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    android自定義view實現圓環效果
    2021-09-16 11:42:40

    先上規矩吧:

    android自定義view實現圓環效果_ide? ? ? ? ?android自定義view實現圓環效果_xml_02

    重要的是如何實現自定義的view效果

    (1)創建類,繼承view,重寫onDraw和onMesure方法

    public class CirclePercentBar extends View{
    
        private Context mContext;
    
        private int mArcColor;
        private int mArcWidth;
        private int mCenterTextColor;
        private int mCenterTextSize;
        private int mCircleRadius;
        private Paint arcPaint;
        private Paint arcCirclePaint;
        private Paint centerTextPaint;
        private RectF arcRectF;
        private Rect textBoundRect;
        private float mCurData=0;
        private int arcStartColor;
        private int arcEndColor;
        private Paint startCirclePaint;
    
        public CirclePercentBar(Context context) {
            this(context, null);
        }
    
        public CirclePercentBar(Context context, AttributeSet attrs) {
            this(context, attrs, 0);
        }
    
        public CirclePercentBar(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
            mContext=context;
            TypedArray typedArray=context.obtainStyledAttributes(attrs,R.styleable.CirclePercentBar,defStyleAttr,0);
            mArcColor = typedArray.getColor(R.styleable.CirclePercentBar_arcColor,0xff0000);
            mArcWidth = typedArray.getDimensionPixelSize(R.styleable.CirclePercentBar_arcWidth, DisplayUtil.dp2px(context, 20));
            mCenterTextColor = typedArray.getColor(R.styleable.CirclePercentBar_centerTextColor, 0x0000ff);
            mCenterTextSize = typedArray.getDimensionPixelSize(R.styleable.CirclePercentBar_centerTextSize, DisplayUtil.dp2px(context, 20));
            mCircleRadius = typedArray.getDimensionPixelSize(R.styleable.CirclePercentBar_circleRadius, DisplayUtil.dp2px(context, 100));
            arcStartColor = typedArray.getColor(R.styleable.CirclePercentBar_arcStartColor,
                    ContextCompat.getColor(mContext, R.color.green));
            arcEndColor = typedArray.getColor(R.styleable.CirclePercentBar_arcEndColor,
                    ContextCompat.getColor(mContext, R.color.yellow));
    
            typedArray.recycle();
    
            initPaint();
    
        }
    
        private void initPaint() {
    
            startCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            startCirclePaint.setStyle(Paint.Style.FILL);
            //startCirclePaint.setStrokeWidth(mArcWidth);
            startCirclePaint.setColor(arcStartColor);
    
            arcCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            arcCirclePaint.setStyle(Paint.Style.STROKE);
            arcCirclePaint.setStrokeWidth(mArcWidth);
            arcCirclePaint.setColor(ContextCompat.getColor(mContext,R.color.colorAccent));
            arcCirclePaint.setStrokeCap(Paint.Cap.ROUND);
    
            arcPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            arcPaint.setStyle(Paint.Style.STROKE);
            arcPaint.setStrokeWidth(mArcWidth);
            arcPaint.setColor(mArcColor);
            arcPaint.setStrokeCap(Paint.Cap.ROUND);
    
            centerTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            centerTextPaint.setStyle(Paint.Style.STROKE);
            centerTextPaint.setColor(mCenterTextColor);
            centerTextPaint.setTextSize(mCenterTextSize);
    
            //圓弧的外接矩形
            arcRectF = new RectF();
    
            //文字的邊界矩形
            textBoundRect = new Rect();
    
        }
    
    
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
            setMeasuredDimension(measureDimension(widthMeasureSpec),measureDimension(heightMeasureSpec));
        }
    
        private int measureDimension(int measureSpec) {
            int result;
            int specMode=MeasureSpec.getMode(measureSpec);
            int specSize=MeasureSpec.getSize(measureSpec);
            if(specMode==MeasureSpec.EXACTLY){
                result=specSize;
            }else{
                result=mCircleRadius*2;
                if(specMode==MeasureSpec.AT_MOST){
                    result=Math.min(result,specSize);
                }
            }
            return result;
        }
    
