ViewGroup可实现上下、各地跑马灯效果滚动-白红宇

ViewGroup可实现上下、各地跑马灯效果滚动

阅读量：5831 次

发布时间：2019-06-18

本文共 7638 字，大约阅读时间需要 25 分钟。

先上效果图：

代码：

package com.example.scrolltextview;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Paint;import android.os.Handler;import android.os.Message;import android.util.AttributeSet;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.LinearLayout;import android.widget.Scroller;import android.widget.SpinnerAdapter;import android.widget.TextView;public class ScrollTextView extends ViewGroup {	private static final int SCROLL = 0;	private static final int JUSTIFY = 1;	private static final int ANIMATION_DURATION = 3000;		private int mOrientation;	private int mSize;	private int mIndex;	private int mPosition;	private Scroller mScroller;	private Map
     
       mViews;	private SpinnerAdapter mAdapter;	private int mPackedViews;	private int mAnimationDuration;			private float measuredWidth = 0;	private float textSize = 0;	private float measuredHeight = 0;	private String text= null;	private String[] data;	private boolean flag = true;	public ScrollTextView(Context context, AttributeSet attrs) {		super(context, attrs);				int[] linerarLayoutAttrs = {			android.R.attr.orientation,		};		TypedArray a = context.obtainStyledAttributes(attrs, linerarLayoutAttrs);		mOrientation = a.getInteger(0, LinearLayout.HORIZONTAL);		a.recycle();		mAnimationDuration = ANIMATION_DURATION;		mScroller = new Scroller(context);		mIndex = -1;		mPosition = -1;		mPackedViews = -1;		mViews = new HashMap
      
       ();		setFocusable(true);		setFocusableInTouchMode(true);		}		public float getCharacterWidth(String text, float size){		if(null == text || "".equals(text))			return 0;		float width = 0;		Paint paint = new Paint();		paint.setTextSize(size);		float text_width = paint.measureText(text);//得到整体长度				width = text_width/text.length();//字符的长度		return width;	}			public void setText(String text)	{		this.text = text;		data  = new String[]{this.text};		LayoutInflater inflater= (LayoutInflater) getContext().getSystemService(getContext().LAYOUT_INFLATER_SERVICE);		TextView view = (TextView) inflater.inflate(R.layout.scroll_text_view, null);		textSize = view.getTextSize();		measuredHeight = textSize;		textSize = getCharacterWidth(text,textSize);	}		public void beginScroll()	{		thread.start();	}	Thread thread = new Thread(new Runnable() {		boolean enabled = true;		@Override		public void run() {			// TODO Auto-generated method stub			while(enabled)			{				try {					Thread.sleep(4000);				} catch (InterruptedException e) {					// TODO Auto-generated catch block					e.printStackTrace();				}				setNextView();				enabled = mIndex + 1 < mAdapter.getCount();			}		}	});		@Override	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {		super.onMeasure(widthMeasureSpec, heightMeasureSpec);		measuredWidth = getMeasuredWidth();		mSize = mOrientation == LinearLayout.HORIZONTAL?

getMeasuredWidth() : getMeasuredHeight(); if(flag && text!=null) { int length = text.length(); Log.i("AAA", "length*textSize:"+length*textSize+" measuredWidth:"+measuredWidth); if(length*textSize >= measuredWidth) { int textCountInOneLine = (int) (measuredWidth/textSize -1); int lineCount =(int) ((length%textCountInOneLine==0)? (length/textCountInOneLine):(length/textCountInOneLine+1)); Log.i("AAA", "length:"+length+" textCountInOneLine:"+textCountInOneLine+" lineCount:"+lineCount); data = new String[lineCount]; for(int i=0;i<lineCount;i++) { if((i+1)*textCountInOneLine<length) data[i] = text.substring(i*textCountInOneLine, (i+1)*textCountInOneLine); else data[i] = text.substring(i*textCountInOneLine, length); Log.i("AAA", "data:"+data[i]); } } else { data = new String[]{text}; } ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(), R.layout.scroll_text_view, data); setAdapter(adapter); flag = false; } View view = getChildAt(0); if(view!=null) { measureChild(view, widthMeasureSpec, widthMeasureSpec); measuredHeight = view.getMeasuredHeight(); } setMeasuredDimension((int)measuredWidth, (int)measuredHeight); } private int getPackedViews(int offset) { int size = mSize; int start = offset / size; int numViews = offset % size != 0?

