| 一、概述 |
在上一篇博文中，我们给大家介绍了Android自定义控件系列的基础篇。链接：http://www.cnblogs.com/jerehedu/p/4360066.html
这一篇博文中，我们将在基础篇的基础上，再通过重写ondraw（）方法和自定义属性实现圆形进度条，效果如图所示：
| 二、实现步骤 |
1、 编写自定义组件MyCircleProgress扩展View
public class MyCircleProgress extends View {
…
}
2、 在MyCircleProgress类中，定制属性
public int progress = 0;//进度实际值,当前进度
/**
* 自定义控件属性，可灵活的设置圆形进度条的大小、颜色、类型等
*/
private int mR;//圆半径，决定圆大小
private int bgColor;//圆或弧的背景颜色
private int fgColor;//圆或弧的前景颜色，即绘制时的颜色
private int drawStyle; //绘制类型 FILL画圆形进度条，STROKE绘制弧形进度条
private int strokeWidth;//STROKE绘制弧形的弧线的宽度
private int max;//最大值，设置进度的最大值
/**
* 设置进度，此为线程安全控件，由于考虑多线的问题，需要同步
*/
public synchronized void setProgress(int progress) {
if(progress<0){
progress=0;
}else if(progress>max){
progress=max;
}else{
this.progress = progress;
}
}
public int getMax() {
return max; }
3、 为定制的属性编写attrs.xml资源，该资源文件放在res/values目录下，内容如下：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="CircleProgressBar">
<attr name="bgColor" format="color"/>
<attr name="fgColor" format="color"/>
<attr name="r" format="integer"/>
<attr name="strokeWidth" format="integer"/>
<attr name="drawStyle">
<enum name="STROKE" value="0"></enum>
<enum name="FILL" value="1"></enum>
</attr>
<attr name="max" format="integer"/>
</declare-styleable>
</resources>
4、 在MyCircleProgress类中定义构造函数，初始化属性
private void initProperty(AttributeSet attrs){
TypedArray tArray = context.obtainStyledAttributes(attrs, R.styleable.CircleProgressBar);
mR=tArray.getInteger(R.styleable.CircleProgressBar_r,10);
bgColor=tArray.getColor(R.styleable.CircleProgressBar_bgColor, Color.GRAY);
fgColor=tArray.getColor(R.styleable.CircleProgressBar_fgColor, Color.RED);
drawStyle=tArray.getInt(R.styleable.CircleProgressBar_drawStyle, 0);
strokeWidth=tArray.getInteger(R.styleable.CircleProgressBar_strokeWidth, 10);
max=tArray.getInteger(R.styleable.CircleProgressBar_max, 100);
}
public MyCircleProgress(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
this.paint = new Paint();
this.paint.setAntiAlias(true); // 消除锯齿
this.paint.setStyle(Style.STROKE); // 绘制空心圆或 空心矩形
initProperty(attrs);
}
5、 在MainActivity中布局文件中添加MyCircleProgress组件，如下所示
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res/com.jereh.mydrawcircleprogress"
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.jereh.views.MyCircleProgress
android:id="@+id/MyCircleProgress"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:r="45"
app:strokeWidth="10"
app:bgColor="#cccccc"
app:fgColor="#ff0000"
app:drawStyle="FILL"
app:max="50"
/>
</RelativeLayout>
6、 自定义组件MyCircleProgress中重写onDraw方法：
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int center = getWidth() / 2; // 圆心位置
this.paint.setColor(bgColor);
this.paint.setStrokeWidth(strokeWidth);
canvas.drawCircle(center, center, mR, this.paint);
// 绘制圆环
this.paint.setColor(fgColor);
if(drawStyle==0){
this.paint.setStyle(Style.STROKE);
opt=false;
}else{
this.paint.setStyle(Style.FILL);
opt=true;
}
int top = (center - mR);
int bottom = (center + mR);
RectF oval = new RectF(top, top, bottom, bottom);
canvas.drawArc(oval, 270, 360*progress/max, opt, paint);
}
7、编写MainActivity
public class MainActivity extends Activity {
private MyCircleProgress progressView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressView = (MyCircleProgress) findViewById(R.id.MyCircleProgress);
new ProgressAnimation().execute();
}
class ProgressAnimation extends AsyncTask<Void, Integer, Void> {
@Override
protected Void doInBackground(Void... params) {
//进度值不断的变化
for (int i = 0; i < progressView.getMax(); i++) {
try {
publishProgress(i);
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return null;
}
@Override
protected void onProgressUpdate(Integer... values) {
//更新进度值
progressView.setProgress(values[0]);
progressView.invalidate();
super.onProgressUpdate(values);
}
}
}
