Android PullToZoomListView实现放大回弹效果

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mb5fe94b3e552d9 2017-04-12 18:42:00

文章标签 android 控件 ide github 开源项目 文章分类 代码人生

版本号：1.0

日期：2014.8.4

之前看过一篇文章，链接是：能够下拉缩放HeaderView的ListView:PullToZoomInListView。

说的就是PullToZoomListView。只是这篇文章有个地方须要勘误，就是PullToZoomListView这个控件尽管是github上一个开源项目。只是最美应用并非使用这个开源项目，而是这个开源项目反编译了最美应用的代码。

可是，它这个代码是有问题的，当手指在屏幕上滑动的时候会引发onItemClick事件。

看了一下它的代码。发现是由于在onTouchEvent()方法中的MotionEvent.ACTION_MOVE中return true了，这样就会消费这个事件。所以导致了onItemClick事件。

之后我也反编译了一下最美应用，看了一下这个控件的实现，发现还有其它问题，比方少了一些变量，没有重写onInterceptTouchEvent()方法等。因此我又自己动手把这个控件丰富了一下。使其能够最大限度的接近原始代码。并且可正常使用。改动后代码例如以下：

package com.kince.android.pulltozoomlistview;

import android.app.Activity;
import android.content.Context;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
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 boolean mScrollable = true;
  private boolean mShowHeaderImage = true;
  private boolean mZoomable = true;

  public PullToZoomListView(Context paramContext) {
    super(paramContext);
    init(paramContext);
  }

  public PullToZoomListView(Context paramContext,
      AttributeSet paramAttributeSet) {
    super(paramContext, paramAttributeSet);
    init(paramContext);
  }

  public PullToZoomListView(Context paramContext,
      AttributeSet paramAttributeSet, int paramInt) {
    super(paramContext, paramAttributeSet, paramInt);
    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) (9.0F * (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;
    Log.d("onSecondaryPointerUp", i + "");
    if (paramMotionEvent.getPointerId(i) == this.mActivePointerId)
      if (i != 0) {
        this.mLastMotionY = paramMotionEvent.getY(1);
        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 void hideHeaderImage() {
    this.mShowHeaderImage = false;
    this.mZoomable = false;
    this.mScrollable = false;
    removeHeaderView(this.mHeaderContainer);
  }

  public boolean isScrollable() {
    return this.mScrollable;
  }

  public boolean isZoomable() {
    return this.mZoomable;
  }

  public boolean onInterceptTouchEvent(MotionEvent paramMotionEvent) {
    if (!this.mZoomable) {
      return super.onInterceptTouchEvent(paramMotionEvent);
    }
    switch (paramMotionEvent.getAction() & MotionEvent.ACTION_MASK) {
    case MotionEvent.ACTION_DOWN:

      this.mActivePointerId = paramMotionEvent.getPointerId(0);
      this.mMaxScale = (this.mScreenHeight / this.mHeaderHeight);
      break;

    case MotionEvent.ACTION_UP:
      reset();
      break;

    case MotionEvent.ACTION_POINTER_DOWN:
      this.mActivePointerId = paramMotionEvent
          .getPointerId(paramMotionEvent.getActionIndex());
      break;

    case MotionEvent.ACTION_POINTER_UP:
      onSecondaryPointerUp(paramMotionEvent);
      break;
    }
    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();
  }

  @Override
  public void onScroll(AbsListView paramAbsListView, int paramInt1,
      int paramInt2, int paramInt3) {
    if (this.mScrollable) {
      Log.d(TAG, "onScroll");
      float f = this.mHeaderHeight - this.mHeaderContainer.getBottom();
      Log.d("onScroll", "f|" + f);
      if ((f > 0.0F) && (f < this.mHeaderHeight)) {
        Log.d("onScroll", "1");
        int i = (int) (0.65D * f);
        this.mHeaderImage.scrollTo(0, -i);
      } else if (this.mHeaderImage.getScrollY() != 0) {
        Log.d("onScroll", "2");
        this.mHeaderImage.scrollTo(0, 0);
      }
    }

