继续练习自定义View，这次带来的圆形进度条控件与之前的圆形百分比控件大同小异，这次涉及到了渐变渲染以及画布旋转等知识点，效果如下：
虽然步骤类似，但是我还是要写，毕竟基础的东西就是要多练
1、在res/values文件夹下新建attrs.xml文件，编写自定义属性：
<?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="CircleProgressView"> <!-- 弧线宽度 --> <attr name="arcWidth" format="dimension" /> <!-- 刻度个数 --> <attr name="scaleCount" format="integer" /> <!-- 渐变起始颜色 --> <attr name="startColor" format="color" /> <!-- 渐变终止颜色 --> <attr name="endColor" format="color" /> <!-- 标签说明文本 --> <attr name="labelText" format="string" /> <!-- 文本颜色 --> <attr name="textColor" format="color" /> <!-- 百分比文本字体大小 --> <attr name="progressTextSize" format="dimension" /> <!-- 标签说明字体大小 --> <attr name="labelTextSize" format="dimension" /> </declare-styleable> </resources>
2、新建CircleProgressView继承View，重写构造方法：
public CircleProgressView(Context context) { this(context, null); } public CircleProgressView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public CircleProgressView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); }
3、在第三个构造方法中获取自定义属性的值：
TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CircleProgressView, defStyleAttr, 0); mArcWidth = ta.getDimension(R.styleable.CircleProgressView_arcWidth, DensityUtils.dp2px(context, 8)); mScaleCount = ta.getInteger(R.styleable.CircleProgressView_scaleCount, 24); mStartColor = ta.getColor(R.styleable.CircleProgressView_startColor, Color.parseColor("#3FC199")); mEndColor = ta.getColor(R.styleable.CircleProgressView_endColor, Color.parseColor("#3294C1")); mColorArray = new int[]{mStartColor, mEndColor}; mLabelText = ta.getString(R.styleable.CircleProgressView_labelText); mTextColor = ta.getColor(R.styleable.CircleProgressView_textColor, Color.parseColor("#4F5F6F")); mProgressTextSize = ta.getDimension(R.styleable.CircleProgressView_progressTextSize, 160); mLabelTextSize = ta.getDimension(R.styleable.CircleProgressView_labelTextSize, 64); ta.recycle();
4、创建画图所使用的对象，如Paint、Rect、RectF：
mArcBackPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mArcBackPaint.setStyle(Paint.Style.STROKE); mArcBackPaint.setStrokeWidth(mArcWidth); mArcBackPaint.setColor(Color.LTGRAY); mArcForePaint = new Paint(Paint.ANTI_ALIAS_FLAG); mArcForePaint.setStyle(Paint.Style.STROKE); mArcForePaint.setStrokeWidth(mArcWidth); mArcRectF = new RectF(); mLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG); mLinePaint.setStyle(Paint.Style.STROKE); mLinePaint.setColor(Color.WHITE); mLinePaint.setStrokeWidth(DensityUtils.dp2px(context, 2)); mProgressTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mProgressTextPaint.setStyle(Paint.Style.FILL); mProgressTextPaint.setColor(mTextColor); mProgressTextPaint.setTextSize(mProgressTextSize); mLabelTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mLabelTextPaint.setStyle(Paint.Style.FILL); mLabelTextPaint.setColor(mTextColor); mLabelTextPaint.setTextSize(mLabelTextSize); mTextRect = new Rect();
5、重写onMeasure()方法，计算自定义View的宽高：
@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measuredDimension(widthMeasureSpec), measuredDimension(heightMeasureSpec)); } private int measuredDimension(int measureSpec) { int result; int mode = MeasureSpec.getMode(measureSpec); int size = MeasureSpec.getSize(measureSpec); if (mode == MeasureSpec.EXACTLY) { result = size; } else { result = 800; if (mode == MeasureSpec.AT_MOST) { result = Math.min(result, size); } } return result; }
6、重写onDraw()方法，绘制圆弧、刻度线和百分比文本、标签说明文本，注意坐标的计算：
@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mArcRectF.set(mArcWidth / 2, mArcWidth / 2, getWidth() - mArcWidth / 2, getHeight() - mArcWidth / 2); //画背景弧线 canvas.drawArc(mArcRectF, -90, 360, false, mArcBackPaint); //设置渐变渲染 LinearGradient linearGradient = new LinearGradient(getWidth() / 2, 0, getWidth() / 2, getHeight(), mColorArray, null, Shader.TileMode.CLAMP); mArcForePaint.setShader(linearGradient); //画百分比值弧线 canvas.drawArc(mArcRectF, -90, mSweepAngle, false, mArcForePaint); //画刻度线 for (int i = 0; i < mScaleCount; i++) { canvas.drawLine(getWidth() / 2, 0, getWidth() / 2, mArcWidth, mLinePaint); //旋转画布 canvas.rotate(360 / mScaleCount, getWidth() / 2, getHeight() / 2); } //画百分比文本 String progressText = mProgress + "%"; mProgressTextPaint.getTextBounds(progressText, 0, progressText.length(), mTextRect); float progressTextWidth = mTextRect.width(); float progressTextHeight = mTextRect.height(); canvas.drawText(progressText, getWidth() / 2 - progressTextWidth / 2, getHeight() / 2 + progressTextHeight / 2, mProgressTextPaint); //画标签说明文本 mLabelTextPaint.getTextBounds(mLabelText, 0, mLabelText.length(), mTextRect); canvas.drawText(mLabelText, getWidth() / 2 - mTextRect.width() / 2, getHeight() / 2 - progressTextHeight / 2 - mTextRect.height(), mLabelTextPaint); }
7、暴露一个动态设置百分比的方法：
public void setProgress(float progress) { Log.e("--> ", progress + ""); ValueAnimator anim = ValueAnimator.ofFloat(mProgress, progress); anim.setDuration((long) (Math.abs(mProgress - progress) * 20)); anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { mProgress = (float) animation.getAnimatedValue(); mSweepAngle = mProgress * 360 / 100; mProgress = (float) (Math.round(mProgress * 10)) / 10;//四舍五入保留到小数点后两位 invalidate(); } }); anim.start(); }
8、在activity_main.xml布局文件中使用该View：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:cpv="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity"> <com.monkey.circleprogressview.CircleProgressView android:id="@+id/circle_progress_view" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" cpv:arcWidth="8dp" cpv:endColor="#126b94" cpv:labelText="学习进度" cpv:labelTextSize="20sp" cpv:progressTextSize="55sp" cpv:scaleCount="24" cpv:startColor="#12d699" cpv:textColor="#4F5F6F" /> </RelativeLayout>
9、在MainActivity中设置监听，传入百分比：
final CircleProgressView view = (CircleProgressView) findViewById(R.id.circle_progress_view); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { float progress = (float) (Math.random() * 100); view.setProgress(progress); } });
代码下载地址：
https://github.com/MonkeyMushroom/CircleProgressView/tree/master
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脚本之家。