I am writing RecyclerViewRefresh after SwipeRefreshLayout.class. When I stretch the view until it moves, and then release, the view is reset to the original. The problem is that the view should start a timer, and then the reset timer. I could not find the reason.
Please tell me why offsetTopAndBottom () can automatically display the view in its original location. Thanks.
I am using setY () to solve this problem. But I also want to know why. And I read the source offsetTopAndBottom (), also cannot find any clue.
RecyclerViewRefresh Code:
public class RecyclerViewRefresh extends LinearLayout { private static final String LOG_TAG=RecyclerViewRefresh.class.getSimpleName(); private static final int INVALID_POINTER=-1; //Default offset in dips from the top of the view to where the progress //spinner should stop private static final int DEFAULT_CIRCLE_TARGET=64; private static final float DRAG_RATE=.5f; private View headerView,footerView,thisView; private View mTarget; //the target of the gesture private ImageView arrowIv; private TextView refreshTv; private ProgressBar progressBar; private OnPullToRefresh refreshListener=null; private OnDragToLoad loadListener=null; float startY=0; private int headerHeight=0; private boolean mReturningToStart; private boolean mRefreshing=false; private boolean mNestedScrollInProgress; private int mCurrentTargetOffsetTop; protected int mOriginalOffsetTop; private boolean mIsBeingDragged; private int mActivePointerId=INVALID_POINTER; private float mInitailDownY; private int mTouchSlop; private float mTotalDragDistance=-1; private float mInitialMotionY; private float mSpinnerFinalOffset; private boolean updateHeader=true; private Handler handler=new Handler(); private Timer timer; public RecyclerViewRefresh(Context context) { super(context); initView(context); } public RecyclerViewRefresh(Context context, AttributeSet attrs) { super(context, attrs); initView(context); } public RecyclerViewRefresh(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initView(context); } private void initView(Context context) { thisView=this; mTouchSlop= ViewConfiguration.get(context).getScaledTouchSlop(); headerView=LayoutInflater.from(context).inflate(R.layout.header_layout,null); footerView=LayoutInflater.from(context).inflate(R.layout.header_layout,null); measureView(headerView); arrowIv=(ImageView)headerView.findViewById(R.id.arrow); refreshTv=(TextView)headerView.findViewById(R.id.tip); progressBar=(ProgressBar)headerView.findViewById(R.id.progress); headerHeight=headerView.getMeasuredHeight(); LinearLayout.LayoutParams lp=new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, headerView.getMeasuredHeight()); this.addView(headerView,lp); setTopHeader(headerHeight); final DisplayMetrics metrics=getResources().getDisplayMetrics(); mSpinnerFinalOffset=DEFAULT_CIRCLE_TARGET*metrics.density; mTotalDragDistance=mSpinnerFinalOffset; } /** * 通知父布局，占用的宽，高； * * @param view */ private void measureView(View view) { ViewGroup.LayoutParams p = view.getLayoutParams(); if (p == null) { p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); } int width = ViewGroup.getChildMeasureSpec(0, 0, p.width); int height; int tempHeight = p.height; if (tempHeight > 0) { height = MeasureSpec.makeMeasureSpec(tempHeight, MeasureSpec.EXACTLY); } else { height = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } view.measure(width, height); } private void setTopHeader(int height) { if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.HONEYCOMB) { this.setY(-height); }else{ LayoutParams lp=new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,height); lp.topMargin=-height; this.setLayoutParams(lp); } headerView.invalidate(); } /** * Set the listener to be notified when a refresh is triggered via the * pull gesture. * @param listener */ public void setOnPullToRefresh(OnPullToRefresh