Android 重写EditText自定义密码输入框

首先看看效果

如上图的密码输入框，没有密码时，有几个密码就有几条下划线，输入密码后显示的内容为“*”，并且底部就没有下划线了，同样有很多方式实现，这里就偷懒改改EditText来实现，所以需要做的就是画线、画“*”，代码很简单，偷懒也没有写attr，属性直接初始化写死了。这个思路同样适用于那些内容区域是方框的密码输入，就是画线和画矩形的区别。

1public class PasswordUnderLineEditText extends EditText {
2
3    public interface TextIndexChangeListener {
4        void onTextIndexChange(CharSequence text, int index);
5    }
6
7    private TextIndexChangeListener mTextIndexChangeListener;
8
9    @ColorInt
10    private int lineColor;
11    private int lineCount;
12    private int lineMargin;
13    private int lineHeight;
14    private int linePaddingBottom;
15
16    private String changedText;
17    private int changedTextSize;
18    private int changedTextColor;
19    private int textLength;
20    private boolean isHideLineOnChanged;
21
22    private Paint mLinePaint;
23    private TextPaint mChangedTextPaint;
24
25
26    public PasswordUnderLineEditText(Context context) {
27        this(context, null);
28    }
29
30    public PasswordUnderLineEditText(Context context, AttributeSet attrs) {
31        super(context, attrs);
32        lineColor = getResources().getColor(R.color.gray);
33        changedTextColor = getResources().getColor(R.color.black);
34        lineCount = 6;
35        changedTextSize = DensityUtil.sp2px(context, 20);
36        lineMargin = DensityUtil.dp2px(context, 12);
37        linePaddingBottom = DensityUtil.dp2px(context, 10);
38        lineHeight = DensityUtil.dp2px(context, 1);
39
40        changedText = "*";
41        isHideLineOnChanged = true;
42        setGravity(Gravity.CENTER_VERTICAL);
43        setTextColor(getResources().getColor(android.R.color.transparent));
44        setBackgroundColor(Color.WHITE);
45        setCursorVisible(false); 
46        setInputType(InputType.TYPE_CLASS_NUMBER); 
47        setFilters(new InputFilter[]{new InputFilter.LengthFilter(lineCount)});
48
49        mLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
50        mLinePaint.setColor(lineColor);
51        mLinePaint.setStyle(Paint.Style.FILL);
52        mLinePaint.setStrokeWidth(lineHeight);
53        mChangedTextPaint = new TextPaint();
54        mChangedTextPaint.setColor(changedTextColor);
55        mChangedTextPaint.setTextSize(changedTextSize);
56        mChangedTextPaint.setStyle(Paint.Style.FILL);
57    }
58
59    @Override
60    protected void onDraw(Canvas canvas) {
61        super.onDraw(canvas);
62        int height = getHeight();
63        int width = getWidth();
64        canvas.save();
65
66        int singleLineWidth = width / lineCount;
67        int startX = 0;
68        int stopX = 0;
69        int startY = height - linePaddingBottom;
70        for (int i = 0; i < lineCount; i++) {
71            if (textLength == 0) {
72                startX = i * singleLineWidth + lineMargin;
73                stopX = (i + 1) * singleLineWidth - lineMargin;
74                canvas.drawLine(startX, startY, stopX, startY, mLinePaint);
75            } else if (textLength > 0) {
76                int changeIndex;
77                if (isHideLineOnChanged) {
78                    changeIndex = textLength;
79                } else {
80                    changeIndex = 0;
81                }
82                startX = (i + changeIndex) * singleLineWidth + lineMargin;
83                stopX = (i + changeIndex + 1) * singleLineWidth - lineMargin;
84                canvas.drawLine(startX, startY, stopX, startY, mLinePaint);
85            }
86        }
87        for (int i = 0; i < textLength; i++) {
88            startX = i * singleLineWidth + lineMargin;
89            stopX = (i + 1) * singleLineWidth - lineMargin;
90            canvas.drawText(changedText, (startX + stopX) / 2 - changedTextSize / 4, (height + changedTextSize) / 2, mChangedTextPaint);
91        }
92
93        canvas.restore();
94    }
95
96
97    @Override
98    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
99        this.textLength = text.length();
100        invalidate();
101        if(mTextIndexChangeListener!=null){
102            mTextIndexChangeListener.onTextIndexChange(text,textLength);
103        }
104    }