Android中实现记事本动态添加行效果

  this.paint = new Paint();
  paint.setStyle(Paint.Style.STROKE);
  paint.setColor(getResources().getColor(R.color.paper_line));
  paint.setStrokeWidth(getLineHeight() / 10);
  paint.setStrokeCap(Paint.Cap.ROUND);

 float startX = getPaddingLeft();//开始位置
  float stopX = getWidth() - getPaddingRight();//结束位置
  float offsetY = getPaddingTop() - getPaint().getFontMetrics().top + paint.getStrokeWidth() * 2;//行间距
  for (int i = 0; i < getLineCount(); ++i) {
   float y = offsetY + getLineHeight() * i;
   canvas.drawLine(startX, y, stopX, y, paint);
  }

/**
 * Created by dong.he on 2017/4/20 0020.
 */

public class LinedEditText extends EditText {

 Paint paint;

 public LinedEditText(Context context) {
  super(context);
  init();
 }

 public LinedEditText(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }

 public LinedEditText(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  init();
 }

 @Override
 protected void onDraw(Canvas canvas) {
  float startX = getPaddingLeft();//开始位置
  float stopX = getWidth() - getPaddingRight();//结束位置
  float offsetY = getPaddingTop() - getPaint().getFontMetrics().top + paint.getStrokeWidth() * 2;//行间距
  for (int i = 0; i < getLineCount(); ++i) {
   float y = offsetY + getLineHeight() * i;
   canvas.drawLine(startX, y, stopX, y, paint);
  }

  super.onDraw(canvas);
 }

 private void init() {
  this.paint = new Paint();
  paint.setStyle(Paint.Style.STROKE);
  paint.setColor(getResources().getColor(R.color.paper_line));
  paint.setStrokeWidth(getLineHeight() / 10);
  paint.setStrokeCap(Paint.Cap.ROUND);
 }
}

 <com.example.donghe.myview.view.LinedEditText
  android:id="@+id/textview"
  android:text="啊发发十分啊发发十分大发放大发放"
  android:textSize="18sp"
  android:background="@null"
  android:layout_width="match_parent"
  android:layout_height="wrap_content" />