記得之前京東首頁有一個效果,有一個畫軸,然后可以滾動畫軸,去打開畫(不知道怎么去形容這個效果,就叫做畫軸效果吧- -!),然后去做相關操作,剛開始看到這個效果,想法是動態的去改變一個ImageView的高度,基本效果也就出來了,不過滾動部分的內容,當時接觸的也不是很多,只是看過一些大牛的博客,略微了解了一點,當時也忙著寫項目,也就沒去多想,前些天忽然想到這個效果,就想著實現一下,不過京東新版本好像去掉這個東西了,只能憑著自己的記憶來大概搞一下,也是對滑動這部分內容的一個小練習吧.
先看一下效果圖:
一、需求分析
看到效果之后,先來分析一下:
首先是需要一個可以滑動的畫軸,并且這個畫軸需要一定的滑動空間,有滑動的效果,這個用Scroller幫助完成就可以了.
然后看一下畫軸點擊移動時候的背景圖,是跟隨畫軸移動,動態改變高度的.這個用一個ImageView來搞定,設置ImageView的scaleType就可以了,不過這個地方有一些小問題,下面會說.
二、具體實現
簡單分析完,來實現一下,先來做一下畫軸.創建一個ScrollPaintView繼承自RelativeLayout,因為需要一定的滑動空間,所以需要是一個ViewGroup.
ScrollPaintView的一些基本屬性:
public class ScrollPaintView extends RelativeLayout { /** * TAG */ private static final String TAG = "ScrollPaintView"; /** * 默認滾軸高度 */ private final int DEFAULT_PAINT_SCROLL_HEIGHT = 25; /** * 默認滾動的速度 */ private final int DEFAULT_SCROLL_SPEED = 1000; /** * 默認分割點高度 */ private final int DEFAULT_PARTITION_NODE = 150; /** * 默認畫軸文字大小 */ private final int DEFAULT_PAINT_SCROLL_TXT_SIZE = 16; /** * Scroller */ private Scroller mScroller; /** * 滾軸Iv */ private ImageView mPaintScrollImageView; /** * 滾軸Tv */ private TextView mPaintScrollTextView; /** * 圖畫Iv */ private ImageView mPaintView; /** * 畫軸圖 */ private Bitmap mPaintScrollBp; /** * 畫軸高度 */ private int mPaintIvHeight; /** * 畫軸文字 */ private String mPaintScrollTxt; /** * 畫軸文字大小 */ private float mPaintScrollTxtSize; /** * 畫軸文字顏色 */ private int mPaintScrollTxtColor; /** * 圖畫開始時的高度 */ private int mPaintStartHeight; /** * 上一次獲取的Y */ private int mLastY; /** * 滾動速度 */ private int mScrollSpeed; /** * 分隔節點 */ private int partitionNode; /** * 是否是向上滾動 */ private boolean isScrllerTop = false; /** * 是否正在點擊 */ private boolean isClick = false; /** * 布局參數 */ private LayoutParams lpp; /** * 屏幕高度 */ private int screenHeight; /** * 屏幕寬度 */ private int screenWidth; /** * 回調監聽 */ private ScrollPaintCompleteListener listener; /** * 上一次滾動的Y值 */ private int lastScrollY; /** * 構造方法 */ public ScrollPaintView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); // 獲取屬性 TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ScrollPaintView); mPaintIvHeight = (int) ta.getDimension(R.styleable.ScrollPaintView_paintScrollHeight, TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_DIP, DEFAULT_PAINT_SCROLL_HEIGHT, getResources().getDisplayMetrics())); mScrollSpeed = ta.getInteger(R.styleable.ScrollPaintView_scrollSpeed, DEFAULT_SCROLL_SPEED); partitionNode = ta.getInteger(R.styleable.ScrollPaintView_scrollPartitionNode, DEFAULT_PARTITION_NODE); mPaintScrollBp = drawableToBitamp(ta.getDrawable(R.styleable.ScrollPaintView_paintScrollSrc)); mPaintScrollTxt = ta.getString(R.styleable.ScrollPaintView_paintScrollTxt); mPaintScrollTxtColor = ta.getColor(R.styleable.ScrollPaintView_paintScrollTxtColor, Color.BLACK); mPaintScrollTxtSize = px2sp(ta.getDimensionPixelSize(R.styleable.ScrollPaintView_paintScrollTxtSize, DEFAULT_PAINT_SCROLL_TXT_SIZE)); ta.recycle(); }}看一下創建畫軸:
