ActivityGroup内のActivity内のviewpagerでviewpagerのPull to Refreshグリッドビューを使用するとClassCastExceptionが発生する

Question

ViewPagerでPullToRefresh GridViewを使用してClassCastExceptionを発生させようとしています。これが例外です。

FATAL EXCEPTION: main java.lang.ClassCastException: android.support.v4.view.ViewPager$LayoutParams 
at android.widget.LinearLayout.measureVertical(LinearLayout.java:360) 
at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) 
at android.view.View.measure(View.java:8313) 
at android.widget.RelativeLayout.measureChild(RelativeLayout.java:566) 
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:381) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:581) 
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:365) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017) 
at android.widget.LinearLayout.measureVertical(LinearLayout.java:386) 
at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
at android.view.View.measure(View.java:8313) 
at android.view.ViewRoot.performTraversals(ViewRoot.java:845) 
at android.view.ViewRoot.handleMessage(ViewRoot.java:1865) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:130) 
at android.app.ActivityThread.main(ActivityThread.java:3687) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:507) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 
at dalvik.system.NativeStart.main(Native Method) 

これは実装されているコードスニペットです。

これはPullToRefreshライブラリのコードスニペットであり、これが原因である可能性があります。

package com.syncusup.pulltorefresh.library.my; 

import android.content.Context; 
import android.os.Handler; 
import android.util.AttributeSet; 
import android.view.LayoutInflater; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.View.OnTouchListener; 
import android.view.ViewGroup; 
import android.view.animation.AccelerateDecelerateInterpolator; 
import android.view.animation.Animation; 
import android.view.animation.Interpolator; 
import android.view.animation.LinearInterpolator; 
import android.view.animation.RotateAnimation; 
import android.widget.AdapterView; 
import android.widget.ImageView; 
import android.widget.LinearLayout; 
import android.widget.ListAdapter; 
import android.widget.ProgressBar; 
import android.widget.TextView; 

import com.syncusup.R; 

public abstract class PullToRefreshBase<T extends AdapterView<ListAdapter>> extends LinearLayout implements 
     OnTouchListener { 

    private final class SmoothScrollRunnable implements Runnable { 

     static final int ANIMATION_DURATION_MS = 190; 
     static final int ANIMATION_FPS = 1000/60; 

     private final Interpolator interpolator; 
     private final int scrollToY; 
     private final int scrollFromY; 
     private final Handler handler; 

     private boolean continueRunning = true; 
     private long startTime = -1; 
     private int currentY = -1; 

     public SmoothScrollRunnable(Handler handler, int fromY, int toY) { 
      this.handler = handler; 
      this.scrollFromY = fromY; 
      this.scrollToY = toY; 
      this.interpolator = new AccelerateDecelerateInterpolator(); 
     } 

     @Override 
     public void run() { 

      /** 
      * Only set startTime if this is the first time we're starting, else 
      * actually calculate the Y delta 
      */ 
      if (startTime == -1) { 
       startTime = System.currentTimeMillis(); 
      } else { 

       /** 
       * We do do all calculations in long to reduce software float 
       * calculations. We use 1000 as it gives us good accuracy and 
       * small rounding errors 
       */ 
       long normalizedTime = (1000 * (System.currentTimeMillis() - startTime))/ANIMATION_DURATION_MS; 
       normalizedTime = Math.max(Math.min(normalizedTime, 1000), 0); 

       final int deltaY = Math.round((scrollFromY - scrollToY) 
         * interpolator.getInterpolation(normalizedTime/1000f)); 
       this.currentY = scrollFromY - deltaY; 
       setHeaderScroll(currentY); 
      } 

      // If we're not at the target Y, keep going... 
      if (continueRunning && scrollToY != currentY) { 
       handler.postDelayed(this, ANIMATION_FPS); 
      } 
     } 

     public void stop() { 
      this.continueRunning = false; 
      this.handler.removeCallbacks(this); 
     } 
    }; 

    // =========================================================== 
    // Constants 
    // =========================================================== 

    static final int PULL_TO_REFRESH = 0; 
    static final int RELEASE_TO_REFRESH = PULL_TO_REFRESH + 1; 
    static final int REFRESHING = RELEASE_TO_REFRESH + 1; 
    static final int EVENT_COUNT = 3; 