    if (this.mOnScrollListener != null) {
      this.mOnScrollListener.onScroll(paramAbsListView, paramInt1,
          paramInt2, paramInt3);
    }
  }

  public void onScrollStateChanged(AbsListView paramAbsListView, int paramInt) {
    if (this.mOnScrollListener != null)
      this.mOnScrollListener.onScrollStateChanged(paramAbsListView,
          paramInt);
  }

  public boolean onTouchEvent(MotionEvent ev) {

    Log.d(TAG, "" + (0xFF & ev.getAction()));
    if (!this.mZoomable) {
      Log.i("zoom", "zoom");
      return super.onTouchEvent(ev);
    }
    switch (ev.getAction() & MotionEvent.ACTION_MASK) {
    case MotionEvent.ACTION_OUTSIDE:
    case MotionEvent.ACTION_DOWN:
      if (!this.mScalingRunnalable.mIsFinished) {
        this.mScalingRunnalable.abortAnimation();
      }
      this.mLastMotionY = ev.getY();
      this.mActivePointerId = ev.getPointerId(0);
      this.mMaxScale = (this.mScreenHeight / this.mHeaderHeight);
      this.mLastScale = (this.mHeaderContainer.getBottom() / this.mHeaderHeight);
      break;
    case MotionEvent.ACTION_MOVE:
      Log.d("onTouchEvent", "mActivePointerId" + mActivePointerId);
      int j = ev.findPointerIndex(this.mActivePointerId);
      if (j == -1) {
        Log.e("PullToZoomListView", "Invalid pointerId="
            + this.mActivePointerId + " in onTouchEvent");
      } else {
        if (this.mLastMotionY == -1.0F)
          this.mLastMotionY = ev.getY(j);
        if (this.mHeaderContainer.getBottom() >= this.mHeaderHeight) {
          ViewGroup.LayoutParams localLayoutParams = this.mHeaderContainer
              .getLayoutParams();
          float f = ((ev.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);
          }
          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 = ev.getY(j);
        }
        this.mLastMotionY = ev.getY(j);
      }
      break;
    case MotionEvent.ACTION_UP:
      reset();
      endScraling();
      break;
    case MotionEvent.ACTION_CANCEL:

      break;
    case MotionEvent.ACTION_POINTER_DOWN:
      int i = ev.getActionIndex();
      this.mLastMotionY = ev.getY(i);
      this.mActivePointerId = ev.getPointerId(i);
      break;
    case MotionEvent.ACTION_POINTER_UP:
      onSecondaryPointerUp(ev);
      this.mLastMotionY = ev.getY(ev
          .findPointerIndex(this.mActivePointerId));
      break;
    }
    return super.onTouchEvent(ev);
  }

  public void setHeaderViewSize(int paramInt1, int paramInt2) {
    if (!this.mShowHeaderImage) {
      return;
    }
    Object localObject = this.mHeaderContainer.getLayoutParams();
    if (localObject == null)
      localObject = new AbsListView.LayoutParams(paramInt1, paramInt2);
    ((ViewGroup.LayoutParams) localObject).width = paramInt1;
    ((ViewGroup.LayoutParams) localObject).height = paramInt2;
    this.mHeaderContainer
        .setLayoutParams((ViewGroup.LayoutParams) localObject);
    this.mHeaderHeight = paramInt2;
  }

  public void setOnScrollListener(
      AbsListView.OnScrollListener paramOnScrollListener) {
    this.mOnScrollListener = paramOnScrollListener;
  }

  public void setScrollable(boolean paramBoolean) {
    if (!this.mShowHeaderImage) {
      return;
    }
    this.mScrollable = paramBoolean;
  }

  public void setShadow(int paramInt) {
    if (!this.mShowHeaderImage) {
      return;
    }
    this.mShadow.setBackgroundResource(paramInt);
  }

  public void setZoomable(boolean paramBoolean) {
    if (!this.mShowHeaderImage) {
      return;
    }
    this.mZoomable = paramBoolean;
  }

  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);
    }
  }
}