/** * 創建滾軸 */ private void makePaintScroll() { // 如果已經存在,則不再創建 if (null != mPaintScrollImageView || null != mPaintScrollTextView) { return; } // 創建滾軸 mPaintScrollImageView = new ImageView(getContext()); LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); lp.height = mPaintIvHeight; mPaintScrollImageView.setLayoutParams(lp); mPaintScrollImageView.setScaleType(ImageView.ScaleType.FIT_XY); mPaintScrollImageView.setImageBitmap(null == mPaintScrollBp ? makeDefaultScroll() : mPaintScrollBp); addView(mPaintScrollImageView); // 創建文字 mPaintScrollTextView = new TextView(getContext()); LayoutParams lpt = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); lpt.height = mPaintIvHeight; mPaintScrollTextView.setLayoutParams(lpt); mPaintScrollTextView.setText(null == mPaintScrollTxt ? "" : mPaintScrollTxt); mPaintScrollTextView.setTextSize(mPaintScrollTxtSize); mPaintScrollTextView.setTextColor(mPaintScrollTxtColor); mPaintScrollTextView.setGravity(Gravity.CENTER); addView(mPaintScrollTextView); } /** * 設置默認的滾軸 * * @return */ private Bitmap makeDefaultScroll() { Bitmap defaultBp = Bitmap.createBitmap(screenWidth, mPaintIvHeight, Bitmap.Config.ARGB_8888); //填充顏色 defaultBp.eraseColor(Color.parseColor("#FF0000")); return defaultBp; }創建了一個畫軸ImageView和一個文字TextView作為初始的畫軸,如果沒有傳入畫軸的圖片,則默認去創建一個畫軸.不難理解,接著去配合Scroller,讓畫軸滾動起來.
簡單滾動:
/** * 處理View */ private void handleView() { // 初始化Scroller mScroller = new Scroller(getContext()); // 畫軸點擊效果 mPaintScrollImageView.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent event) { int x = (int) event.getRawX(); int y = (int) event.getRawY(); int action = event.getAction(); switch (action) { case MotionEvent.ACTION_DOWN: isClick = true; mLastY = y; if (!mScroller.isFinished()) { // 如果上次的調用沒有執行完就取消。 mScroller.abortAnimation(); } return true; case MotionEvent.ACTION_MOVE: // 移動的距離 int dy = y - mLastY; mLastY = y; // 滑動 scrollBy(0, -dy); return true; case MotionEvent.ACTION_UP: mScroller.startScroll(getScrollX(), getScrollY(), -getScrollX(), -getScrollY(), 1000); invalidate(); return true; } return false; } }); } /** * 滑動處理 */ @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { // 計算新位置，并判斷上一個滾動是否完成。 scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); invalidate(); } }這樣滑動處理就做完了,在布局中引用一下,看一下效果
activity_main:
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#eeeeee" tools:context="com.example.junweiliu.scrollpaintdemo.MainActivity"> <!--畫軸控件--> <com.example.junweiliu.scrollpaintdemo.widget.ScrollPaintView android:id="@+id/spv_paint" android:layout_width="match_parent" android:layout_height="match_parent" app:paintScrollHeight="25dp" app:paintScrollSrc="@mipmap/paint_scroll_img" app:paintScrollTxt="拉我看看" app:paintScrollTxtColor="#FF000000" app:paintScrollTxtSize="16sp" > </com.example.junweiliu.scrollpaintdemo.widget.ScrollPaintView></RelativeLayout>
