本文实例讲述了Android编程实现小说阅读器滑动效果的方法。分享给大家供大家参考，具体如下：
看过小说都知道小说阅读器翻页有好多种效果，比如仿真翻页，滑动翻页，等等。由于某种原因，突然想写一个简单点的滑动翻页效果。在这里写出来也没有什么意图，希望大家可以根据这个效果举一反三，写出其他的效果。图就不上了。
下面是代码：大家理解onTouch事件即可
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package com.example.testscroll.view; import android.content.Context; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.Scroller; public class FlipperLayout extends ViewGroup { private Scroller mScroller; private VelocityTracker mVelocityTracker; private int mVelocityValue = 0; /** 商定这个滑动是否有效的距离 */ private int limitDistance = 0; private int screenWidth = 0; /** 手指移动的方向 */ private static final int MOVE_TO_LEFT = 0; private static final int MOVE_TO_RIGHT = 1; private static final int MOVE_NO_RESULT = 2; /** 最后触摸的结果方向 */ private int mTouchResult = MOVE_NO_RESULT; /** 一开始的方向 */ private int mDirection = MOVE_NO_RESULT; /** 触摸的模式 */ private static final int MODE_NONE = 0; private static final int MODE_MOVE = 1; private int mMode = MODE_NONE; /** 滑动的view */ private View mScrollerView = null; /** 最上层的view（处于边缘的，看不到的） */ private View currentTopView = null; /** 显示的view，显示在屏幕 */ private View currentShowView = null; /** 最底层的view（看不到的） */ private View currentBottomView = null; public FlipperLayout(Context context) { super(context); init(context); } public FlipperLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(context); } public FlipperLayout(Context context, AttributeSet attrs) { super(context, attrs); init(context); } private void init(Context context) { mScroller = new Scroller(context); screenWidth = context.getResources().getDisplayMetrics().widthPixels; limitDistance = screenWidth / 3; } /*** * * @param listener * @param currentBottomView * 最底层的view，初始状态看不到 * @param currentShowView * 正在显示的View * @param currentTopView * 最上层的View，初始化时滑出屏幕 */ public void initFlipperViews(TouchListener listener, View currentBottomView, View currentShowView, View currentTopView) { this.currentBottomView = currentBottomView; this.currentShowView = currentShowView; this.currentTopView = currentTopView; setTouchResultListener(listener); addView(currentBottomView); addView(currentShowView); addView(currentTopView); /** 默认将最上层的view滑动的边缘（用于查看上一页） */ currentTopView.scrollTo(-screenWidth, 0); } @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.layout(0, 0, width, height); } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); 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); } } private int startX = 0; @Override public boolean dispatchTouchEvent(MotionEvent ev) { switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: if (!mScroller.isFinished()) { break; } startX = (int) ev.getX(); break; } return super.dispatchTouchEvent(ev); } @SuppressWarnings("deprecation") @Override public boolean onTouchEvent(MotionEvent event) { obtainVelocityTracker(event); switch (event.getAction()) { case MotionEvent.ACTION_MOVE: if (!mScroller.isFinished()) { return super.onTouchEvent(event); } if (startX == 0) { startX = (int) event.getX(); } final int distance = startX - (int) event.getX(); if (mDirection == MOVE_NO_RESULT) { if (mListener.whetherHasNextPage() && distance > 0) { mDirection = MOVE_TO_LEFT; } else if (mListener.whetherHasPreviousPage() && distance < 0) { mDirection = MOVE_TO_RIGHT; } } if (mMode == MODE_NONE && ((mDirection == MOVE_TO_LEFT && mListener.whetherHasNextPage()) || (mDirection == MOVE_TO_RIGHT && mListener .whetherHasPreviousPage()))) { mMode = MODE_MOVE; } if (mMode == MODE_MOVE) { if ((mDirection == MOVE_TO_LEFT && distance <= 0) || (mDirection == MOVE_TO_RIGHT && distance >= 0)) { mMode = MODE_NONE; } } if (mDirection != MOVE_NO_RESULT) { if (mDirection == MOVE_TO_LEFT) { if (mScrollerView != currentShowView) { mScrollerView = currentShowView; } } else { if (mScrollerView != currentTopView) { mScrollerView = currentTopView; } } if (mMode == MODE_MOVE) { mVelocityTracker.computeCurrentVelocity(1000, ViewConfiguration.getMaximumFlingVelocity()); if (mDirection == MOVE_TO_LEFT) { mScrollerView.scrollTo(distance, 0); } else { mScrollerView.scrollTo(screenWidth + distance, 0); } } else { final int scrollX = mScrollerView.getScrollX(); if (mDirection == MOVE_TO_LEFT && scrollX != 0 && mListener.whetherHasNextPage()) { mScrollerView.scrollTo(0, 0); } else if (mDirection == MOVE_TO_RIGHT && mListener.whetherHasPreviousPage() && screenWidth != Math.abs(scrollX)) { mScrollerView.scrollTo(-screenWidth, 0); } } } break; case MotionEvent.ACTION_UP: if (mScrollerView == null) { return