Java tutorial
/* * Copyright (C) 2012 Jake Wharton * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.viewpagerindicator.as.library.indicator; import android.content.Context; import android.content.res.Resources; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.drawable.Drawable; import android.os.Parcel; import android.os.Parcelable; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.ViewConfigurationCompat; import android.support.v4.view.ViewPager; import android.support.v7.widget.RecyclerView; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import com.viewpagerindicator.as.R; import com.viewpagerindicator.as.library.pageview.RecyclerViewPager; /** * Draws a line for each page. The current page line is colored differently * than the unselected page lines. */ public class RecyclerUnderlinePageIndicator extends View implements RecyclerPageIndicator { private static final int INVALID_POINTER = -1; private static final int FADE_FRAME_MS = 30; private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); private boolean mFades; private int mFadeDelay; private int mFadeLength; private int mFadeBy; private RecyclerView mRecyclerView; private ViewPager.OnPageChangeListener mListener; private int mCurrentPage; private float mPositionOffset; private int mTouchSlop; private float mLastMotionX = -1; private int mActivePointerId = INVALID_POINTER; private boolean mIsDragging; private int defaultSelectedColor; private final Runnable mFadeRunnable = new Runnable() { @Override public void run() { if (!mFades) return; final int alpha = Math.max(mPaint.getAlpha() - mFadeBy, 0); mPaint.setAlpha(alpha); invalidate(); if (alpha > 0) { postDelayed(this, FADE_FRAME_MS); } } }; public RecyclerUnderlinePageIndicator(Context context) { this(context, null); } public RecyclerUnderlinePageIndicator(Context context, AttributeSet attrs) { this(context, attrs, R.attr.vpiUnderlinePageIndicatorStyle); } public RecyclerUnderlinePageIndicator(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); if (isInEditMode()) return; final Resources res = getResources(); //Load defaults from resources final boolean defaultFades = res.getBoolean(R.bool.default_underline_indicator_fades); final int defaultFadeDelay = res.getInteger(R.integer.default_underline_indicator_fade_delay); final int defaultFadeLength = res.getInteger(R.integer.default_underline_indicator_fade_length); defaultSelectedColor = res.getColor(R.color.default_underline_indicator_selected_color); //Retrieve styles attributes TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.UnderlinePageIndicator, defStyle, 0); setFades(a.getBoolean(R.styleable.UnderlinePageIndicator_fades, defaultFades)); setSelectedColor(a.getColor(R.styleable.UnderlinePageIndicator_selectedColor, defaultSelectedColor)); setFadeDelay(a.getInteger(R.styleable.UnderlinePageIndicator_fadeDelay, defaultFadeDelay)); setFadeLength(a.getInteger(R.styleable.UnderlinePageIndicator_fadeLength, defaultFadeLength)); Drawable background = a.getDrawable(R.styleable.UnderlinePageIndicator_android_background); if (background != null) { setBackgroundDrawable(background); } a.recycle(); final ViewConfiguration configuration = ViewConfiguration.get(context); mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration); } public boolean getFades() { return mFades; } public void setFades(boolean fades) { if (fades != mFades) { mFades = fades; if (fades) { post(mFadeRunnable); } else { removeCallbacks(mFadeRunnable); mPaint.setAlpha(0xFF); invalidate(); } } } public int getFadeDelay() { return mFadeDelay; } public void setFadeDelay(int fadeDelay) { mFadeDelay = fadeDelay; } public int getFadeLength() { return mFadeLength; } public void setFadeLength(int fadeLength) { mFadeLength = fadeLength; mFadeBy = 0xFF / (mFadeLength / FADE_FRAME_MS); } public int getSelectedColor() { return mPaint.getColor(); } public void setSelectedColor(int selectedColor) { mPaint.setColor(selectedColor); invalidate(); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (mRecyclerView == null) { return; } final int count = mRecyclerView.getAdapter().getItemCount(); if (count == 0) { return; } if (mCurrentPage >= count) { setCurrentItem(count - 1); return; } final int paddingLeft = getPaddingLeft(); final float pageWidth = (getWidth() - paddingLeft - getPaddingRight()) / (1f * count); final float left = paddingLeft + pageWidth * (mCurrentPage + mPositionOffset); final float right = left + pageWidth; final float top = getPaddingTop(); final float bottom = getHeight() - getPaddingBottom(); mPaint.setColor(defaultSelectedColor); canvas.drawRect(left, top, right, bottom, mPaint); } public boolean onTouchEvent(MotionEvent ev) { if (super.onTouchEvent(ev)) { return true; } if ((mRecyclerView == null) || (mRecyclerView.getAdapter().getItemCount() == 0)) { return false; } final int action = ev.getAction() & MotionEventCompat.ACTION_MASK; switch (action) { case MotionEvent.ACTION_DOWN: mActivePointerId = MotionEventCompat.getPointerId(ev, 0); mLastMotionX = ev.getX(); break; case MotionEvent.ACTION_MOVE: { final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId); final float x = MotionEventCompat.getX(ev, activePointerIndex); final float deltaX = x - mLastMotionX; if (!mIsDragging) { if (Math.abs(deltaX) > mTouchSlop) { mIsDragging = true; } } if (mIsDragging) { mLastMotionX = x; } break; } case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: if (!mIsDragging) { final int count = mRecyclerView.getAdapter().getItemCount(); final int width = getWidth(); final float halfWidth = width / 2f; final float sixthWidth = width / 