public final void measure(int widthMeasureSpec, int heightMeasureSpec) 
protected final void setMeasuredDimension(int measuredWidth, int measuredHeight) 
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)

public void layout(int l, int t, int r, int b)
protected boolean setFrame(int left, int top, int right, int bottom)
protected void onLayout(boolean changed, int left, int top, int right, int bottom)

public void draw(Canvas canvas)
protected void onDraw(Canvas canvas)

public class PercentView extends View {
private final static String TAG = PercentView.class.getSimpleName();
private Paint mPaint;
public PercentView(Context context) {
super(context);
}
public PercentView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public PercentView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
Log.e(TAG, "onMeasure--widthMode-->" + widthMode);
switch (widthMode) {
case MeasureSpec.EXACTLY:
break;
case MeasureSpec.AT_MOST:
break;
case MeasureSpec.UNSPECIFIED:
break;
}
Log.e(TAG, "onMeasure--widthSize-->" + widthSize);
Log.e(TAG, "onMeasure--heightMode-->" + heightMode);
Log.e(TAG, "onMeasure--heightSize-->" + heightSize);
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
Log.e(TAG, "onLayout");
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(Color.GRAY);
// FILL填充, STROKE描边,FILL_AND_STROKE填充和描边
mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
int with = getWidth();
int height = getHeight();
Log.e(TAG, "onDraw---->" + with + "*" + height);
float radius = with / 4;
canvas.drawCircle(with / 2, with / 2, radius, mPaint);
mPaint.setColor(Color.BLUE);
RectF oval = new RectF(with / 2 - radius, with / 2 - radius, with / 2
+ radius, with / 2 + radius); //用于定义的圆弧的形状和大小的界限
canvas.drawArc(oval, 270, 120, true, mPaint); //根据进度画圆弧
}
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.whoislcj.views.PercentView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.whoislcj.views.PercentView
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_margin="10dp" />
</LinearLayout>