安卓手记--No4：在安卓6上，EditText文字右对齐时光标出现在hint文字的左边

现象：
初始化的时候，光标在hint文字的右边 – OK
输入value后，光标在value的右边 – OK
删除value后，光标在hint文字的左边 – 不对

思路：
自定义封装一个EditText，命名MyEditText，继承AppCompatEditText
在初始化时拿到设置的hint保存起来，然后清空EditText本身的hint，最后在onDraw()方法中绘制自己的hint。

代码如下

import android.content.Context;
import android.content.res.ColorStateList;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.text.TextUtils;
import android.util.AttributeSet;

import androidx.appcompat.widget.AppCompatEditText;

public class MyEditText extends AppCompatEditText {

    private CharSequence mHint;
    private Paint mHintPaint;
    private int mCurHintTextColor;

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

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

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

    private void init() {
        mHint = getHint();
        setHint("");
        mHintPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
        mHintPaint.setTextSize(getTextSize());
        mHintPaint.setTextAlign(Paint.Align.RIGHT);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (TextUtils.isEmpty(mHint) || !TextUtils.isEmpty(getText())) {
            return;
        }
        canvas.save();
        ColorStateList hintTextColors = getHintTextColors();
        if (hintTextColors != null) {
            int color = hintTextColors.getColorForState(getDrawableState(), 0);
            if (color != mCurHintTextColor) {
                mCurHintTextColor = color;
                mHintPaint.setColor(color);
            }
        }

        Paint.FontMetricsInt fontMetrics = mHintPaint.getFontMetricsInt();
        int baseline = (getHeight() - fontMetrics.bottom + fontMetrics.top) / 2 - fontMetrics.top;
        canvas.drawText(mHint, 0, mHint.length(),
                getWidth() - getPaddingRight() + getScrollX(),
                baseline, mHintPaint);
        canvas.restore();
    }
}

本文地址：https://blog.csdn.net/weixin_48576311/article/details/108705196