效果圖:
滾動條基本能用了,接著來設置一個ImageView來配合使用下,先獲取到一個ImageView,然后拖動畫軸時,來動態改變ImageView的高度,在做這部分內容前,先來考慮下,因為需求需要的是圖畫整體不會變形,是一點一點拉開的感覺,就像是打開一幅畫一樣,那么用哪種scaleType能滿足呢.試了好多種,來分別看一下:
相關代碼:
提供一個設置ImageView的方法
在MotionEvent.ACTION_MOVE:中動態改變ImageView的高度
滑動時動態改變ImageView的高度
/** * 設置paintView * * @param paintView */ public void setPaintView(ImageView paintView) { if (null == paintView) { Log.e(TAG, "設置的View為空"); return; } mPaintView = paintView; }MotionEvent.ACTION_MOVE:
// 滑動處理 case MotionEvent.ACTION_MOVE: ... // 動態改變高度 if (Math.abs(getScrollY()) > 0) { lpp.height = mPaintStartHeight + Math.abs(getScrollY()); mPaintView.setLayoutParams(lpp); }滑動處理:
/** * 滑動處理 */ @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { // 計算新位置，并判斷上一個滾動是否完成。 // 請求處理點擊事件,防止父控件滑動 requestDisallowInterceptTouchEvent(true); scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); // 重新設置顯示的控件高度 if (0 < Math.abs(mScroller.getCurrY())) { if (!isScrllerTop) { lpp.height = mPaintStartHeight + Math.abs(mScroller.getCurrY()) + mPaintIvHeight / 2; } else { lpp.height = mPaintStartHeight + Math.abs(mScroller.getCurrY()) - mPaintIvHeight / 2; } } else { lpp.height = mPaintStartHeight; } mPaintView.setLayoutParams(lpp); invalidate(); }}設置不同scaleType效果,簡單試幾個效果:
fitXY:
centerCrop:
matrix:
觀察一下,好像那個效果都不是很好,不過matrix拉開的效果和預期需要的是一樣的,不過用matrix之后,就沒有辦法設置其他scaleType了,沒辦法把圖片進行縮放了,這腫么辦呢,其實很簡單,只需要把顯示的圖片提前進行一下縮放就可以了.
處理圖片相關:
/** * 設置paintView * * @param paintView */ public void setPaintView(ImageView paintView) { if (null == paintView) { Log.e(TAG, "設置的View為空"); return; } // 處理圖片,對圖片按照屏幕寬高比進行縮放 Bitmap bp = drawableToBitamp(paintView.getDrawable()); paintView.setImageBitmap(scaleBitmal(bp)); // 設置縮放形式 paintView.setScaleType(ImageView.ScaleType.MATRIX); mPaintView = paintView; } /** * drawable轉bitmap * * @param drawable * @return */ private Bitmap drawableToBitamp(Drawable drawable) { if (null == drawable) { return null; } if (drawable instanceof BitmapDrawable) { BitmapDrawable bd = (BitmapDrawable) drawable; return bd.getBitmap(); } int w = drawable.getIntrinsicWidth(); int h = drawable.getIntrinsicHeight(); Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); drawable.setBounds(0, 0, w, h); drawable.draw(canvas); return bitmap; } /** * 按照屏幕寬高縮放圖片 * * @param bp * @return */ private Bitmap scaleBitmal(Bitmap bp) { // 寬度比例 float scaleW = (float) screenWidth / (float) bp.getWidth(); // 高度比例 float scaleH = (float) screenHeight / (float) bp.getHeight(); // 矩陣,用于縮放圖片 Matrix matrix = new Matrix(); matrix.postScale(scaleW, scaleH); // 縮放后的圖片 Bitmap scaleBp = Bitmap.createBitmap(bp, 0, 0, bp.getWidth(), bp.getHeight(), matrix, true); return scaleBp; }看一下效果:
效果還不錯,接下來就是做一下細節上的處理,設置一個臨界點,讓畫軸向上或者向下滾動,設置邊界點,讓畫軸不越界等等.還有一般都是在ScrollView中使用到這個效果,所以要去處理一下事件沖突,當然還有去重寫一下onMeasure方法,不然會出現不顯示的情況.(相信大家也遇到過ScrollView里邊嵌套ListView導致ListView顯示不全)這里就不再詳細介紹了.直接貼下代碼.