1 : 0; return start << 1 | numViews; } Handler handler = new Handler() { @Override public void handleMessage(Message msg) { mScroller.computeScrollOffset(); int currX = mScroller.getCurrX(); int delta = mPosition - currX; mPosition = currX; int packed = getPackedViews(mPosition); manageViews(packed); scroll(delta); if (!mScroller.isFinished()) { handler.sendEmptyMessage(msg.what); } else { if (msg.what == SCROLL) { justify(); } else { mIndex = mPosition / mSize; } } } }; private void justify() { int offset = mPosition % mSize; if (offset != 0) { int endPosition = mPosition - offset; if (offset > mSize / 2) { endPosition += mSize; } mScroller.startScroll(mPosition, 0, endPosition - mPosition, 0, mAnimationDuration); handler.sendEmptyMessage(JUSTIFY); } else { mIndex = mPosition / mSize; } } private void scroll(int offset) { if (mOrientation == LinearLayout.HORIZONTAL) { for (View view : mViews.keySet()) { view.offsetLeftAndRight(offset); } } else { for (View view : mViews.keySet()) { view.offsetTopAndBottom(offset); } } invalidate(); } public void setSelection(int index, boolean animate) { if (index == mIndex) { return; } int endPosition = index * mSize; int diff = Math.abs(index - mIndex); int sign = index > mIndex?

1 : -1; mIndex = index; if (diff > 1) { mPosition = endPosition - sign * mSize; } if (animate) { mScroller.startScroll(mPosition, 0, endPosition - mPosition, 0, mAnimationDuration); handler.removeMessages(JUSTIFY); handler.removeMessages(SCROLL); handler.sendEmptyMessage(JUSTIFY); } else { mPosition = endPosition; manageViews(index << 1); invalidate(); } } private void manageViews(int packedViews) { if (packedViews == mPackedViews) { return; } mPackedViews = packedViews; int startIdx = packedViews >> 1; int endIdx = startIdx + (packedViews & 1); int viewIdx = startIdx; while (viewIdx <= endIdx) { if (!mViews.containsValue(viewIdx)) { if (viewIdx >= 0 && viewIdx < mAdapter.getCount()) { View view = mAdapter.getView(viewIdx, null, this); mViews.put(view, viewIdx); addView(view); } } viewIdx++; } // remove not visible views Iterator<View> iterator = mViews.keySet().iterator(); while (iterator.hasNext()) { View view = iterator.next(); int idx = mViews.get(view); if (idx < startIdx || idx > endIdx) { iterator.remove(); removeView(view); } } } public int getSelection() { return mIndex; } public void setPreviousView() { if (mAdapter != null && mIndex > 0) { setSelection(mIndex-1, true); } } public void setNextView() { if (mAdapter != null && mIndex + 1 < mAdapter.getCount()) { setSelection(mIndex+1, true); } } public void setAdapter(SpinnerAdapter adapter) { mAdapter = adapter; if (mAdapter != null) { setSelection(0, false); } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { for (View view : mViews.keySet()) { if (view.getWidth() == 0) { // new View: not layout()ed int idx = mViews.get(view); if (mOrientation == LinearLayout.HORIZONTAL) { int left = mSize * idx - mPosition; view.layout(left, 0, left+r-l, b-t); } else { int top = mSize * idx - mPosition; view.layout(0, top, r-l, top+b-t); } } } } }

使用：

String temp = getResources().getString(R.string.info);	    ScrollTextView switcher1 = (ScrollTextView) findViewById(R.id.switcher1);		switcher1.setText(temp);		switcher1.beginScroll();

唉，我认为我真是懒....

还是直接给project吧!

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