android开发自定义五星好评Demo

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class CustomStartView extends View {

    private Bitmap originalStart;
    private Bitmap gradeStart;
    private int startNumber;

    private int startHeight,startwidth;
    private Paint gradePaint;
    private int endGrade;

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

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

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

        TypedArray typedArray=context.obtainStyledAttributes(attrs,R.styleable.CustomStartView);
        int original=typedArray.getResourceId(R.styleable.CustomStartView_originalStar,0);
        int grade=typedArray.getResourceId(R.styleable.CustomStartView_focusStar,0);
        startNumber=typedArray.getInt(R.styleable.CustomStartView_startNumber,0);
        originalStart=BitmapFactory.decodeResource(getResources(),original);
        gradeStart=BitmapFactory.decodeResource(getResources(),grade);
        typedArray.recycle();

        gradePaint=new Paint();
        gradePaint.setAntiAlias(true);

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        startHeight=gradeStart.getHeight();
        startwidth=gradeStart.getWidth();

        int height=startHeight;
        int width=startwidth*startNumber;
        setMeasuredDimension(width,height);
    }

    @Override
    protected void onDraw(Canvas canvas) {


        for (int i=0;i<startNumber;i++){
            int x=i*startwidth;
            if (endGrade>i){
                canvas.drawBitmap(gradeStart,x,0,null);
            }else {
                canvas.drawBitmap(originalStart,x,0,null);
            }
        }


    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {

        switch (event.getAction()){

            case MotionEvent.ACTION_DOWN:
            case MotionEvent.ACTION_MOVE:
                int x= (int) event.getX();
                int y= (int) event.getY();
                int currentStart=x/startwidth+1;
                if (currentStart<0){
                    currentStart=0;
                }else if (currentStart>5){
                    currentStart=5;
                }

                endGrade=currentStart;
                invalidate();
                break;
            case MotionEvent.ACTION_UP:

                break;
        }

        return true;

    }
}