三、完整代碼
MainActivity:
package com.example.junweiliu.scrollpaintdemo;import android.content.Intent;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;import com.example.junweiliu.scrollpaintdemo.widget.ScrollPaintView;public class MainActivity extends AppCompatActivity { private static final String TAG = "MainActivity"; /** * 需要顯示的IV */ private ImageView mPaintIv; /** * 畫軸 */ private ScrollPaintView mScrollPaintView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); } /** * 初始化控件 */ private void initView() { mPaintIv = (ImageView) findViewById(R.id.iv_paint); mScrollPaintView = (ScrollPaintView) findViewById(R.id.spv_paint); mScrollPaintView.setPaintView(mPaintIv); mPaintIv.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Toast.makeText(MainActivity.this, "功夫!", Toast.LENGTH_SHORT).show(); } }); mScrollPaintView.setScrollPaintCompleteListener(new ScrollPaintView.ScrollPaintCompleteListener() { @Override public void onScrollTouch(TextView tv) { mPaintIv.setVisibility(View.VISIBLE); } @Override public void onScrollTop(TextView tv) {// Log.e(TAG, "收縮了"); tv.setText("拉我看看"); if (View.VISIBLE == mPaintIv.getVisibility()) { mPaintIv.setVisibility(View.GONE); } } @Override public void onScrollBottom(TextView tv) {// Log.e(TAG, "展開了"); tv.setText("到底了"); Intent intent = new Intent(MainActivity.this, DetailActivity.class); startActivity(intent); // 延遲800毫秒重置位置 new Handler(new Handler.Callback() { @Override public boolean handleMessage(Message message) { mScrollPaintView.replaceScroll(); return false; } }).sendEmptyMessageDelayed(0, 600); } @Override public void onScrollMove(TextView tv) {// Log.e(TAG, "移動了"); tv.setText("請上下拖動"); } }); }}ScrollPaintView:
package com.example.junweiliu.scrollpaintdemo.widget;import android.app.Activity;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Rect;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.util.Log;import android.util.TypedValue;import android.view.Gravity;import android.view.MotionEvent;import android.view.View;import android.widget.ImageView;import android.widget.RelativeLayout;import android.widget.Scroller;import android.widget.TextView;import com.example.junweiliu.scrollpaintdemo.R;/** * Created by junweiliu on 16/12/10. */public class ScrollPaintView extends RelativeLayout { /** * TAG */ private static final String TAG = "ScrollPaintView"; /** * 默認滾軸高度 */ private final int DEFAULT_PAINT_SCROLL_HEIGHT = 25; /** * 默認滾動的速度 */ private final int DEFAULT_SCROLL_SPEED = 1000; /** * 默認分割點高度 */ private final int DEFAULT_PARTITION_NODE = 150; /** * 默認畫軸文字大小 */ private final int DEFAULT_PAINT_SCROLL_TXT_SIZE = 16; /** * Scroller */ private Scroller mScroller; /** * 滾軸Iv */ private ImageView mPaintScrollImageView; /** * 滾軸Tv */ private TextView mPaintScrollTextView; /** * 圖畫Iv */ private ImageView mPaintView; /** * 畫軸圖 */ private Bitmap mPaintScrollBp; /** * 畫軸高度 */ private int mPaintIvHeight; /** * 畫軸文字 */ private String mPaintScrollTxt; /** * 畫軸文字大小 */ private float mPaintScrollTxtSize; /** * 畫軸文字顏色 */ private int mPaintScrollTxtColor; /** * 圖畫開始時的高度 */ private int mPaintStartHeight; /** * 上一次獲取的Y */ private int mLastY; /** * 滾動速度 */ private int mScrollSpeed; /** * 分隔節點 */ private int partitionNode; /** * 是否是向上滾動 */ private boolean isScrllerTop = false; /** * 是否正在點擊 */ private boolean isClick = false; /** * 布局參數 */ private LayoutParams lpp; /** * 屏幕高度 */ private int screenHeight; /** * 屏幕寬度 */ private int screenWidth; /** * 回調監聽 */ private ScrollPaintCompleteListener listener; /** * 上一次滾動的Y值 */ private