super.onTouchEvent(event); } final int scrollX = mScrollerView.getScrollX(); mVelocityValue = (int) mVelocityTracker.getXVelocity(); // scroll左正，右负(),(startX + dx)的值如果为0，即复位 /* * android.widget.Scroller.startScroll( int startX, int startY, int * dx, int dy, int duration ) */ int time = 500; if (mMode == MODE_MOVE && mDirection == MOVE_TO_LEFT) { if (scrollX > limitDistance || mVelocityValue < -time) { // 手指向左移动，可以翻屏幕 mTouchResult = MOVE_TO_LEFT; if (mVelocityValue < -time) { time = 200; } mScroller.startScroll(scrollX, 0, screenWidth - scrollX, 0, time); } else { mTouchResult = MOVE_NO_RESULT; mScroller.startScroll(scrollX, 0, -scrollX, 0, time); } } else if (mMode == MODE_MOVE && mDirection == MOVE_TO_RIGHT) { if ((screenWidth - scrollX) > limitDistance || mVelocityValue > time) { // 手指向右移动，可以翻屏幕 mTouchResult = MOVE_TO_RIGHT; if (mVelocityValue > time) { time = 250; } mScroller.startScroll(scrollX, 0, -scrollX, 0, time); } else { mTouchResult = MOVE_NO_RESULT; mScroller.startScroll(scrollX, 0, screenWidth - scrollX, 0, time); } } resetVariables(); postInvalidate(); break; } return true; } private void resetVariables() { mDirection = MOVE_NO_RESULT; mMode = MODE_NONE; startX = 0; releaseVelocityTracker(); } private TouchListener mListener; private void setTouchResultListener(TouchListener listener) { this.mListener = listener; } @Override public void computeScroll() { super.computeScroll(); if (mScroller.computeScrollOffset()) { mScrollerView.scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } else if (mScroller.isFinished() && mListener != null && mTouchResult != MOVE_NO_RESULT) { if (mTouchResult == MOVE_TO_LEFT) { if (currentTopView != null) { removeView(currentTopView); } currentTopView = mScrollerView; currentShowView = currentBottomView; if (mListener.currentIsLastPage()) { final View newView = mListener.createView(mTouchResult); currentBottomView = newView; addView(newView, 0); } else { currentBottomView = new View(getContext()); currentBottomView.setVisibility(View.GONE); addView(currentBottomView, 0); } } else { if (currentBottomView != null) { removeView(currentBottomView); } currentBottomView = currentShowView; currentShowView = mScrollerView; if (mListener.currentIsFirstPage()) { final View newView = mListener.createView(mTouchResult); currentTopView = newView; currentTopView.scrollTo(-screenWidth, 0); addView(currentTopView); } else { currentTopView = new View(getContext()); currentTopView.scrollTo(-screenWidth, 0); currentTopView.setVisibility(View.GONE); addView(currentTopView); } } mTouchResult = MOVE_NO_RESULT; } } private void obtainVelocityTracker(MotionEvent event) { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(event); } private void releaseVelocityTracker() { if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } /*** * 用来实时回调触摸事件回调 * * @author freeson */ public interface TouchListener { /** 手指向左滑动，即查看下一章节 */ final int MOVE_TO_LEFT = 0; /** 手指向右滑动，即查看上一章节 */ final int MOVE_TO_RIGHT = 1; /** * 创建一个承载Text的View * * @param direction * {@link MOVE_TO_LEFT,MOVE_TO_RIGHT} * @return */ public View createView(final int direction); /*** * 当前页是否是第一页 * * @return */ public boolean currentIsFirstPage(); /*** * 当前页是否是最后一页 * * @return */ public boolean currentIsLastPage(); /** * 当前页是否有上一页（用来判断可滑动性） * * @return */ public boolean whetherHasPreviousPage(); /*** * 当前页是否有下一页（用来判断可滑动性） * * @return */ public boolean whetherHasNextPage(); } } |
Activity测试文件：
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package com.example.testscroll; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import android.app.Activity; import android.content.res.AssetManager; import android.os.Bundle; import android.os.Handler; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.widget.TextView; import com.example.testscroll.view.FlipperLayout; import com.example.testscroll.view.FlipperLayout.TouchListener; import com.example.testscrollactivity.R; public class MainActivity extends Activity implements OnClickListener, TouchListener { private String text = ""; private int textLenght = 0; private static final int COUNT = 400; private int currentTopEndIndex = 0; private int currentShowEndIndex = 0; private int currentBottomEndIndex = 0; private Handler handler = new Handler() { public void handleMessage(android.os.Message msg) { FlipperLayout rootLayout = (FlipperLayout) findViewById(R.id.container); View recoverView = LayoutInflater.from(MainActivity.this).inflate(R.layout.view_new, null); View