【Android】自定义EditText

在有些时候，我们需要一些特殊的控件，比如EditText要具有整行下划线。我们通过重写EditText来实现

public class CustomTextView extends EditText {

    private final Paint mPaint = new Paint();

    private final Rect mRect = new Rect();


    public CustomTextView(Context context) {
        super(context);
        initPaint();
    }

    public CustomTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initPaint();
    }

    public CustomTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initPaint();
    }

    public CustomTextView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        initPaint();
    }

    // 初始化画笔
    private void initPaint() {
        mPaint.setColor(Color.parseColor("#DCDCDC"));
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setAntiAlias(true);
        mPaint.setStrokeWidth(2);
    }

    @Override
    protected void onDraw(Canvas canvas) {

        Rect r = mRect;

        Paint paint = mPaint;

        // 遍历每一行文本
        for (int i = 0; i < getLineCount(); i++) {
            // 获取第i行的基线位置
            int baseline = getLineBounds(i, r);
            // 在第i行的基线上方绘制一条水平线
            canvas.drawLine(r.left, baseline + 1, r.right, baseline + 1, paint);

        }

        super.onDraw(canvas);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="class_0427.Class0427ActivityMainActivity">

    <class_0427.CustomTextView
        android:id="@+id/my_custom_textview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textSize="18sp"
        android:textColor="@color/black"
        />

</LinearLayout>

public class Class0427ActivityMainActivity extends AppCompatActivity {

    private CustomTextView my_custom_textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.class_0427_activity_main);

        my_custom_textView = findViewById(R.id.my_custom_textview);
        my_custom_textView.setText("据了解，这次演讲的主题是关于小米食堂的爆品大麻花，邴佳宝以工程师的思维去创新菜品，使得原本普通的食材焕发出了新的生机。在演讲中，他提到了“初期产能不足限量发售”、“被质疑饥饿营销”、“技术革新提高产能”等一系列充满小米特色的“米式”金句，让在场的观众都忍不住捧腹大笑，氛围比某些手机发布会还好。\n" +
                "\n" +
                "作者：王五\n" +
                "链接：https://www.zhihu.com/question\n" +
                "来源：知乎\n" +
                "著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。");
    }
}