Java tutorial
/* * Copyright (C) 2013 Lee Hong (http://blog.csdn.net/leehong2005) * * 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. */ /* * 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.lee.sdk.widget.viewpager; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; 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.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import com.lee.sdk.R; /** * Draws a line for each page. The current page line is colored differently * than the unselected page lines. */ public class DrawablePageIndicator extends View implements PageIndicator { private static final int INVALID_POINTER = -1; private ViewPager mViewPager; private ViewPager.OnPageChangeListener mListener; private int mScrollState; private int mCurrentPage; private float mPositionOffset; private int mTouchSlop; private float mLastMotionX = -1; private int mActivePointerId = INVALID_POINTER; private boolean mIsDragging; private float mShadowLeft; private float mShadowRight; private Drawable mDrawable; public DrawablePageIndicator(Context context) { this(context, null); } public DrawablePageIndicator(Context context, AttributeSet attrs) { this(context, attrs, R.attr.vpiDrawablePageIndicatorStyle); } @SuppressWarnings("deprecation") public DrawablePageIndicator(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); if (isInEditMode()) return; //Retrieve styles attributes TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.DrawablePageIndicator, defStyle, 0); Drawable background = a.getDrawable(R.styleable.DrawablePageIndicator_android_background); if (background != null) { setBackgroundDrawable(background); } mShadowLeft = a.getDimension(R.styleable.DrawablePageIndicator_shadow_left, 0.0f); mShadowRight = a.getDimension(R.styleable.DrawablePageIndicator_shadow_right, 0.0f); mDrawable = a.getDrawable(R.styleable.DrawablePageIndicator_android_src); if (mDrawable == null) { mDrawable = new ColorDrawable(Color.WHITE); } a.recycle(); final ViewConfiguration configuration = ViewConfiguration.get(context); mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration); } public void setIndicatorDrawable(Drawable drawable) { mDrawable = drawable; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (mViewPager == null) { return; } final int count = mViewPager.getAdapter().getCount(); 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(); mDrawable.setBounds((int) (left - mShadowLeft), (int) top, (int) (right + mShadowRight), (int) bottom); mDrawable.draw(canvas); } public boolean onTouchEvent(MotionEvent ev) { if (super.onTouchEvent(ev)) { return true; } if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 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; if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) { mViewPager.fakeDragBy(deltaX); } } break; } case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: if (!mIsDragging) { // final int count = mViewPager.getAdapter().getCount(); // 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) { // mViewPager.setCurrentItem(mCurrentPage - 1); // } // return true; // } else if ((mCurrentPage < count - 1) && (ev.getX() > halfWidth + sixthWidth)) { // if (action != MotionEvent.ACTION_CANCEL) { // mViewPager.setCurrentItem(mCurrentPage + 1); // } // return true; // } if (action != MotionEvent.ACTION_CANCEL) { final int count = mViewPager.getAdapter().getCount(); final int width = getWidth(); final int pageWidth = width / count; int downPage = (int) (ev.getX() / pageWidth); if (downPage != mCurrentPage) { mViewPager.setCurrentItem(downPage); return true; } } } mIsDragging = false; mActivePointerId = INVALID_POINTER; if (mViewPager.isFakeDragging()) mViewPager.endFakeDrag(); 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(); } @Override public void setViewPager(ViewPager view, int initialPosition) { setViewPager(view); setCurrentItem(initialPosition); } @Override public void setCurrentItem(int item) { if (mViewPager == null) { throw new IllegalStateException("ViewPager has not been bound."); } mViewPager.setCurrentItem(item, false); 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; 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(); } 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); } 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]; } }; } } //CHECKSTYLE:ON