效果图展示，图片有点卡，耐心看会，原程序是很流畅的
(资料图)
实现步骤：
声明变量 初始化画笔、文本大小和坐标 onMeasure()适配wrap_content的宽高 onDraw()画出根据坐标画出两段Text 监听点击事件 在Activity中实现点击事件实现原理（坐标变换原理）：整个过程都是基于坐标Y的增加和交换进行处理的，Y值都会一直增加到endY，然后进行交换逻辑
步骤一：声明变量
由于1号店是两句话的滚动，所以我们也是使用两句话来实现的
private Paint mPaint;private float x, startY, endY, firstY, nextStartY, secondY;//整个View的宽高是以第一个为标准的，所以第二句话长度必须小于第一句话private String[] text = {"今日特卖：毛衣3.3折>>>", "公告：全场半价>>>"};private float textWidth, textHeight;//滚动速度private float speech = 0;private static final int CHANGE_SPEECH = 0x01;//是否已经在滚动private boolean isScroll = false;步骤二：初始化画笔、文本大小和坐标
以第一句话为标准来做控件的宽高标准
//初始化画笔mPaint = new Paint();mPaint.setColor(Color.RED);mPaint.setTextSize(30);//测量文字的宽高，以第一句话为标准Rect rect = new Rect();mPaint.getTextBounds(text[0], 0, text[0].length(), rect);textWidth = rect.width();textHeight = rect.height();//文字开始的x,y坐标//由于文字是以基准线为基线的，文字底部会突出一点，所以向上收5pxx = getX() + getPaddingLeft();startY = getTop() + textHeight + getPaddingTop() - 5;//文字结束的x,y坐标endY = startY + textHeight + getPaddingBottom();//下一个文字滚动开始的y坐标//由于文字是以基准线为基线的，文字底部会突出一点，所以向上收5pxnextStartY = getTop() - 5;//记录开始的坐标firstY = startY;secondY = nextStartY;
步骤三：onMeasure()适配wrap_content的宽高
如果学习过自定义View的话，下面的代码应该很熟悉，就是适配warp_content的模板代码：
@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int width = measureWidth(widthMeasureSpec); int height = measureHeight(heightMeasureSpec); setMeasuredDimension(width, height);}private int measureHeight(int heightMeasureSpec) { int result = 0; int size = MeasureSpec.getSize(heightMeasureSpec); int mode = MeasureSpec.getMode(heightMeasureSpec); if (mode == MeasureSpec.EXACTLY) { result = size; } else { result = (int) (getPaddingTop() + getPaddingBottom() + textHeight); if (mode == MeasureSpec.AT_MOST) { result = Math.min(result, size); } } return result;}private int measureWidth(int widthMeasureSpec) { int result = 0; int size = MeasureSpec.getSize(widthMeasureSpec); int mode = MeasureSpec.getMode(widthMeasureSpec); if (mode == MeasureSpec.EXACTLY) { result = size; } else { result = (int) (getPaddingLeft() + getPaddingRight() + textWidth); if (mode == MeasureSpec.AT_MOST) { result = Math.min(result, size); } } return result;}步骤四：onDraw()画出根据坐标画出两段Text（已修复：Text停下来时闪一下的bug）
通过Handler来改变速度
通过isScroll锁，来控制Handler只改变一次
通过invalidate一直重绘两句话的文字
@Overrideprotected void onDraw(Canvas canvas) { super.onDraw(canvas); //启动滚动 if (!isScroll) { mHandler.sendEmptyMessageDelayed(CHANGE_SPEECH, 2000); isScroll = true; } canvas.drawText(text[0], x, startY, mPaint); canvas.drawText(text[1], x, nextStartY, mPaint); startY += speech; nextStartY += speech; //超出View的控件时 if (startY > endY || nextStartY > endY) { if (startY > endY) { //第一次滚动过后交换值 startY = secondY; nextStartY = firstY; } else if (nextStartY > endY) { //第二次滚动过后交换值 startY = firstY; nextStartY = secondY; } speech = 0; isScroll = false; } invalidate();}private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); switch (msg.what) { case CHANGE_SPEECH: speech = 1f; break; } }};步骤五：监听点击事件（已修复：点击事件错乱的问题）
在自定义View重写dispatchTouchEvent处理点击事件，这个也是模板代码：
public onTouchListener listener;public interface onTouchListener { void touchListener(String s);}public void setListener(onTouchListener listener) { this.listener = listener;}@Overridepublic boolean dispatchTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: case MotionEvent.ACTION_MOVE: //点击事件 if (listener != null) { if (startY >= firstY && nextStartY < firstY) { listener.touchListener(text[0]); } else if (nextStartY >= firstY && startY < firstY) { listener.touchListener(text[1]); } } break; } return true;}步骤六：在Activity中实现点击事件
public class VerTextViewActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_ver_text_view); VerTextView tv_ver = (VerTextView) findViewById(R.id.tv_ver); tv_ver.setListener(new VerTextView.onTouchListener() { @Override public void touchListener(String s) { Toast.makeText(VerTextViewActivity.this, s, Toast.LENGTH_LONG).show(); } }); }}布局文件
