.mHeaderHeight == 0)            this.mHeaderHeight = this.mHeaderContainer.getHeight();    }    private Integer titleColor;    @Override    public void onScroll(AbsListView paramAbsListView, int paramInt1, int paramInt2, int paramInt3) {        // Log.d("mmm", "onScroll");        float f = this.mHeaderHeight - this.mHeaderContainer.getBottom();        // Log.d("mmm", "f|" + f);        if ((f > 0.0F) && (f < this.mHeaderHeight)) {            // Log.d("mmm", "1");            int i = (int) (0.65D * f);            this.mHeaderImage.scrollTo(0, -i);        } else if (this.mHeaderImage.getScrollY() != 0) {            // Log.d("mmm", "2");            this.mHeaderImage.scrollTo(0, 0);        }        if (this.mOnScrollListener != null) {            this.mOnScrollListener.onScroll(paramAbsListView, paramInt1, paramInt2, paramInt3);        }        View c = paramAbsListView.getChildAt(0);        if (c == null) {            return;        }        // assuming all list items have same height        int scrolly = -c.getTop() + paramAbsListView.getPaddingTop()                + paramAbsListView.getFirstVisiblePosition() * c.getHeight();        // some code        if (titleColor == null) {            titleColor = getResources().getColor(R.color.title);        }        int height = c.getHeight() - titleView.getHeight();        if (titleView != null)            if (scrolly <= height) {                float scale = (float) scrolly / height;                float alpha = (255 * scale);                // Log.i("TAG","alpha--->"+alpha);                // 只是layout背景透明                titleView.setBackgroundColor(Color.argb((int) alpha, Color.red(titleColor), Color.green(titleColor),                        Color.blue(titleColor)));            }    }    public void onScrollStateChanged(AbsListView paramAbsListView, int paramInt) {        if (this.mOnScrollListener != null)            this.mOnScrollListener.onScrollStateChanged(paramAbsListView, paramInt);    }    public boolean onTouchEvent(MotionEvent paramMotionEvent) {        Log.d("mmm", "" + (0xFF & paramMotionEvent.getAction()));        switch (0xFF & paramMotionEvent.getAction()) {        case 4:        case 0:            if (!this.mScalingRunnalable.mIsFinished) {                this.mScalingRunnalable.abortAnimation();            }            this.mLastMotionY = paramMotionEvent.getY();            this.mActivePointerId = paramMotionEvent.getPointerId(0);            this.mMaxScale = (this.mScreenHeight / this.mHeaderHeight);            this.mLastScale = (this.mHeaderContainer.getBottom() / this.mHeaderHeight);            break;        case 2:            Log.d("mmm", "mActivePointerId" + mActivePointerId);            int j = paramMotionEvent.findPointerIndex(this.mActivePointerId);            if (j == -1) {                Log.e("PullToZoomListView", "Invalid pointerId=" + this.mActivePointerId + " in onTouchEvent");            } else {                if (this.mLastMotionY == -1.0F)                    this.mLastMotionY = paramMotionEvent.getY(j);                if (this.mHeaderContainer.getBottom() >= this.mHeaderHeight) {                    ViewGroup.LayoutParams localLayoutParams = this.mHeaderContainer.getLayoutParams();                    float f = ((paramMotionEvent.getY(j) - this.mLastMotionY + this.mHeaderContainer.getBottom())                            / this.mHeaderHeight - this.mLastScale) / 2.0F + this.mLastScale;                    if ((this.mLastScale <= 1.0D) && (f < this.mLastScale)) {                        localLayoutParams.height = this.mHeaderHeight;                        this.mHeaderContainer.setLayoutParams(localLayoutParams);                        return super.onTouchEvent(paramMotionEvent);                    }                    this.mLastScale = Math.min(Math.max(f, 1.0F), this.mMaxScale);                    localLayoutParams.height = ((int) (this.mHeaderHeight * this.mLastScale));                    if (localLayoutParams.height < this.mScreenHeight)                        this.mHeaderContainer.setLayoutParams(localLayoutParams);                    this.mLastMotionY = paramMotionEvent.getY(j);                    return true;                }                this.mLastMotionY = paramMotionEvent.getY(j);            }            break;        case 1:            reset();            endScraling();            break;        case 3:            int i = paramMotionEvent.getActionIndex();            this.mLastMotionY = paramMotionEvent.getY(i);            this.mActivePointerId = paramMotionEvent.getPointerId(i);            break;        case 5:            onSecondaryPointerUp(paramMotionEvent);            this.mLastMotionY = paramMotionEvent.getY(paramMotionEvent.findPointerIndex(this.mActivePointerId));            break;        case 6:        }        return super.onTouchEvent(paramMotionEvent);    }    public void setHeaderViewSize(int width, int heiht) {        Object localObject = this.mHeaderContainer.getLayoutParams();        if (localObject == null)            localObject = new AbsListView.LayoutParams(width, heiht);        ((ViewGroup.LayoutParams) localObject).width = width;        ((ViewGroup.LayoutParams) localObject).height = heiht;        this.mHeaderContainer.setLayoutParams((ViewGroup.LayoutParams) localObject);        this.mHeaderHeight = heiht;    }    public void setOnScrollListener(AbsListView.OnScrollListener paramOnScrollListener) {        this.mOnScrollListener = paramOnScrollListener;    }    public void setShadow(int paramInt) {        this.mShadow.setBackgroundResource(paramInt);    }    class ScalingRunnalable implements Runnable {        long mDuration;        boolean mIsFinished = true;        float mScale;        long mStartTime;        ScalingRunnalable() {        }        public void abortAnimation() {            this.mIsFinished = true;        }        public boolean isFinished() {            return this.mIsFinished;        }        public void run() {            float f2;            ViewGroup.LayoutParams localLayoutParams;            if ((!this.mIsFinished) && (this.mScale > 1.0D)) {                float f1 = ((float) SystemClock.currentThreadTimeMillis() - (float) this.mStartTime)                        / (float) this.mDuration;                f2 = this.mScale - (this.mScale - 1.0F) * PullToZoomListView.sInterpolator.getInterpolation(f1);                localLayoutParams = PullToZoomListView.this.mHeaderContainer.getLayoutParams();                if (f2 > 1.0F) {                    Log.d("mmm", "f2>1.0");                    localLayoutParams.height = PullToZoomListView.this.mHeaderHeight;                    ;                    localLayoutParams.height = ((int) (f2 * PullToZoomListView.this.mHeaderHeight));                    PullToZoomListView.this.mHeaderContainer.setLayoutParams(localLayoutParams);                    PullToZoomListView.this.post(this);                    return;                }                this.mIsFinished = true;            }        }        public void startAnimation(long paramLong) {            this.mStartTime = SystemClock.currentThreadTimeMillis();            this.mDuration = paramLong;            this.mScale = ((float) (PullToZoomListView.this.mHeaderContainer.getBottom())                    / PullToZoomListView.this.mHeaderHeight);            this.mIsFinished = false;            PullToZoomListView.this.post(this);        }    }}