6f; if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) { if (action != MotionEvent.ACTION_CANCEL) { mRecyclerView.scrollToPosition(mCurrentPage - 1); } return true; } else if ((mCurrentPage < count - 1) && (ev.getX() > halfWidth + sixthWidth)) { if (action != MotionEvent.ACTION_CANCEL) { mRecyclerView.scrollToPosition(mCurrentPage + 1); } return true; } } mIsDragging = false; mActivePointerId = INVALID_POINTER; break; case MotionEventCompat.ACTION_POINTER_DOWN: { final int index = MotionEventCompat.getActionIndex(ev); mLastMotionX = MotionEventCompat.getX(ev, index); mActivePointerId = MotionEventCompat.getPointerId(ev, index); break; } case MotionEventCompat.ACTION_POINTER_UP: final int pointerIndex = MotionEventCompat.getActionIndex(ev); final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex); if (pointerId == mActivePointerId) { final int newPointerIndex = pointerIndex == 0 ? 1 : 0; mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex); } mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId)); break; } return true; } // @Override // public void setViewPager(ViewPager viewPager) { // if (mViewPager == viewPager) { // return; // } // if (mViewPager != null) { // //Clear us from the old pager. // mViewPager.setOnPageChangeListener(null); // } // if (viewPager.getAdapter() == null) { // throw new IllegalStateException("ViewPager does not have adapter instance."); // } // mViewPager = viewPager; // mViewPager.setOnPageChangeListener(this); // invalidate(); // post(new Runnable() { // @Override public void run() { // if (mFades) { // post(mFadeRunnable); // } // } // }); // } @Override public void setViewPager(RecyclerView view) { { if (mRecyclerView == view) { return; } if (mRecyclerView != null) { //Clear us from the old pager. wrapViewPager(mRecyclerView).clearOnPageChangedListeners(); wrapViewPager(mRecyclerView).clearOnScrollListeners(); } if (view.getAdapter() == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } mRecyclerView = view; wrapViewPager(mRecyclerView).addOnPageChangedListener(new RecyclerViewPager.OnPageChangedListener() { @Override public void OnPageChanged(int oldPosition, int newPosition) { mCurrentPage = newPosition; mPositionOffset = 0; invalidate(); mFadeRunnable.run(); notifyDataSetChanged(); if (mListener != null) { mListener.onPageSelected(newPosition); } } }); wrapViewPager(mRecyclerView).addOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { super.onScrollStateChanged(recyclerView, newState); if (mListener != null) { mListener.onPageScrollStateChanged(newState); } } @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); if (mListener != null) { mListener.onPageScrolled(wrapViewPager(mRecyclerView).getCurrentPosition(), 0f, dx); } } }); invalidate(); post(new Runnable() { @Override public void run() { if (mFades) { post(mFadeRunnable); } } }); } } @Override public void setViewPager(RecyclerView view, int initialPosition) { setViewPager(view); setCurrentItem(initialPosition); } @Override public void setCurrentItem(int item) { if (mRecyclerView == null) { throw new IllegalStateException("ViewPager has not been bound."); } mRecyclerView.scrollToPosition(item); mCurrentPage = item; invalidate(); } @Override public void notifyDataSetChanged() { invalidate(); } // @Override // public void onPageScrollStateChanged(int state) { // mScrollState = state; // // if (mListener != null) { // mListener.onPageScrollStateChanged(state); // } // } // // @Override // public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { // mCurrentPage = position; // mPositionOffset = positionOffset; // if (mFades) { // if (positionOffsetPixels > 0) { // removeCallbacks(mFadeRunnable); // mPaint.setAlpha(0xFF); // } else if (mScrollState != ViewPager.SCROLL_STATE_DRAGGING) { // postDelayed(mFadeRunnable, mFadeDelay); // } // } // invalidate(); // // if (mListener != null) { // mListener.onPageScrolled(position, positionOffset, positionOffsetPixels); // } // } // // @Override // public void onPageSelected(int position) { // if (mScrollState == ViewPager.SCROLL_STATE_IDLE) { // mCurrentPage = position; // mPositionOffset = 0; // invalidate(); // mFadeRunnable.run(); // } // if (mListener != null) { // mListener.onPageSelected(position); // } // } // @Override // public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) { // mListener = listener; // } @Override public void onRestoreInstanceState(Parcelable state) { SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); mCurrentPage = savedState.currentPage; requestLayout(); } @Override public Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState savedState = new SavedState(superState); savedState.currentPage = mCurrentPage; return savedState; } static class SavedState extends BaseSavedState { int currentPage; public SavedState(Parcelable superState) { super(superState); } private SavedState(Parcel in) { super(in); currentPage = in.readInt(); } @Override public void writeToParcel(Parcel dest, int flags) { super.writeToParcel(dest, flags); dest.writeInt(currentPage); } @SuppressWarnings("UnusedDeclaration") public static final Creator<SavedState> CREATOR = new Creator<SavedState>() { @Override public SavedState createFromParcel(Parcel in) { return new SavedState(in); } @Override public SavedState[] newArray(int size) { return new SavedState[size]; } }; } public void setmListener(ViewPager.OnPageChangeListener mListener) { this.mListener = mListener; } private RecyclerViewPager wrapViewPager(RecyclerView view) { if (view instanceof RecyclerViewPager) { return (RecyclerViewPager) view; } throw new IllegalArgumentException("this view is not RecyclerViewPager type"); } }