<?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"> <ImageView android:layout_width="120dp" android:layout_height="30dp" android:background="@drawable/vertextview" /> <com.handsome.app3.Custom.VerTextView.VerTextView android:id="@+id/tv_ver" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#ffffff" android:padding="8dp" /></LinearLayout>
整个类的源码：
/** * =====作者===== * 许英俊 * =====时间===== * 2016/10/11. */public class VerTextView extends View { private Paint mPaint; private float x, startY, endY, firstY, nextStartY, secondY; //整个View的宽高是以第一个为标准的，所以第二句话长度必须小于第一句话 private String[] text = {"今日特卖：毛衣3.3折>>>", "公告：全场半价>>>"}; private float textWidth, textHeight; //滚动速度 private float speech = 0; private static final int CHANGE_SPEECH = 0x01; //是否已经在滚动 private boolean isScroll = false; private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); switch (msg.what) { case CHANGE_SPEECH: speech = 1f; break; } } }; public VerTextView(Context context, AttributeSet attrs) { super(context, attrs); //初始化画笔 mPaint = new Paint(); mPaint.setColor(Color.RED); mPaint.setTextSize(30); //测量文字的宽高，以第一句话为标准 Rect rect = new Rect(); mPaint.getTextBounds(text[0], 0, text[0].length(), rect); textWidth = rect.width(); textHeight = rect.height(); //文字开始的x,y坐标 //由于文字是以基准线为基线的，文字底部会突出一点，所以向上收5px x = getX() + getPaddingLeft(); startY = getTop() + textHeight + getPaddingTop() - 5; //文字结束的x,y坐标 endY = startY + textHeight + getPaddingBottom(); //下一个文字滚动开始的y坐标 //由于文字是以基准线为基线的，文字底部会突出一点，所以向上收5px nextStartY = getTop() - 5; //记录开始的坐标 firstY = startY; secondY = nextStartY; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int width = measureWidth(widthMeasureSpec); int height = measureHeight(heightMeasureSpec); setMeasuredDimension(width, height); } private int measureHeight(int heightMeasureSpec) { int result = 0; int size = MeasureSpec.getSize(heightMeasureSpec); int mode = MeasureSpec.getMode(heightMeasureSpec); if (mode == MeasureSpec.EXACTLY) { result = size; } else { result = (int) (getPaddingTop() + getPaddingBottom() + textHeight); if (mode == MeasureSpec.AT_MOST) { result = Math.min(result, size); } } return result; } private int measureWidth(int widthMeasureSpec) { int result = 0; int size = MeasureSpec.getSize(widthMeasureSpec); int mode = MeasureSpec.getMode(widthMeasureSpec); if (mode == MeasureSpec.EXACTLY) { result = size; } else { result = (int) (getPaddingLeft() + getPaddingRight() + textWidth); if (mode == MeasureSpec.AT_MOST) { result = Math.min(result, size); } } return result; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //启动滚动 if (!isScroll) { mHandler.sendEmptyMessageDelayed(CHANGE_SPEECH, 2000); isScroll = true; } canvas.drawText(text[0], x, startY, mPaint); canvas.drawText(text[1], x, nextStartY, mPaint); startY += speech; nextStartY += speech; //超出View的控件时 if (startY > endY || nextStartY > endY) { if (startY > endY) { //第一次滚动过后交换值 startY = secondY; nextStartY = firstY; } else if (nextStartY > endY) { //第二次滚动过后交换值 startY = firstY; nextStartY = secondY; } speech = 0; isScroll = false; } invalidate(); } public onTouchListener listener; public interface onTouchListener { void touchListener(String s); } public void setListener(onTouchListener listener) { this.listener = listener; } @Override public boolean dispatchTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: case MotionEvent.ACTION_MOVE: //点击事件 if (listener != null) { if (startY >= firstY && nextStartY < firstY) { listener.touchListener(text[0]); } else if (nextStartY >= firstY && startY < firstY) { listener.touchListener(text[1]); } } break; } return true; }}以上所述是小编给大家介绍的Android自定义View实现仿1号店垂直滚动广告条代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
关键词： android滚动广告条 android 自定义view