    // =========================================================== 
    // Fields 
    // =========================================================== 

    private int state = PULL_TO_REFRESH; 
    private T adapterView; 
    private boolean isPullToRefreshEnabled = true; 

    private ProgressBar headerProgress; 
    private TextView headerText; 
    private ImageView headerImage; 
    private Animation flipAnimation, reverseAnimation; 
    private int headerHeight; 

    private final Handler handler = new Handler(); 

    private OnTouchListener onTouchListener; 
    private OnRefreshListener onRefreshListener; 

    private SmoothScrollRunnable currentSmoothScrollRunnable; 

    private float startY = -1; 
    private final float[] lastYs = new float[EVENT_COUNT]; 

    private String releaseLabel; 
    private String pullLabel; 
    private String refreshingLabel; 

    // =========================================================== 
    // Constructors 
    // =========================================================== 

    public PullToRefreshBase(Context context) { 
     this(context, null); 
    } 

    public PullToRefreshBase(Context context, AttributeSet attrs) { 
     super(context, attrs); 
     init(context, attrs); 
    } 

    // =========================================================== 
    // Getter & Setter 
    // =========================================================== 

    /** 
    * Get the Wrapped AdapterView. Anything returned here has already been 
    * added to the content view. 
    * 
    * @return The AdapterView which is currently wrapped 
    */ 
    public final T getAdapterView() { 
     return adapterView; 
    } 

    /** 
    * Whether Pull-to-Refresh is enabled 
    * 
    * @return enabled 
    */ 
    public boolean isPullToRefreshEnabled() { 
     return isPullToRefreshEnabled; 
    } 

    /** 
    * Mark the current Refresh as complete. Will Reset the UI and hide the 
    * Refreshing View 
    */ 
    public void onRefreshComplete() { 
     resetHeader(); 
    } 

    public void setOnRefreshListener(OnRefreshListener listener) { 
     onRefreshListener = listener; 
    } 

    /** 
    * A mutator to enable/disable Pull-to-Refresh for the current AdapterView 
    * 
    * @param enable 
    *   Whether Pull-To-Refresh should be used 
    */ 
    public void setPullToRefreshEnabled(boolean enabled) { 
     this.isPullToRefreshEnabled = enabled; 
    } 

    public void setReleaseLabel(String releaseLabel) { 
     this.releaseLabel = releaseLabel; 
    } 

    public void setPullLabel(String pullLabel) { 
     this.pullLabel = pullLabel; 
    } 

    public void setRefreshingLabel(String refreshingLabel) { 
     this.refreshingLabel = refreshingLabel; 
    } 

    public void setHeaderProgress(ProgressBar headerProgress) { 
     this.headerProgress = headerProgress; 
    } 

    // =========================================================== 
    // Methods for/from SuperClass/Interfaces 
    // =========================================================== 

    @Override 
    public void setOnTouchListener(OnTouchListener listener) { 
     onTouchListener = listener; 
    } 

    @Override 
    public boolean onTouch(View view, MotionEvent ev) { 
     if (isPullToRefreshEnabled) { 
      // Returning true here stops the ListView being scrollable while we 
      // refresh 
      if (state == REFRESHING) { 
       return true; 
      } else { 
       return onAdapterViewTouch(view, ev); 
      } 
     } 
     return false; 
    } 

    /** 
    * This is implemented by derived classes to return the created AdapterView. 
    * If you need to use a custom AdapterView (such as a custom ListView), 
    * override this method and return an instance of your custom class. 
    * 
    * Be sure to set the ID of the view in this method, especially if you're 
    * using a ListActivity or ListFragment. 
    * 
    * @param context 
    * @param attrs 
    *   AttributeSet from wrapped class. Means that anything you 
    *   include in the XML layout declaration will be routed to the 
    *   AdapterView 
    * @return New instance of the AdapterView 
    */ 
    protected abstract T createAdapterView(Context context, AttributeSet attrs); 

