Android realizes the scrolling effect of lyrics

In this paper, we share the specific code of Android to realize the scrolling effect of lyrics for your reference. The specific contents are as follows

Custom TextView

public class VerticalScrollTextView extends TextView {
 private Paint mPaint;
 private float mX;
 private Paint mPathPaint; 
 public int index = 0;
 private List<Sentence> list;
 public float mTouchHistoryY;
 private int mY; 
 private float middleY;//
 private static final int DY = 40; //
 public VerticalScrollTextView(Context context) {
 super(context);
 init();
 }
 public VerticalScrollTextView(Context context, AttributeSet attr) {
 super(context, attr);
 init();
 }
 public VerticalScrollTextView(Context context, AttributeSet attr, int i) {
 super(context, attr, i);
 init();
 }
 private void init() {
 setFocusable(true);
 if(list==null){
  list=new ArrayList<Sentence>();
  Sentence sen=new Sentence(0," ");
  list.add(0, sen);
 } 

 // 
 mPaint = new Paint();
 mPaint.setAntiAlias(true);
 mPaint.setTextSize(24);
 mPaint.setColor(Color.BLACK);
 mPaint.setAlpha(80);
 mPaint.setTypeface(Typeface.SERIF);

 // 
 mPathPaint = new Paint();
 mPathPaint.setAntiAlias(true);
 mPathPaint.setColor(Color.RED);
 mPathPaint.setTextSize(24);
 mPathPaint.setTypeface(Typeface.SANS_SERIF);
 }
 protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);
 canvas.drawColor(0xEFeffff);
 Paint p = mPaint;
 Paint p2 = mPathPaint;
 p.setTextAlign(Paint.Align.LEFT);
 if (index == -1)
  return;
 p2.setTextAlign(Paint.Align.LEFT);
 // 
 canvas.drawText(list.get(index).getName(), mX, middleY, p2);
 float tempY = middleY;
 // 
 for (int i = index - 1; i >= 0; i--) {  
  tempY = tempY - DY;
  if (tempY < 0) {
  break;
  }
  canvas.drawText(list.get(i).getName(), mX, tempY, p);  
 }
 tempY = middleY;
 //
 for (int i = index + 1; i < list.size(); i++) {
  // 
  tempY = tempY + DY;
  if (tempY > mY) {
  break;
  }
  canvas.drawText(list.get(i).getName(), mX, tempY, p);  
 }
 }
 protected void onSizeChanged(int w, int h, int ow, int oh) {
 super.onSizeChanged(w, h, ow, oh);
 mX = w * 0.3f; 
 mY = h;
 middleY = h * 0.5f;
 }

 public long updateIndex(int index) { 
 if (index == -1)
  return -1;
 this.index=index; 
 return index;
 }

 public List<Sentence> getList() {
 return list;
 }

 public void setList(List<Sentence> list) {
 this.list = list;
 }
 public void updateUI(){
 new Thread(new updateThread()).start();
 }
 class updateThread implements Runnable {
 long time = 300; 
 int i=0;
 public void run() {
  while (true) {
  long sleeptime = updateIndex(i);
  time += sleeptime;
  mHandler.post(mUpdateResults);
  if (sleeptime == -1)
   return;
  try {
   Thread.sleep(time);
   i++;
   if(i==getList().size())
   {
    i=0;
    time = 300;
   }
  } catch (InterruptedException e) {   
   e.printStackTrace();
  }
  }
 }
 }
 Handler mHandler = new Handler();
 Runnable mUpdateResults = new Runnable() {
 public void run() {
  invalidate(); // 
 }
 };
}

Data encapsulation class

public class Sentence {

 private String name;
 private int index;

 public Sentence(int index,String name){
 this.name=name;
 this.index=index;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public int getIndex() {
 return index;
 }

 public void setIndex(int index) {
 this.index = index;
 }


}

Layout

<com.mypackager.ui.VerticalScrollTextView
  android:id="@+id/scoll_textView"
  android:layout_width="500dp"
  android:layout_height="500dp"
  android:text="@string/company_intrduce_text"
  android:visibility="gone"
  ></com.mypackager.VerticalScrollTextView>

Activity code

List lst=new ArrayList<Sentence>();
  for(int i=0;i<8;i++){
  if(i%2==0){
   Sentence sen=new Sentence(i,i+1+"NanJINGXIXI");
   lst.add(i, sen);
  }else{
   Sentence sen=new Sentence(i,i+1+"Hello world!");
   lst.add(i, sen);
  }
  } 

  play_textView.setList(lst);

  play_textView.updateUI();