int lastScrollY; /** * 回調接口 */ public interface ScrollPaintCompleteListener { /** * 點擊時的回調 */ public void onScrollTouch(TextView tv); /** * 收縮時的回調 */ public void onScrollTop(TextView tv); /** * 展開時的回調 */ public void onScrollBottom(TextView tv); /** * 滾動中的回調 */ public void onScrollMove(TextView tv); } public ScrollPaintView(Context context) { this(context, null); } public ScrollPaintView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public ScrollPaintView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); // 獲取屬性 TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ScrollPaintView); mPaintIvHeight = (int) ta.getDimension(R.styleable.ScrollPaintView_paintScrollHeight, TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_DIP, DEFAULT_PAINT_SCROLL_HEIGHT, getResources().getDisplayMetrics())); mScrollSpeed = ta.getInteger(R.styleable.ScrollPaintView_scrollSpeed, DEFAULT_SCROLL_SPEED); partitionNode = ta.getInteger(R.styleable.ScrollPaintView_scrollPartitionNode, DEFAULT_PARTITION_NODE); mPaintScrollBp = drawableToBitamp(ta.getDrawable(R.styleable.ScrollPaintView_paintScrollSrc)); mPaintScrollTxt = ta.getString(R.styleable.ScrollPaintView_paintScrollTxt); mPaintScrollTxtColor = ta.getColor(R.styleable.ScrollPaintView_paintScrollTxtColor, Color.BLACK); mPaintScrollTxtSize = px2sp(ta.getDimensionPixelSize(R.styleable.ScrollPaintView_paintScrollTxtSize, DEFAULT_PAINT_SCROLL_TXT_SIZE)); ta.recycle(); init(); makePaintScroll(); handleView(); } /** * 設置paintView * * @param paintView */ public void setPaintView(ImageView paintView) { if (null == paintView) { Log.e(TAG, "設置的View為空"); return; } // 處理圖片,對圖片按照屏幕寬高比進行縮放 Bitmap bp = drawableToBitamp(paintView.getDrawable()); paintView.setImageBitmap(scaleBitmal(bp)); // 設置縮放形式 paintView.setScaleType(ImageView.ScaleType.MATRIX); mPaintView = paintView; } /** * 設置回調 */ public void setScrollPaintCompleteListener(ScrollPaintCompleteListener listener) { if (null != listener) { this.listener = listener; } } /** * 初始化 */ private void init() { mScroller = new Scroller(getContext()); lpp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); // 獲取屏幕信息 DisplayMetrics displayMetrics = new DisplayMetrics(); ((Activity) getContext()).getWindowManager().getDefaultDisplay() .getMetrics(displayMetrics); // 屏幕高度 screenHeight = displayMetrics.heightPixels; // 屏幕寬度 screenWidth = displayMetrics.widthPixels; } /** * 創建滾軸 */ private void makePaintScroll() { // 如果已經存在,則不再創建 if (null != mPaintScrollImageView || null != mPaintScrollTextView) { return; } // 創建滾軸 mPaintScrollImageView = new ImageView(getContext()); LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); lp.height = mPaintIvHeight; mPaintScrollImageView.setLayoutParams(lp); mPaintScrollImageView.setScaleType(ImageView.ScaleType.FIT_XY); mPaintScrollImageView.setImageBitmap(null == mPaintScrollBp ? makeDefaultScroll() : mPaintScrollBp); addView(mPaintScrollImageView); // 創建文字 mPaintScrollTextView = new TextView(getContext()); LayoutParams lpt = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); lpt.height = mPaintIvHeight; mPaintScrollTextView.setLayoutParams(lpt); mPaintScrollTextView.setText(null == mPaintScrollTxt ? "" : mPaintScrollTxt); mPaintScrollTextView.setTextSize(mPaintScrollTxtSize); mPaintScrollTextView.setTextColor(mPaintScrollTxtColor); mPaintScrollTextView.setGravity(Gravity.CENTER); addView(mPaintScrollTextView); } /** * 測量方法 * * @param widthMeasureSpec * @param heightMeasureSpec */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (null != mPaintView && getTop() + mPaintIvHeight != mPaintView.getHeight()) { // 重新設置圖畫高度 mPaintStartHeight = getTop() + mPaintIvHeight / 2; lpp.height = mPaintStartHeight; mPaintView.setLayoutParams(lpp); } // 測量狀態欄高度 Rect frame = new Rect(); ((Activity) getContext()).getWindow().getDecorView().getWindowVisibleDisplayFrame(frame); int statusBarHeight = frame.top; // 高度為屏幕高度減去狀態欄高度和top的高度 setMeasuredDimension(screenWidth, screenHeight - getTop() - statusBarHeight); } /** * 處理View */ private void handleView() { mPaintScrollImageView.