view1 = LayoutInflater.from(MainActivity.this).inflate(R.layout.view_new, null); View view2 = LayoutInflater.from(MainActivity.this).inflate(R.layout.view_new, null); rootLayout.initFlipperViews(MainActivity.this, view2, view1, recoverView); textLenght = text.length(); System.out.println("----textLenght----->" + textLenght); TextView textView = (TextView) view1.findViewById(R.id.textview); if (textLenght > COUNT) { textView.setText(text.subSequence(0, COUNT)); textView = (TextView) view2.findViewById(R.id.textview); if (textLenght > (COUNT << 1)) { textView.setText(text.subSequence(COUNT, COUNT * 2)); currentShowEndIndex = COUNT; currentBottomEndIndex = COUNT << 1; } else { textView.setText(text.subSequence(COUNT, textLenght)); currentShowEndIndex = textLenght; currentBottomEndIndex = textLenght; } } else { textView.setText(text.subSequence(0, textLenght)); currentShowEndIndex = textLenght; currentBottomEndIndex = textLenght; } }; }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); new ReadingThread().start(); } @Override public void onClick(View v) { } @Override public View createView(final int direction) { String txt = ""; if (direction == TouchListener.MOVE_TO_LEFT) { currentTopEndIndex = currentShowEndIndex; final int nextIndex = currentBottomEndIndex + COUNT; currentShowEndIndex = currentBottomEndIndex; if (textLenght > nextIndex) { txt = text.substring(currentBottomEndIndex, nextIndex); currentBottomEndIndex = nextIndex; } else { txt = text.substring(currentBottomEndIndex, textLenght); currentBottomEndIndex = textLenght; } } else { currentBottomEndIndex = currentShowEndIndex; currentShowEndIndex = currentTopEndIndex; currentTopEndIndex = currentTopEndIndex - COUNT; txt = text.substring(currentTopEndIndex - COUNT, currentTopEndIndex); } View view = LayoutInflater.from(this).inflate(R.layout.view_new, null); TextView textView = (TextView) view.findViewById(R.id.textview); textView.setText(txt); System.out.println("-top->" + currentTopEndIndex + "-show->" + currentShowEndIndex + "--bottom-->" + currentBottomEndIndex); return view; } @Override public boolean whetherHasPreviousPage() { return currentShowEndIndex > COUNT; } @Override public boolean whetherHasNextPage() { return currentShowEndIndex < textLenght; } @Override public boolean currentIsFirstPage() { boolean should = currentTopEndIndex > COUNT; if (!should) { currentBottomEndIndex = currentShowEndIndex; currentShowEndIndex = currentTopEndIndex; currentTopEndIndex = currentTopEndIndex - COUNT; } return should; } @Override public boolean currentIsLastPage() { boolean should = currentBottomEndIndex < textLenght; if (!should) { currentTopEndIndex = currentShowEndIndex; final int nextIndex = currentBottomEndIndex + COUNT; currentShowEndIndex = currentBottomEndIndex; if (textLenght > nextIndex) { currentBottomEndIndex = nextIndex; } else { currentBottomEndIndex = textLenght; } } return should; } private class ReadingThread extends Thread { public void run() { AssetManager am = getAssets(); InputStream response; try { response = am.open("text.txt"); if (response != null) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); int i = -1; while ((i = response.read()) != -1) { baos.write(i); } text = new String(baos.toByteArray(), "UTF-8"); baos.close(); response.close(); handler.sendEmptyMessage(0); } } catch (IOException e) { e.printStackTrace(); } } } } |
xml布局文件：
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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" > <TextView android:id="@+id/textview" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1.0" android:background="#666666" android:gravity="center" android:text="新建的View" android:textColor="@android:color/white" android:textSize="16sp" android:visibility="visible" /> <View android:layout_width="5dp" android:layout_height="match_parent" android:background="#FFFF00" android:gravity="center" android:textSize="25sp" android:visibility="visible" /></LinearLayout> |
activity布局文件：
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<com.example.testscroll.view.FlipperLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container" android:layout_width="match_parent" android:layout_height="match_parent" > </com.example.testscroll.view.FlipperLayout> |
备注：上面为什么加一个速率计算器呢，其实只是为了识别这个动作是不是快速滑动的动作，就算滑动的距离不到屏幕的1/3，但是只要速率满足都可以判定改滑动是一个翻页的动作。
注意哦：这只是其中一个滑动的效果而已啊，不包括小说分章节的逻辑哦。虽然有些粗糙，但是还是有可以值得学习的地方，大家如果还有什么好的解决方案，可以一起讨论。
附上demo下载地址 点击下载demo。
希望本文所述对大家Android程序设计有所帮助。
