<span style="font-family: Arial, Helvetica, sans-serif;"><?xml version="1.0" encoding="utf-8"?>    </span>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    
    android:layout_width="fill_parent"    
    android:layout_height="fill_parent"    
    >    
<!--注意名称 -->    
<com.marine.study.LineEditText     
        
    android:id="@+id/myEdit"    
    android:layout_width="fill_parent"     
    android:layout_height="wrap_content"     
    style="?android:attr/textViewStyle"     
    android:background="@null"    
    android:textColor="@null"     
/>    
</LinearLayout>  

其中background，可以设置成其他颜色等

textColor不一定要是null，可以设置字体颜色

加下划线

public class LineEditText extends EditText {
      // 画笔 用来画下划线
    private Paint paint;
  
      public LineEditText(Context context, AttributeSet attrs) {
          super(context, attrs);
          paint = new Paint();
          paint.setStyle(Paint.Style.STROKE);
          paint.setColor(Color.RED);
         // 开启抗锯齿 较耗内存
         paint.setAntiAlias(true);
     }
 
	   @Override
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);
         // 得到总行数
         int lineCount = getLineCount();
         // 得到每行的高度
         int lineHeight = getLineHeight();
         // 根据行数循环画线
         for (int i = 0; i < lineCount; i++) {
             int lineY = (i + 1) * lineHeight;
             canvas.drawLine(0, lineY, this.getWidth(), lineY, paint);
         }
 
     }
 
 }