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent event) { if (null == mPaintView) { Log.e(TAG, "設置的View為空"); return true; } // 獲取點擊的XY坐標 int x = (int) event.getRawX(); int y = (int) event.getRawY(); int action = event.getAction(); switch (action) { case MotionEvent.ACTION_DOWN: { // 請求處理點擊事件 requestDisallowInterceptTouchEvent(true); isClick = true; mLastY = y; if (!mScroller.isFinished()) { // 如果上次的調用沒有執行完就取消。 mScroller.abortAnimation(); } if (null != listener) { listener.onScrollTouch(mPaintScrollTextView); } return true; } case MotionEvent.ACTION_MOVE: { // 移動的距離 int dy = y - mLastY; mLastY = y; // 滑動 scrollBy(0, -dy); // 如果是向上滑動并且是在初始位置,則不去做處理 if (getScrollY() >= 0 && dy <= 0) { lpp.height = mPaintStartHeight; mPaintView.setLayoutParams(lpp); scrollTo(0, 0); return true; } // 如果是向下滑動并且超過屏幕高度,則不去處理 if (Math.abs(getScrollY()) >= getHeight() - mPaintIvHeight && dy >= 0) { lpp.height = mPaintStartHeight + getHeight() - mPaintIvHeight; mPaintView.setLayoutParams(lpp); scrollTo(0, -(getHeight() - mPaintIvHeight)); return true; } // 滾動回調 if (null != listener) { listener.onScrollMove(mPaintScrollTextView); } // 重新設置顯示的控件高度 if (Math.abs(getScrollY()) > 0) { lpp.height = mPaintStartHeight + Math.abs(getScrollY()); mPaintView.setLayoutParams(lpp); } return true; } case MotionEvent.ACTION_UP: // 恢復事件處理 requestDisallowInterceptTouchEvent(false); isClick = false; // 沒有發生移動 if (getScrollY() >= 0) { if (null != listener) { listener.onScrollTop(mPaintScrollTextView); } return true; } if (-getScrollY() < partitionNode) { // 如果小于臨界值,則返回起始坐標 // XY都從滑動的距離回去，最后一個參數是多少毫秒內執行完這個動作。 isScrllerTop = true; mScroller.startScroll(getScrollX(), getScrollY(), -getScrollX(), -getScrollY(), mScrollSpeed); } else { // 如果大于臨界值,則展開 isScrllerTop = false; mScroller.startScroll(getScrollX(), getScrollY(), -getScrollX(), -(getHeight() - (-getScrollY()) - mPaintIvHeight), mScrollSpeed); } invalidate(); return true; } return false; } }); } /** * 滑動處理 */ @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { // 計算新位置，并判斷上一個滾動是否完成。 // 請求處理點擊事件,防止父控件滑動 requestDisallowInterceptTouchEvent(true); scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); // 重新設置顯示的控件高度 if (0 < Math.abs(mScroller.getCurrY())) { if (!isScrllerTop) { lpp.height = mPaintStartHeight + Math.abs(mScroller.getCurrY()) + mPaintIvHeight / 2; } else { lpp.height = mPaintStartHeight + Math.abs(mScroller.getCurrY()) - mPaintIvHeight / 2; } } else { lpp.height = mPaintStartHeight; } mPaintView.setLayoutParams(lpp); invalidate(); } else { // 重新設置畫圖高度,防止高度異常 if (mPaintView.getHeight() > mPaintStartHeight + Math.abs(mScroller.getCurrY()) && !isScrllerTop && mScroller.getStartY() > 0) { lpp.height = mPaintStartHeight + Math.abs(mScroller.getCurrY()); mPaintView.setLayoutParams(lpp); } } // 防止多次調用 if (lastScrollY != mScroller.getCurrY()) { // 收縮完成 if (mScroller.getCurrY() >= 0 && !isClick) { if (null != listener) { listener.onScrollTop(mPaintScrollTextView); } } // 展開完成 if (-mScroller.getCurrY() >= getHeight() - mPaintIvHeight && !isClick) { if (null != listener) { listener.onScrollBottom(mPaintScrollTextView); } } lastScrollY = mScroller.getCurrY(); } } /** * 重置滾動 */ public void replaceScroll() { // 重置信息 scrollTo(0, 0); mScroller.setFinalY(0); lastScrollY = 0; lpp.height = mPaintStartHeight; mPaintView.setLayoutParams(lpp); if (null != listener) { listener.onScrollTop(mPaintScrollTextView); } } /** * drawable轉bitmap * * @param drawable * @return */ private Bitmap drawableToBitamp(Drawable drawable) { if (null == drawable) { return null; } if (drawable instanceof BitmapDrawable) { BitmapDrawable bd = (BitmapDrawable) drawable; return bd.getBitmap(); } int w = drawable.getIntrinsicWidth(); int h = drawable.getIntrinsicHeight(); Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); drawable.setBounds(0, 0, w, h); drawable.draw(canvas); return bitmap; } /** * 按照屏幕寬高縮放圖片 * * @param bp * @return */ private Bitmap scaleBitmal(Bitmap bp) { // 寬度比例 float scaleW = (float) screenWidth / (float) bp.getWidth(); // 高度比例 float scaleH = (float) screenHeight / (float) bp.getHeight(); // 矩陣,用于縮放圖片 Matrix matrix = new Matrix(); matrix.postScale(scaleW, scaleH); // 縮放后的圖片 Bitmap scaleBp = Bitmap.createBitmap(bp, 0, 0, bp.getWidth(), bp.getHeight(), matrix, true); return scaleBp; } /** * 設置默認的滾軸 * * @return */ private Bitmap makeDefaultScroll() { Bitmap defaultBp = Bitmap.createBitmap(screenWidth, mPaintIvHeight, Bitmap.Config.ARGB_8888); //填充顏色 defaultBp.eraseColor(Color.parseColor("#FF0000")); return defaultBp; } /** * 將px值轉換為sp值，保證文字大小不變 */ public int px2sp(float pxValue) { final float fontScale = getContext().getResources().getDisplayMetrics().scaledDensity; return (int) (pxValue / fontScale + 0.5f); }}activity_main:
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#eeeeee" tools:context="com.example.junweiliu.scrollpaintdemo.MainActivity"> <ScrollView android:layout_width="match_parent" android:layout_height="match_parent"> <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent"> <!--頭部圖片部分--> <ImageView android:id="@+id/iv_banner" android:layout_width="match_parent" android:layout_height="200dp" android:scaleType="fitXY" android:src="@mipmap/show_banner"/> <!--中間內容部分--> <LinearLayout android:id="@+id/ll_first" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/iv_banner" android:layout_marginTop="20dp" android:orientation="horizontal" android:padding="16dp"> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_a"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="藝術片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_b"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="懷舊片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_c"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="科幻片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_d"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="動畫片" android:textColor="#666666"/> </LinearLayout> </LinearLayout> <LinearLayout android:id="@+id/ll_sencond" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/ll_first" android:layout_marginTop="20dp" android:orientation="horizontal" android:padding="16dp"> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_a"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="藝術片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_b"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="懷舊片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_c"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="科幻片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_d"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="動畫片" android:textColor="#666666"/> </LinearLayout> </LinearLayout> <LinearLayout