        @Override
        protected void onDraw(Canvas canvas) {
    
            canvas.rotate(-90, getWidth()/ 2, getHeight()/ 2);
    
            arcRectF.set(getWidth()/2-mCircleRadius+mArcWidth/2,getHeight()/2-mCircleRadius+mArcWidth/2
                    ,getWidth()/2+mCircleRadius-mArcWidth/2,getHeight()/2+mCircleRadius-mArcWidth/2);
    
    
            canvas.drawArc(arcRectF, 0,360,false,arcCirclePaint);
    
            arcPaint.setShader(new SweepGradient(getWidth()/2,getHeight()/2,arcStartColor,arcEndColor));
            canvas.drawArc(arcRectF, 0,360* mCurData /100,false,arcPaint);
    
            canvas.rotate(90, getWidth()/ 2, getHeight()/ 2);
            canvas.drawCircle(getWidth()/2,getHeight()/2-mCircleRadius+mArcWidth/2,mArcWidth/2,startCirclePaint);
    
            String data= String.valueOf(mCurData) +"%";
            centerTextPaint.getTextBounds(data,0,data.length(),textBoundRect);
            canvas.drawText(data,getWidth()/2-textBoundRect.width()/2,getHeight()/2+textBoundRect.height()/2,centerTextPaint);
    
        }
    
        public void setPercentData(float data, TimeInterpolator interpolator){
            ValueAnimator valueAnimator=ValueAnimator.ofFloat(mCurData,data);
            valueAnimator.setDuration((long) (Math.abs(mCurData-data)*30));
            valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator valueAnimator) {
                    float value= (float) valueAnimator.getAnimatedValue();
                    mCurData=(float)(Math.round(value*10))/10;
                    invalidate();
                }
            });
            valueAnimator.setInterpolator(interpolator);
            valueAnimator.start();
        }
    }

    ?

    ?

    (2)其中需要用到的類

    public class DisplayUtil {
        public static int px2dp(Context context,float pxValue){
            final float scale=context.getResources().getDisplayMetrics().density;
            return (int)(pxValue/scale+0.5f);
        }
        public static int dp2px(Context context,float dpValue){
            final float scale=context.getResources().getDisplayMetrics().density;
            return (int)(dpValue*scale+0.5f);
        }
    }

    (3)attrs.xml

    <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <declare-styleable name="CirclePercentBar">
            <attr name="arcColor" format="color"/>
            <attr name="arcWidth" format="dimension"/>
            <attr name="centerTextColor" format="color"/>
            <attr name="centerTextSize" format="dimension"/>
            <attr name="circleRadius" format="dimension"/>
            <attr name="arcStartColor" format="color"/>
            <attr name="arcEndColor" format="color"/>
        </declare-styleable>
    </resources>

    (4)在activity_main里面寫布局

    <?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"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
     
        <com.example.administrator.textc.CirclePercentBar
            android:id="@+id/circle_bar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="20dp"
            android:layout_gravity="center_horizontal"
            app:arcWidth="30dp"
            app:circleRadius="100dp"
            app:centerTextSize="30sp"
            app:arcColor="@color/colorPrimary"
            app:centerTextColor="@color/colorAccent"
            app:arcStartColor="@android:color/holo_green_light"/>
    
        <Button
            android:id="@+id/start_btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="隨機"/>
    </LinearLayout>
    

    (6)編程實現效果:

    public class MainActivity extends AppCompatActivity {
        CirclePercentBar circlePercentBar;
        Button startBtn;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            circlePercentBar= (CirclePercentBar) findViewById(R.id.circle_bar);
            circlePercentBar.setPercentData(55.2f,new DecelerateInterpolator());
    
            startBtn= (Button) findViewById(R.id.start_btn);
            startBtn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    circlePercentBar.setPercentData((float) (100*Math.random()),new DecelerateInterpolator());
                }
            });
        }
    }

    ?

    ?

    本文摘自 :https://blog.51cto.com/u

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