第一步：新建文件Circle.java

package com.lancy.demo.democircle.widget;

 

import android.annotation.SuppressLint;

import android.content.Context;

import android.content.res.TypedArray;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.view.View;

 

import com.lancy.demo.democircle.R;

 

public class Circle extends View {

    private Paint mPaint;

 

    private float strokeWidth = 10;

    private float progress = 0;

    private int defaultColor;

    private int activeColor;

 

    public Circle(Context context, AttributeSet attrs) {

        super(context, attrs);

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.circle);

 

        strokeWidth = a.getDimension(R.styleable.circle_strokeWidth, strokeWidth);

        progress = a.getFraction(R.styleable.circle_progress, 360, 100, 10);

        defaultColor = a.getColor(R.styleable.circle_defaultColor, Color.GRAY);

        activeColor = a.getColor(R.styleable.circle_activeColor, Color.BLUE);

       

        a.recycle();

 

    }

 

    public Circle(Context context) {

 

        this(context, null);

    }

 

    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        // TODO Auto-generated method stub

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        final int minimumWidth = getSuggestedMinimumWidth();

        final int minimumHeight = getSuggestedMinimumHeight();

        int viewWidth = resolveMeasured(widthMeasureSpec, minimumWidth);

        int viewHeight = resolveMeasured(heightMeasureSpec, minimumHeight);

        setMeasuredDimension(viewWidth, viewHeight);

 

    }

 

    private int resolveMeasured(int measureSpec, int desired) {

        int result = 0;

        int specSize = MeasureSpec.getSize(measureSpec);

        switch (MeasureSpec.getMode(measureSpec)) {

        case MeasureSpec.UNSPECIFIED:

            result = desired;

            break;

        case MeasureSpec.AT_MOST:

            result = Math.max(specSize, desired);

            break;

        case MeasureSpec.EXACTLY:

        default:

            result = specSize;

        }

        return result;

    }

 

    @SuppressLint("DrawAllocation")

    @Override

    protected void onDraw(Canvas canvas) {

        // TODO Auto-generated method stub

        super.onDraw(canvas);

        int width = getWidth();

        int height = getHeight();

        float h = width > height ? height : width;

 

        Paint p = new Paint();

        p.setColor(defaultColor);

        p.setStyle(Paint.Style.STROKE);

        p.setAntiAlias(true);

        p.setStrokeWidth(strokeWidth);

        RectF oval1 = new RectF(strokeWidth / 2, strokeWidth / 2, h-strokeWidth / 2, h-strokeWidth / 2);

        canvas.drawArc(oval1, 0, 360, false, p);

        p.setColor(activeColor);

        canvas.drawArc(oval1, 270, progress, false, p);//小弧形

 

    }

 

    public void setProgress(float progress) {

        this.progress = progress / 100 * 360;

        invalidate();

 

    }

 

    public float getProgress() {

        return progress * 100 / 360;

    }

 

}

 

第二步  新建attrs.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

     <declare-styleable name="circle">

         <attr name="strokeWidth" format="dimension"></attr>

         <attr name="progress" format="fraction"></attr>

         <attr name="defaultColor" format="color"></attr>

         <attr name="activeColor" format="color"></attr>

         

         

     </declare-styleable>

</resources>

 

第三步  建布局文件 circle.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:circle="http://schemas.android.com/apk/res/com.lancy.demo.democircle" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:padding="50dp" 
android:gravity="center" 
android:orientation="vertical" > 

<com.lancy.demo.democircle.widget.Circle 
android:id="@+id/circle" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
circle:defaultColor="#95a1aa" 
circle:activeColor="#1290dd" 
circle:strokeWidth="10dp" 
circle:progress="25%" 
/> 

<!-- --> 

</LinearLayout> 

 

第三步 建MainActivity.java

 package com.lancy.demo.democircle;

 

import android.app.Activity;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.Bundle;

import android.util.Log;

 

import com.lancy.demo.democircle.widget.Circle;

 

public class MainActivity extends Activity {

    Circle circle;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);

 

        setContentView(R.layout.circle);

        circle = (Circle) findViewById(R.id.circle);

       

        IntentFilter filter = new IntentFilter();

        filter.addAction(Intent.ACTION_TIME_TICK);

        registerReceiver(new TimeReceiver(), filter);

    }

   

   

    class TimeReceiver extends BroadcastReceiver{

 

        @Override

        public void onReceive(Context context, Intent intent) {

            Log.i("TimeReceiver----------------", intent.getAction());

            circle.setProgress(circle.getProgress()-1);

           

        }

       

    }

 

}