Battery circle like Battery Widget Reborn

问题

I am trying to make draw a circle based on the battery percentage. I have the following code:

Bitmap.Config conf = Bitmap.Config.ARGB_8888; // see other conf types
Bitmap bmp = Bitmap.createBitmap(200, 200, conf);

Paint mPaint = new Paint();
mPaint.setDither(true);
mPaint.setColor(Color.BLUE);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(5);

circle = new Path();
circle.addCircle(100, 100, level, Direction.CW);

Canvas canvas = new Canvas(bmp);
canvas.drawPath(circle, mPaint);

I am trying to get similar to Battery Widget Reborn, where its a circle path drawn based on a percentage, could someone please help.

Edit:

below is a shot of what i am trying to accomplish

回答1:

You should be able to do this with Path.addArc(). You just have to define the bounds of the enclosing rectangle, the start angle, and how many degrees to sweep.

Something like:

RectF box = new RectF(0,0,bmp.getWidth(),bmp.getHeight());
float sweep = 360 * level * 0.01f;
circle.addArc(box, 0, sweep);

回答2:

You can use this class as a full working example. You can also add the text in the view, but that goes beyond the question...

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.view.View;

public class DrawView extends View {

    Paint mPaint = new Paint();

    public DrawView(Context context) {
        super(context);            
    }

    @Override
    public void onDraw(Canvas canvas) {

        Paint mPaint = new Paint(Paint.FILTER_BITMAP_FLAG |
                Paint.DITHER_FLAG |
                Paint.ANTI_ALIAS_FLAG);
        mPaint.setDither(true);
        mPaint.setColor(Color.GRAY);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(1);

        int size = 200;
        int radius = 190;
        int delta = size - radius;
        int arcSize = (size - (delta / 2)) * 2;
        int percent = 42;

        //Thin circle
        canvas.drawCircle(size, size, radius, mPaint);

        //Arc
        mPaint.setColor(Color.parseColor("#33b5e5"));
        mPaint.setStrokeWidth(15);
        RectF box = new RectF(delta,delta,arcSize,arcSize);
        float sweep = 360 * percent * 0.01f;
        canvas.drawArc(box, 0, sweep, false, mPaint);

    }

}

来源：https://stackoverflow.com/questions/14988701/battery-circle-like-battery-widget-reborn

标签

android

canvas

battery