android:id="@+id/ll_threeth" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/ll_sencond" android:layout_marginTop="20dp" android:orientation="horizontal" android:padding="16dp"> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_a"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="藝術片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_b"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="懷舊片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_c"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="科幻片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_d"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="動畫片" android:textColor="#666666"/> </LinearLayout> </LinearLayout> <LinearLayout android:id="@+id/ll_fourth" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/ll_threeth" android:layout_marginTop="20dp" android:orientation="horizontal" android:padding="16dp"> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_a"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="藝術片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_b"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="懷舊片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginRight="16dp" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_c"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="科幻片" android:textColor="#666666"/> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1" android:gravity="center_horizontal" android:orientation="vertical"> <ImageView android:layout_width="80dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@mipmap/movie_playbill_d"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:gravity="center" android:text="動畫片" android:textColor="#666666"/> </LinearLayout> </LinearLayout> <!--需要顯示的圖--> <ImageView android:id="@+id/iv_paint" android:layout_width="match_parent" android:layout_height="match_parent" android:scaleType="matrix" android:src="@mipmap/show_img" android:visibility="gone"/> <!--畫軸控件--> <com.example.junweiliu.scrollpaintdemo.widget.ScrollPaintView android:id="@+id/spv_paint" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@+id/iv_banner" app:paintScrollHeight="25dp" app:paintScrollSrc="@mipmap/paint_scroll_img" app:paintScrollTxt="拉我看看" app:paintScrollTxtColor="#FF000000" app:paintScrollTxtSize="16sp" > </com.example.junweiliu.scrollpaintdemo.widget.ScrollPaintView> </RelativeLayout> </ScrollView></RelativeLayout>
attr:
<?xml version="1.0" encoding="utf-8"?><resources> <!--畫軸的高度--> <attr name="paintScrollHeight" format="dimension"/> <!--畫軸的圖片--> <attr name="paintScrollSrc" format="reference"/> <!--畫軸文字--> <attr name="paintScrollTxt" format="string"/> <!--畫軸文字顏色--> <attr name="paintScrollTxtColor" format="color"/> <!--畫軸文字大小--> <attr name="paintScrollTxtSize" format="dimension"/> <!--滾動速度--> <attr name="scrollSpeed" format="integer"/> <!--分割節點--> <attr name="scrollPartitionNode" format="integer"/> <declare-styleable name="ScrollPaintView"> <attr name="paintScrollHeight"/> <attr name="paintScrollSrc"/> <attr name="paintScrollTxt"/> <attr name="paintScrollTxtColor"/> <attr name="paintScrollTxtSize"/> <attr name="scrollSpeed"/> <attr name="scrollPartitionNode"/> </declare-styleable></resources>
四、問題
滾動的時間不宜設置太短,因為動態設置ImageView高度時可能出現繪制速度趕不上滾動的速度,會出現錯位,當然時間設置太短,也看不到這種滑動的效果了.暫時想到的做法就是這樣,應該還會有更好的方法.
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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