Java tutorial
/* * Copyright (C) 2012 www.amsoft.cn * * 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.bangqu.eshow.view.sliding; /* * Copyright (C) 2012 www.amsoft.cn * * 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. */ import android.content.Context; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewGroup; import android.widget.Scroller; // TODO: Auto-generated Javadoc /** * ??,?Touch?. * */ public class ESSlidingPageView extends ViewGroup { /** . */ private String TAG = ESSlidingPageView.class.getSimpleName(); /** . */ private boolean D = true; /** . */ private Scroller mScroller; /** . */ private VelocityTracker mVelocityTracker; /** View. */ public static final int SCREEN_STATE_NEXT = 0; /** ?View. */ public static final int SCREEN_STATE_PROVIOUS = 1; /** ???. */ private int mScreenState = SCREEN_STATE_PROVIOUS; /** View??. */ private int nextViewOffset = 50; /** ???. */ private OnPageChangeListener onPageChangeListener = null; /** ??. */ private boolean finish = true; /** * . * @param context the context */ public ESSlidingPageView(Context context) { super(context); mScroller = new Scroller(context); } /** * . * @param context the context * @param attrs the attrs */ public ESSlidingPageView(Context context, AttributeSet attrs) { super(context, attrs); } /** * ??View?. * * @param changed the changed * @param l the l * @param t the t * @param r the r * @param b the b */ @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { //? for (int i = 0; i < getChildCount(); i++) { View child = getChildAt(i); int height = child.getMeasuredHeight(); int width = child.getMeasuredWidth(); child.setFocusable(true); if (D) Log.d(TAG, "--onLayout--:" + width); if (i == 0) { child.layout(-nextViewOffset, 0, nextViewOffset + width, height); } else { child.layout(width - nextViewOffset, 0, 2 * width - nextViewOffset, height); } } } /** * ???View. * @param widthMeasureSpec the width measure spec * @param heightMeasureSpec the height measure spec * @see android.view.View#onMeasure(int, int) */ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (D) Log.d(TAG, "--onMeasure--"); int width = MeasureSpec.getSize(widthMeasureSpec); int height = MeasureSpec.getSize(heightMeasureSpec); setMeasuredDimension(width, height); for (int i = 0; i < getChildCount(); i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } } /** * View. */ public void showNext() { if (!finish || mScreenState == SCREEN_STATE_NEXT) { return; } finish = false; mScreenState = SCREEN_STATE_NEXT; if (onPageChangeListener != null) { onPageChangeListener.onPageSelected(1); } if (D) Log.d(TAG, "--showNext--:" + getScrollX() + " dx " + (getChildAt(1).getWidth() - 2 * nextViewOffset)); //?onlayout??? mScroller.startScroll(getScrollX(), 0, getChildAt(1).getWidth() - 2 * nextViewOffset, 0, 800); invalidate(); } /** * View. */ public void showPrevious() { if (!finish || mScreenState == SCREEN_STATE_PROVIOUS) { return; } mScreenState = SCREEN_STATE_PROVIOUS; if (onPageChangeListener != null) { onPageChangeListener.onPageSelected(0); } if (D) Log.d(TAG, "--showPrevious--:" + getScrollX() + " dx -" + getScrollX()); //onlayout0? mScroller.startScroll(getScrollX(), 0, -getScrollX(), 0, 800); invalidate(); } /** * ??. * @see android.view.View#computeScroll() */ public void computeScroll() { super.computeScroll(); if (mScroller.computeScrollOffset()) { scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } //? if (mScroller.getFinalX() == mScroller.getCurrX()) { finish = true; } } /** * ?. * @param event the event */ private void obtainVelocityTracker(MotionEvent event) { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(event); } /** * . */ private void releaseVelocityTracker() { if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } /** * ???. * @return the screen state */ public int getScreenState() { return mScreenState; } /** * View. * * @param view the view */ public void addContentView(View view) { addView(view, 0, getLayoutParams()); view.setOnFocusChangeListener(new OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { if (hasFocus) { showPrevious(); } } }); view.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { if (MotionEvent.ACTION_DOWN == event.getAction()) { showPrevious(); } return false; } }); } /** * View. * * @param view the view */ public void addNextView(View view) { addView(view, 1, getLayoutParams()); view.setOnFocusChangeListener(new OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { if (hasFocus) { showNext(); } } }); view.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { if (MotionEvent.ACTION_DOWN == event.getAction()) { showNext(); } return false; } }); } /** * Gets the next view offset. * * @return the next view offset */ public int getNextViewOffset() { return nextViewOffset; } /** * ??. * * @param nextViewOffset the new next view offset */ public void setNextViewOffset(int nextViewOffset) { this.nextViewOffset = nextViewOffset; } /** * Gets the on page change listener. * * @return the on page change listener */ public OnPageChangeListener getOnPageChangeListener() { return onPageChangeListener; } /** * ???. * * @param onPageChangeListener the new on page change listener */ public void setOnPageChangeListener(OnPageChangeListener onPageChangeListener) { this.onPageChangeListener = onPageChangeListener; } }