headLayout 布局文件 /res/layout/layout_head.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/view_head"    android:layout_width="fill_parent"    android:layout_height="50dp"    android:background="@color/title" >    <TextView        android:id="@+id/tvHead"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_marginLeft="65dp"        android:layout_marginRight="65dp"        android:gravity="center"        android:singleLine="true"        android:text="android"        android:textColor="#fff"        android:textSize="16sp" />    <ImageView        android:id="@+id/ibBack"        android:layout_width="40dp"        android:layout_height="40dp"        android:layout_centerVertical="true"        android:clickable="true"        android:padding="8dp"        android:scaleType="fitXY" />    <TextView        android:id="@+id/head_rightTv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_centerVertical="true"        android:paddingLeft="15dp"        android:paddingRight="20dp"        android:text="1234"        android:textColor="#fff"        android:textSize="18sp"        android:visibility="gone" />    <ImageView        android:id="@+id/head_rightIv"        android:layout_width="40dp"        android:layout_height="40dp"        android:layout_alignParentRight="true"        android:layout_centerVertical="true"        android:clickable="true"        android:padding="10dp"        android:scaleType="fitXY"        android:visibility="gone" /></RelativeLayout>

主页面布局 /res/layout/main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#eee"    android:paddingBottom="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <com.example.pullzoomview.PullToZoomListView        android:id="@+id/listview"        android:layout_width="fill_parent"        android:layout_height="fill_parent" >    </com.example.pullzoomview.PullToZoomListView>    <include layout="@layout/layout_head" /></RelativeLayout>

layout_head.xml 布局整体背景颜色 /res/values/colors.xml

<resources    xmlns:android="http://schemas.android.com/apk/res/android"    >    <color name="title">#efefef</color></resources>