    // =========================================================== 
    // Methods 
    // =========================================================== 

    protected final void resetHeader() { 
     state = PULL_TO_REFRESH; 
     initializeYsHistory(); 
     startY = -1; 
     headerImage.setVisibility(View.VISIBLE); 
     headerProgress.setVisibility(View.GONE); 

     smoothScrollTo(0); 
    } 

    private void init(Context context, AttributeSet attrs) { 
     setOrientation(LinearLayout.VERTICAL); 

     // Header 
     ViewGroup header = (ViewGroup) LayoutInflater.from(context).inflate(R.layout.pull_to_refresh_header, this, 
       false); 
     headerText = (TextView) header.findViewById(R.id.pull_to_refresh_text); 
     pullLabel = context.getString(R.string.pull_to_refresh_pull_label); 
     refreshingLabel = context.getString(R.string.pull_to_refresh_refreshing_label); 
     releaseLabel = context.getString(R.string.pull_to_refresh_release_label); 
     headerImage = (ImageView) header.findViewById(R.id.pull_to_refresh_image); 
     headerProgress = (ProgressBar) header.findViewById(R.id.pull_to_refresh_progress); 
     addView(header, ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); 
     measureView(header); 
     headerHeight = header.getMeasuredHeight(); 

     // AdapterView 
     // By passing the attrs, we can add ListView/GridView params via XML 
     adapterView = this.createAdapterView(context, attrs); 
     adapterView.setOnTouchListener(this); 
     addView(adapterView, ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT); 

     // Animations 
     flipAnimation = new RotateAnimation(0, -180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f); 
     flipAnimation.setInterpolator(new LinearInterpolator()); 
     flipAnimation.setDuration(250); 
     flipAnimation.setFillAfter(true); 

     reverseAnimation = new RotateAnimation(-180, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 
       0.5f); 
     reverseAnimation.setInterpolator(new LinearInterpolator()); 
     reverseAnimation.setDuration(250); 
     reverseAnimation.setFillAfter(true); 

     // Hide Header View 
     setPadding(getPaddingLeft(), -headerHeight, getPaddingRight(), getPaddingBottom()); 
    } 

    private void measureView(View child) { 
     ViewGroup.LayoutParams p = child.getLayoutParams(); 
     if (p == null) { 
      p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); 
     } 

     int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width); 
     int lpHeight = p.height; 
     int childHeightSpec; 
     if (lpHeight > 0) { 
      childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 
     } else { 
      childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 
     } 
     child.measure(childWidthSpec, childHeightSpec); 
    } 

    private boolean onAdapterViewTouch(View view, MotionEvent event) { 

     switch (event.getAction()) { 
      case MotionEvent.ACTION_MOVE: 
       updateEventStates(event); 

       if (isPullingDownToRefresh() && startY == -1) { 
        if (startY == -1) { 
         startY = event.getY(); 
        } 
        return false; 
       } 

       if (startY != -1 && !adapterView.isPressed()) { 
        pullDown(event, startY); 
        return true; 
       } 
       break; 
      case MotionEvent.ACTION_UP: 
       initializeYsHistory(); 
       startY = -1; 

       if (state == RELEASE_TO_REFRESH) { 
        setRefreshing(); 
        if (onRefreshListener != null) { 
         onRefreshListener.onRefresh(); 
        } 
       } else { 
        smoothScrollTo(0); 
       } 
       break; 
     } 

     if (null != onTouchListener) { 
      return onTouchListener.onTouch(view, event); 
     } 
     return false; 
    } 

    private void pullDown(MotionEvent event, float firstY) { 
     float averageY = average(lastYs); 

     int height = (int) (Math.max(averageY - firstY, 0)); 
     setHeaderScroll(height); 

     if (state == PULL_TO_REFRESH && headerHeight < height) { 
      state = RELEASE_TO_REFRESH; 
      headerText.setText(releaseLabel); 
      headerImage.clearAnimation(); 
      headerImage.startAnimation(flipAnimation); 
     } 
     if (state == RELEASE_TO_REFRESH && headerHeight >= height) { 
      state = PULL_TO_REFRESH; 
      headerText.setText(pullLabel); 
      headerImage.clearAnimation(); 
      headerImage.startAnimation(reverseAnimation); 
     } 
    } 

