android 圆圈扩大效果,【Android自定义控件】圆圈交替，仿progress效果

还是我们自定View的那几个步骤：

1、自定义View的属性

2、在View的构造方法中获得我们自定义的属性

3、重写onMesure (不是必须)

4、重写onDraw

自定义View的属性

自定义View，并且使用自定义的View

public class ProgressView extends View {

/**

* 第一圈的颜色

*/

private int mFirstColor;

/**

* 第二圈的颜色

*/

private int mSecondColor;

/**

* 圈的宽度

*/

private int mCircleWidth;

/**

* 画笔

*/

private Paint mPaint;

/**

* 当前进度

*/

private int mProgress;

/**

* 速度

*/

private int mSpeed;

/**

* 是否应该开始下一个

*/

private boolean isNext = false;

public ProgressView(Context context) {

this(context, null);

}

public ProgressView(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

public ProgressView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

TypedArray typedArray = context.getTheme().obtainStyledAttributes(attrs, R.styleable.progressStyle,defStyleAttr,0);

int n = typedArray.getIndexCount();

for (int i =0 ;i < n ; i ++){

int attr =typedArray.getIndex(i);

switch (attr){//这里的0,1,2，3对应attrs中declare-styleable name="progressStyle"数组元素的顺序，我是为了举例方便，实际开发中不要这样写

case 0:

mFirstColor = typedArray.getColor(attr, Color.BLACK);

break;

case 1:

mSecondColor = typedArray.getColor(attr, Color.RED);

break;

case 2:

mCircleWidth = typedArray.getDimensionPixelSize(attr,(int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,

16,getResources().getDisplayMetrics()));

break;

case 3:

mSpeed = typedArray.getInt(attr,20);

break;

}

}

typedArray.recycle();

mPaint = new Paint();

startMyThread();

}

@Override

protected void onDraw(Canvas canvas) {

int center = getWidth() / 2; // 获取圆心的x坐标

int radius = (center - mCircleWidth)/2 ;// 半径

mPaint.setAntiAlias(true);

mPaint.setStrokeWidth(mCircleWidth);

mPaint.setStyle(Paint.Style.STROKE);

RectF rectf = new RectF(center-radius,center-radius,center+radius,center+radius);

//颜色的切换

if(!isNext){

canvas.save();

mPaint.setColor(mFirstColor);// 设置圆环的颜色

canvas.drawCircle(center,center,radius,mPaint);//划出圆圈

mPaint.setColor(mSecondColor);

canvas.drawArc(rectf,-90,mProgress,false,mPaint);//根据进度画圆弧

canvas.restore();

}else {

canvas.save();

mPaint.setColor(mSecondColor);// 设置圆环的颜色

canvas.drawCircle(center,center,radius,mPaint);

mPaint.setColor(mFirstColor);

canvas.drawArc(rectf,-90,mProgress,false,mPaint);

canvas.restore();

}

}

private void startMyThread() {

new Thread(new Runnable() {

@Override

public void run() {

while (true){

mProgress++;//进度

if(mProgress == 360){//当360度时候值变为初始状态

mProgress = 0;

if(!isNext){//设置是否切换颜色开关

isNext = true;

}else {

isNext = false;

}

}

postInvalidate();

try {

Thread.sleep(mSpeed);

}catch (InterruptedException e){

e.printStackTrace();

}

}

}

}).start();;

}

以上代码就是自定义View的全部代码，使用的话没什么多说的 直接在Xml中引用这个新建的ProgressView就可以了

重画ondraw   不多解释直接看代码

@Override

protected void onDraw(Canvas canvas) {

int center = getWidth() / 2; // 获取圆心的x坐标

int radius = (center - mCircleWidth)/2 ;// 半径

mPaint.setAntiAlias(true);

mPaint.setStrokeWidth(mCircleWidth);

mPaint.setStyle(Paint.Style.STROKE);

RectF rectf = new RectF(center-radius,center-radius,center+radius,center+radius);

if(!isNext){

canvas.save();

mPaint.setColor(mFirstColor);// 设置圆环的颜色

canvas.drawCircle(center,center,radius,mPaint);//划出圆圈

mPaint.setColor(mSecondColor);

canvas.drawArc(rectf,-90,mProgress,false,mPaint);//根据进度画圆弧

canvas.restore();

}else {

canvas.save();

mPaint.setColor(mSecondColor);// 设置圆环的颜色

canvas.drawCircle(center,center,radius,mPaint);

mPaint.setColor(mFirstColor);

canvas.drawArc(rectf,-90,mProgress,false,mPaint);

canvas.restore();

}

}

效果是不是和progress相似呢 ，自己试试看吧

原文：http://blog.youkuaiyun.com/honjane/article/details/38386513