listener) { this.refreshListener=listener; } /** * Set the listener to be notified when a load is triggered via the * drag gesture * @param listener */ public void setOnDragToLoad(OnDragToLoad listener) { this.loadListener=listener; } private void ensureTarget(){ if(mTarget==null){ for(int i=0;i<getChildCount();i++) { View child=getChildAt(i); if(child instanceof RecyclerView) { mTarget=child; break; } } } } /** * @return Whether it is possible for the child view of this layout to * scroll up.Override this if the child view is a custom view. */ public boolean canChildScrollUp(){ if(mTarget==null) { ensureTarget(); } if(Build.VERSION.SDK_INT<14) { if(mTarget instanceof AbsListView) { final AbsListView absListView=(AbsListView)mTarget; return absListView.getChildCount()>0 &&(absListView.getFirstVisiblePosition()>0 ||absListView.getChildAt(0).getTop()<absListView.getPaddingTop()); }else{ return ViewCompat.canScrollVertically(mTarget,-1)|| mTarget.getScrollY()>0; } }else{ return ViewCompat.canScrollVertically(mTarget,-1); } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { ensureTarget(); final int action=MotionEventCompat.getActionMasked(ev); if(mReturningToStart && action == MotionEvent.ACTION_DOWN){ mReturningToStart = false; } if(!isEnabled() || mReturningToStart || canChildScrollUp() ||mRefreshing || mNestedScrollInProgress){ return false; } switch (action){ case MotionEvent.ACTION_DOWN: setTargetOffsetTopAndBottom(mOriginalOffsetTop-headerView.getTop(),true); mActivePointerId=MotionEventCompat.getPointerId(ev,0); mIsBeingDragged=false; final float initialDownY=getMotionEventY(ev,mActivePointerId); if(initialDownY==-1){ return false; } mInitailDownY=initialDownY; updateHeader=true; break; case MotionEvent.ACTION_MOVE: if(mActivePointerId==INVALID_POINTER){ Log.e(LOG_TAG, "Got ACTION_MOVE event but don't have an active pointer id."); return false; } final float y=getMotionEventY(ev,mActivePointerId); if(y==-1){ return false; } final float yDiff=y-mInitailDownY; if(yDiff>mTouchSlop && !mIsBeingDragged){ mInitialMotionY=mInitailDownY+mTouchSlop; mIsBeingDragged=true; } break; case MotionEventCompat.ACTION_POINTER_UP: onSecondaryPointerUp(ev); break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: mIsBeingDragged=false; mActivePointerId=INVALID_POINTER; break; } return mIsBeingDragged; } private float getMotionEventY(MotionEvent ev,int activePointerId){ final int index=MotionEventCompat.findPointerIndex(ev,activePointerId); if(index<0){ return -1; } return MotionEventCompat.getY(ev,index); } private void setTargetOffsetTopAndBottom(int offset,boolean requiresUpdate){ if(this.getTop()<headerHeight+5) { this.offsetTopAndBottom(offset); mCurrentTargetOffsetTop=this.getTop(); if(requiresUpdate && Build.VERSION.SDK_INT<11){ invalidate(); } if(this.getTop()>headerHeight) { if(updateHeader){ updateHeader=false; refreshTv.setText(getResources().getText(R.string.releasetorefresh)); RotateAnimation animation=new RotateAnimation(0,180, Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f); animation.setDuration(800); animation.setFillAfter(true); arrowIv.startAnimation(animation); } } } } private void onSecondaryPointerUp(MotionEvent ev){ final int pointerIndex=MotionEventCompat.getActionIndex(ev); final int pointerId=MotionEventCompat.getPointerId(ev,pointerIndex); if(pointerId==mActivePointerId){ //This was our active pointer going up. Choose a new //active pointer and adjust accordingly. final int newPointerIndex=pointerIndex==0?1:0; mActivePointerId=MotionEventCompat.getPointerId(ev,newPointerIndex); } } @Override public boolean onTouchEvent(MotionEvent event) { final int action=MotionEventCompat.getActionMasked(event); int pointerIndex=-1; if(mReturningToStart&&action==MotionEvent.ACTION_DOWN){ mReturningToStart=false; } if(!isEnabled() || mReturningToStart || canChildScrollUp() || mNestedScrollInProgress){ //Fail fast if we're not in a state where a swipe is possible return false; } switch(action){ case MotionEvent.ACTION_DOWN: mActivePointerId=MotionEventCompat.getPointerId(event,0); mIsBeingDragged=false; break; case MotionEvent.ACTION_MOVE:{ pointerIndex=MotionEventCompat.findPointerIndex(event,mActivePointerId); if(pointerIndex<0){ Log.e(LOG_TAG, "Got ACTION_MOVE event but have an invalid active pointer id."); return false; } final float y=MotionEventCompat.getY(event,pointerIndex); final float overscrollTop=(y-mInitialMotionY)*DRAG_RATE; if(mIsBeingDragged){ if(overscrollTop>0){ moveSpinner(overscrollTop); }else{ return false; } } break; } case MotionEventCompat.ACTION_POINTER_DOWN:{ pointerIndex=MotionEventCompat.getActionIndex(event); if(pointerIndex<0){ Log.e(LOG_TAG, "Got ACTION_POINTER_DOWN event but have an invalid action index."); return false; } mActivePointerId=MotionEventCompat.getPointerId(event,pointerIndex); break; } case MotionEvent.ACTION_POINTER_UP: onSecondaryPointerUp(event); break; case MotionEvent.ACTION_UP:{ pointerIndex=MotionEventCompat.findPointerIndex(event,mActivePointerId); if(pointerIndex<0){ Log.e(LOG_TAG, "Got ACTION_UP event but don't have an active pointer id."); return false; } final float y=MotionEventCompat.getY(event,pointerIndex); mIsBeingDragged=false; finishSpinner(); mActivePointerId=INVALID_POINTER; return false; } case MotionEvent.ACTION_CANCEL: return false; } return true; } private void moveSpinner(float overscrollTop){ float originalDragPercent=overscrollTop/mTotalDragDistance; float dragPercent=Math.min(1f,Math.abs(originalDragPercent)); float adjustedPercent=(float)Math.max(dragPercent-.4,0)*5/3; float extraOS=Math.abs(overscrollTop)-mTotalDragDistance; float slingshotDist=mSpinnerFinalOffset; float tensionSlingshotPercent=Math.max(0,Math.min(extraOS,slingshotDist*2)/slingshotDist); float tensionPercent=(float)((tensionSlingshotPercent/4)-Math.pow( (tensionSlingshotPercent/4),2))*2f; float extraMove=(slingshotDist)*tensionPercent*2; int targetY=mOriginalOffsetTop+(int)((slingshotDist*dragPercent)+extraMove); setTargetOffsetTopAndBottom(targetY-mCurrentTargetOffsetTop,true); } private void finishSpinner(){ if(this.getTop()>headerHeight){ setRefreshing(true,true); }else{ //cancel refresh mRefreshing=false; animateOffsetToStartPosition(); } } private void setRefreshing(boolean refreshing,final boolean notify) { if(mRefreshing!=refreshing){ ensureTarget(); mRefreshing=refreshing; if(mRefreshing){ refreshListener.onRefresh(); arrowIv.setVisibility(View.GONE); progressBar.setVisibility(View.VISIBLE); }else{ arrowIv.setVisibility(View.VISIBLE); progressBar.setVisibility(View.GONE); animateOffsetToStartPosition(); } } } public void setRefreshing(boolean refreshing){ if(!refreshing){ setRefreshing(refreshing,false); } } private void animateOffsetToStartPosition(){ refreshTv.setText(getResources().getText(R.string.pulltorefresh)); arrowIv.clearAnimation(); Log.d(LOG_TAG,"getTop="+this.getTop()+" timer="+((timer==null)?"null":"notnumm")); if(timer==null&&this.getTop()>0) { timer=new Timer(); timer.schedule(new TimerTask() { @Override public void run() { handler.post(new Runnable() { @Override public void run() { if(thisView.getTop()>0) { thisView.offsetTopAndBottom(-1); mCurrentTargetOffsetTop = headerView.getTop(); if ( Build.VERSION.SDK_INT < 11) { invalidate(); } }else{ Log.d(LOG_TAG,"cancel"); timer.cancel(); timer=null; } } }); } },10,10); } } /** * Classes that wish to be notified when the pull gesture correctly * triggers a refresh should implement this interface. */ public interface OnPullToRefresh{ public void onRefresh(); } /** * Classes that wish to be notified when the drag gesture correctly * triggers a load should implement this interface. */ public interface OnDragToLoad{ public void onLoad(); }}