    private void setHeaderScroll(int y) { 
     scrollTo(0, -y); 
    } 

    private int getHeaderScroll() { 
     return -getScrollY(); 
    } 

    private void setRefreshing() { 
     state = REFRESHING; 
     headerText.setText(refreshingLabel); 
     headerImage.clearAnimation(); 
     headerImage.setVisibility(View.INVISIBLE); 
     headerProgress.setVisibility(View.VISIBLE); 
     smoothScrollTo(headerHeight); 
    } 

    private float average(float[] ysArray) { 
     float avg = 0; 
     for (int i = 0; i < EVENT_COUNT; i++) { 
      avg += ysArray[i]; 
     } 
     return avg/EVENT_COUNT; 
    } 

    private void initializeYsHistory() { 
     for (int i = 0; i < EVENT_COUNT; i++) { 
      lastYs[i] = 0; 
     } 
    } 

    private void updateEventStates(MotionEvent event) { 
     for (int i = 0; i < EVENT_COUNT - 1; i++) { 
      lastYs[i] = lastYs[i + 1]; 
     } 

     float y = event.getY(); 
     int top = adapterView.getTop(); 
     lastYs[EVENT_COUNT - 1] = y + top; 
    } 

    private boolean isPullingDownToRefresh() { 
     return isPullToRefreshEnabled && state != REFRESHING && isUserDraggingDownwards() && isFirstVisible(); 
    } 

    private boolean isFirstVisible() { 
     if (this.adapterView.getCount() == 0) { 
      return true; 
     } else if (adapterView.getFirstVisiblePosition() == 0) { 
      return adapterView.getChildAt(0).getTop() >= adapterView.getTop(); 
     } else { 
      return false; 
     } 
    } 

    private boolean isUserDraggingDownwards() { 
     return this.isUserDraggingDownwards(0, EVENT_COUNT - 1); 
    } 

    private boolean isUserDraggingDownwards(int from, int to) { 
     return lastYs[from] != 0 && lastYs[to] != 0 && Math.abs(lastYs[from] - lastYs[to]) > 10 
       && lastYs[from] < lastYs[to]; 
    } 

    private void smoothScrollTo(int y) { 
     if (null != currentSmoothScrollRunnable) { 
      currentSmoothScrollRunnable.stop(); 
     } 

     this.currentSmoothScrollRunnable = new SmoothScrollRunnable(handler, getHeaderScroll(), y); 
     handler.post(currentSmoothScrollRunnable); 
    } 

    // =========================================================== 
    // Inner and Anonymous Classes 
    // =========================================================== 

    public static interface OnRefreshListener { 

     public void onRefresh(); 

    } 

} 

Answer 1

さらに詳しい回答をするには、CustomPagerAdapterの実装を確認する必要があります。

しかしCustomPagerAdapterのコンストラクタは、パラメータとしてViewsの配列/コレクション/ベクトルがかかるため、Views論文CustomPagerAdapterのinstantiateItem方法（あなたのCustomPagerAdapterがFragmentPagerAdapterある場合やgetItem法）を使用することを前提として正しいだろう

ViewPagerのページを作成しますか？

もしそうなら、それはあなたの問題かもしれません。

変数はViewsであり、すでにレイアウトの一部です。この場合、その中のViewはmGroupListです。 mGroupListは、レイアウトの一部であるalreadyです。 View（この場合はmGroupList）を2つの異なる親の子にすることはできません。代わりに「発見」mGroupListの

、あなたのCustomPagerAdapter（いずれかのコードから、または適切なレイアウトXMLを膨らませることによって）のinstantiateItem方法でPullToRefreshGridView新ブランドを作成します。新しいPullToRefreshGridViewインスタンスは、そこに親がなく、ViewPagerが必要と判断したときにViewPagerの子になります。

物事をよりシンプルにするために、私はそのgetItem方法で適切なFragmentを返します。これは、代わりにFragmentPagerAdapterまたはFragmentStatePagerAdapterを使用することをお勧め。 Fragmentは、PullToRefreshGridViewを含むonCreateViewメソッドで正しいビューを返します。 https://developer.android.com/reference/android/support/v13/app/FragmentPagerAdapter.html