欢迎来到“实现自定义密码输入控件”这一章节,PasswordInputView定义了密码输入的监听,支持直接在布局文件定义属性值、支持直接获取密码输入的长度、原始密码……
先上图
PasswordInputView是做什么的?
PasswordInputView是一个自定义密码输入的控件,类似支付宝、微信支付的密码输入,同时定义了密码输入的监听,支持直接在布局文件定义属性值、支持直接获取密码输入的长度、原始密码等,还可以扩展其他方法,请自行实现。
实现原理
1.创建一个类 ‘PasswordInputView' ,让其继承EditText,因为我们要实现的自定义view是用来密码输入的,所以必须继承EditText。
2.为了在布局(layout)文件(.xml)能直接定义PasswordInputView各个属性的值,我们需要定义PasswordInputView带AttributeSet 参数的构造方法。
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public PasswordInputView(Context context, AttributeSet attr) { super (context, attr); init(context, attr); } |
3.在'value/attrs.xml'中定义PasswordInputView各个属性及其类型,如:
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<? xml version = "1.0" encoding = "utf-8" ?> < resources > < declare-styleable name = "Passwordinputview" > < attr name = "passwordLength" format = "integer" /> < attr name = "borderWidth" format = "dimension" /> < attr name = "borderRadius" format = "dimension" /> < attr name = "borderColor" format = "color" /> < attr name = "passwordWidth" format = "dimension" /> < attr name = "passwordColor" format = "color" /> </ declare-styleable > </ resources > |
4.重载OnDraw(Canvas canvas)方法,并在其实现画边框、画内容区域(以填充模式绘制Paint.Style.FILL)、画分割线、画实心圆点(密码)。有人可能会问:画了边框、分割线,就可以了,为什么还要画内容区域?问得好,笔者在实现过程中也碰到这个问题,当时没有画内容区域,导致输入的原始内容也显示出来了(如下异常图),所以画内容区域(以填充模式绘制Paint.Style.FILL)是为了掩盖原始内容不被发现,切记必不可少。
正确代码如下:
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private void init(Context context, AttributeSet attr) { TypedArray ta = context.obtainStyledAttributes(attr, R.styleable.Passwordinputview); try { passwordLength = ta.getInt(R.styleable.Passwordinputview_passwordLength, passwordLength); borderWidth = ta.getDimensionPixelSize(R.styleable.Passwordinputview_borderWidth, borderWidth); borderRadius = ta.getDimensionPixelSize(R.styleable.Passwordinputview_borderRadius, borderRadius); borderColor = ta.getColor(R.styleable.Passwordinputview_borderColor, borderColor); passwordWidth = ta.getDimensionPixelSize(R.styleable.Passwordinputview_passwordWidth, passwordWidth); passwordColor = ta.getColor(R.styleable.Passwordinputview_passwordColor, passwordColor); } catch (Exception e) { } ta.recycle(); borderPaint = new Paint(); borderPaint.setAntiAlias( true ); borderPaint.setColor(borderColor); borderPaint.setStrokeWidth(borderWidth); borderPaint.setStyle(Paint.Style.FILL); //以填充模式来画,防止原始输入内容显示出来 passwordPaint = new Paint(); passwordPaint.setAntiAlias( true ); passwordPaint.setColor(passwordColor); passwordPaint.setStrokeWidth(passwordWidth); } @Override protected void onDraw(Canvas canvas) { // TODO Auto-generated method stub super .onDraw(canvas); int width = getWidth(); int height = getHeight(); //画边框 RectF rect = new RectF( 0 , 0 , width, height); borderPaint.setColor(borderColor); canvas.drawRoundRect(rect, borderRadius, borderRadius, borderPaint); //画内容区域,与上面的borderPaint.setStyle(Paint.Style.FILL)对应, 防止原始输入内容显示出来 RectF rectContent = new RectF(rect.left + defaultContentMargin, rect.top + defaultContentMargin, rect.right - defaultContentMargin, rect.bottom - defaultContentMargin); borderPaint.setColor(Color.WHITE); canvas.drawRoundRect(rectContent, borderRadius, borderRadius, borderPaint); //画分割线:分割线数量比密码数少1 borderPaint.setColor(borderColor); borderPaint.setStrokeWidth(defaultSplitLineWidth); for ( int i = 1 ; i < passwordLength; i++) { float x = width * i / passwordLength; canvas.drawLine(x, 0 , x, height, borderPaint); } //画密码内容 float px, py = height / 2 ; float halfWidth = width / passwordLength / 2 ; for ( int i = 0 ; i < textLength; i++) { px = width * i / passwordLength + halfWidth; canvas.drawCircle(px, py, passwordWidth, passwordPaint); } } |
5.定义“设置属性值”的方法,如下
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public void setBorderWidth( int borderWidth) { this .borderWidth = borderWidth; borderPaint.setStrokeWidth(borderWidth); postInvalidate(); } |
动态图
项目源码
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/weiren1101/article/details/53396222