圆环百分比自定义View

Android自定义View的学习是初级开发到中级开发的一个重要学习内容。今天就自己做一个自定义小控件。该控件为圆环百分比显示，并显示绘画的过程动画。

自定义View开发步骤：

①自定义View的属性；

②在View的构造方法中构造我们的自定义View;

③重写onMeasure();

④重写onDraw();
⑤其他外部接口方法。

①自定义View的属性：创建res/values/attr.xml

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

    name="firstColor" format="color" />
    name="circleWidth" format="dimension" />
    name="speed" format="integer" />

    name="CustomProgressBar">
        name="firstColor" />
        name="circleWidth" />
        name="speed" />
    

②在View的构造方法中构造我们的自定义View

public class PercentProgressBar extends View {
    private final String TAG = "PercentProgressBar";
    //画笔
    private  Paint mPaint;
    //动画速度
    private  int mSpeed;
    //圆环宽度
    private  int mCircleWidth;
    //默认基体颜色
    private  int mFirstColor;
    //进度
    private int mProgress;
    //各部分所占角度
    private int[] percents;
    //各部分的颜色
    private int[] colors;
    //判断是否开始动画
    private boolean start = false;

    public PercentProgressBar(Context context) {
        this(context, null);
    }

    public PercentProgressBar(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public PercentProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomProgressBar, defStyleAttr, 0);
        int n = a.getIndexCount();

        for(int i=0; i; i++){
            int attr = a.getIndex(i);
            switch (attr){
                case R.styleable.CustomProgressBar_firstColor:
                    mFirstColor = a.getColor(attr, Color.GREEN);
                    break;
                case R.styleable.CustomProgressBar_circleWidth:
                    mCircleWidth = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, 20, getResources().getDisplayMetrics()));
                    break;
                case R.styleable.CustomProgressBar_speed:
                    mSpeed = a.getInt(attr, 20);
                    break;
            }
        }
        a.recycle();
        mPaint = new Paint();
        colors = new int[]{Color.YELLOW, Color.GREEN, Color.BLUE};
    }
...
}

③重新onMeasure():（本自定义View未处理）。

④重写onDraw()

@Override
protected void onDraw(Canvas canvas) {

    int center = getWidth()/2;
    int radius = center - mCircleWidth/2;
    mPaint.setStrokeWidth(mCircleWidth);
    mPaint.setAntiAlias(true);
    mPaint.setStyle(Paint.Style.STROKE);
    RectF oval = new RectF(center - radius, center - radius, center + radius, center + radius);

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

    if(!start) return;

    if(mProgress < percents[0]){
        mPaint.setColor(colors[0]);
        canvas.drawArc(oval, 0, mProgress, false, mPaint);
    }else if(mProgress < percents[1]+percents[0]){
        mPaint.setColor(colors[0]);
        canvas.drawArc(oval, 0, percents[0], false, mPaint);
        mPaint.setColor(colors[1]);
        canvas.drawArc(oval, percents[0], mProgress-percents[0], false, mPaint);
    }else {
        mPaint.setColor(colors[0]);
        canvas.drawArc(oval, 0, percents[0], false, mPaint);
        mPaint.setColor(colors[1]);
        canvas.drawArc(oval, percents[0], percents[1], false, mPaint);
        mPaint.setColor(colors[2]);
        canvas.drawArc(oval, percents[0]+percents[1], mProgress-percents[1]-percents[0], false, mPaint);
    }
}

⑤接口方法：

/**
 * 开始各部分百分比绘画
 */
public void start(){
    start = true;
    new Thread(){
        @Override
        public void run() {
            mProgress = 0;
            while (mProgress <=360 ){
                mProgress++;
                postInvalidate();
                try {
                    this.sleep(mSpeed);
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        }
    }.start();
}

/**
 * @param values 设置各部分的值
 */
public void setPercent(float[] values){
    float sum = 0f;
    for(float value : values){
        sum += value;
    }
    percents = new int[values.length];
    for(int i=0; ilength; i++){
        percents[i] = (int) (values[i]/sum*360);
    }
    Log.i(TAG, percents[0]+","+percents[1] +","+ percents[2]);
}

/**
 * @param colors 设置自定义各部分颜色
 */
public void setDifColor(int[] colors){
    this.colors = colors;
    Log.i(TAG, colors[0]+","+colors[1] +","+ colors[2]);
}

在Activity中使用(布局文件比较简单，就不贴了)：

mPercentProgressBar = (PercentProgressBar)findViewById(R.id.progress_bar);
mPercentProgressBar.setPercent(new float[]{120, 56, 180});
mPercentProgressBar.setDifColor(new int[]{0xffff0000, 0xff00ff00,0xff0000ff});

mPercentProgressBar.start();