效果圖展示，圖片有點卡，耐心看會，原程序是很流暢的
實現步驟：
實現原理（坐標變換原理）：整個過程都是基于坐標Y的增加和交換進行處理的，Y值都會一直增加到endY，然后進行交換邏輯
步驟一：聲明變量
由于1號店是兩句話的滾動，所以我們也是使用兩句話來實現的
private Paint mPaint;private float x, startY, endY, firstY, nextStartY, secondY;//整個View的寬高是以第一個為標準的，所以第二句話長度必須小于第一句話private String[] text = {"今日特賣：毛衣3.3折>>>", "公告：全場半價>>>"};private float textWidth, textHeight;//滾動速度private float speech = 0;private static final int CHANGE_SPEECH = 0x01;//是否已經在滾動private boolean isScroll = false;步驟二：初始化畫筆、文本大小和坐標
以第一句話為標準來做控件的寬高標準
//初始化畫筆mPaint = new Paint();mPaint.setColor(Color.RED);mPaint.setTextSize(30);//測量文字的寬高，以第一句話為標準Rect rect = new Rect();mPaint.getTextBounds(text[0], 0, text[0].length(), rect);textWidth = rect.width();textHeight = rect.height();//文字開始的x,y坐標//由于文字是以基準線為基線的，文字底部會突出一點，所以向上收5pxx = getX() + getPaddingLeft();startY = getTop() + textHeight + getPaddingTop() - 5;//文字結束的x,y坐標endY = startY + textHeight + getPaddingBottom();//下一個文字滾動開始的y坐標//由于文字是以基準線為基線的，文字底部會突出一點，所以向上收5pxnextStartY = getTop() - 5;//記錄開始的坐標firstY = startY;secondY = nextStartY;
步驟三：onMeasure()適配wrap_content的寬高
如果學習過自定義View的話，下面的代碼應該很熟悉，就是適配warp_content的模板代碼：
@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;}步驟四：onDraw()畫出根據坐標畫出兩段Text（已修復：Text停下來時閃一下的bug）
通過Handler來改變速度
通過isScroll鎖，來控制Handler只改變一次
通過invalidate一直重繪兩句話的文字
@Overrideprotected void onDraw(Canvas canvas) { super.onDraw(canvas); //啟動滾動 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的控件時 if (startY > endY || nextStartY > endY) { if (startY > endY) { //第一次滾動過后交換值 startY = secondY; nextStartY = firstY; } else if (nextStartY > endY) { //第二次滾動過后交換值 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; } }};步驟五：監聽點擊事件（已修復：點擊事件錯亂的問題）
在自定義View重寫dispatchTouchEvent處理點擊事件，這個也是模板代碼：
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: //點擊事件 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;}步驟六：在Activity中實現點擊事件
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>
整個類的源碼：
/** * =====作者===== * 許英俊 * =====時間===== * 2016/10/11. */public class VerTextView extends View { private Paint mPaint; private float x, startY, endY, firstY, nextStartY, secondY; //整個View的寬高是以第一個為標準的，所以第二句話長度必須小于第一句話 private String[] text = {"今日特賣：毛衣3.3折>>>", "公告：全場半價>>>"}; private float textWidth, textHeight; //滾動速度 private float speech = 0; private static final int CHANGE_SPEECH = 0x01; //是否已經在滾動 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); //初始化畫筆 mPaint = new Paint(); mPaint.setColor(Color.RED); mPaint.setTextSize(30); //測量文字的寬高，以第一句話為標準 Rect rect = new Rect(); mPaint.getTextBounds(text[0], 0, text[0].length(), rect); textWidth = rect.width(); textHeight = rect.height(); //文字開始的x,y坐標 //由于文字是以基準線為基線的，文字底部會突出一點，所以向上收5px x = getX() + getPaddingLeft(); startY = getTop() + textHeight + getPaddingTop() - 5; //文字結束的x,y坐標 endY = startY + textHeight + getPaddingBottom(); //下一個文字滾動開始的y坐標 //由于文字是以基準線為基線的，文字底部會突出一點，所以向上收5px nextStartY = getTop() - 5; //記錄開始的坐標 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); //啟動滾動 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的控件時 if (startY > endY || nextStartY > endY) { if (startY > endY) { //第一次滾動過后交換值 startY = secondY; nextStartY = firstY; } else if (nextStartY > endY) { //第二次滾動過后交換值 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: //點擊事件 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; }}以上所述是小編給大家介紹的Android自定義View實現仿1號店垂直滾動廣告條代碼，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對武林網網站的支持！
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