Android 自定义UI--电池

 首先看一下效果图，

  下面看代码：

/**
 *
 */
package com.example.batterydemo;

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

/**
 * @author kince
 * @category 自定义View电池
 * @time 2014.2.13
 * @qq 543781062
 *
 */
public class BatteryView extends View {

    /**
     * 画笔信息
     */
    private Paint mBatteryPaint;
    private Paint mPowerPaint;
    private float mBatteryStroke = 2f;
    /**
     * 屏幕高宽
     */
    private int measureWidth;
    private int measureHeigth;
    /**
     *
     * 电池参数
     */
    private float mBatteryHeight = 30f; // 电池的高度
    private float mBatteryWidth = 60f; // 电池的宽度
    private float mCapHeight = 15f;
    private float mCapWidth = 5f;
    /**
     *
     * 电池电量
     */
    private float mPowerPadding = 1;
    private float mPowerHeight = mBatteryHeight - mBatteryStroke
            - mPowerPadding * 2; // 电池身体的高度
    private float mPowerWidth = mBatteryWidth - mBatteryStroke - mPowerPadding
            * 2;// 电池身体的总宽度
    private float mPower = 0f;
    /**
     *
     * 矩形
     */
    private RectF mBatteryRect;
    private RectF mCapRect;
    private RectF mPowerRect;

    public BatteryView(Context context) {
        super(context);
        initView();
    }

    public BatteryView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView();
    }

    public BatteryView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView();
    }

    public void initView() {
        /**
         * 设置电池画笔
         */
        mBatteryPaint = new Paint();
        mBatteryPaint.setColor(Color.GRAY);
        mBatteryPaint.setAntiAlias(true);
        mBatteryPaint.setStyle(Style.STROKE);
        mBatteryPaint.setStrokeWidth(mBatteryStroke);
        /**
         * 设置电量画笔
         */
        mPowerPaint = new Paint();
        mPowerPaint.setColor(Color.RED);
        mPowerPaint.setAntiAlias(true);
        mPowerPaint.setStyle(Style.FILL);
        mPowerPaint.setStrokeWidth(mBatteryStroke);
        /**
         * 设置电池矩形
         */
        mBatteryRect = new RectF(mCapWidth, 0, mBatteryWidth, mBatteryHeight);
        /**
         * 设置电池盖矩形
         */
        mCapRect = new RectF(0, (mBatteryHeight - mCapHeight) / 2, mCapWidth,
                (mBatteryHeight - mCapHeight) / 2 + mCapHeight);
        /**
         * 设置电量矩形
         */
        mPowerRect = new RectF(mCapWidth + mBatteryStroke / 2 + mPowerPadding
                + mPowerWidth * ((100f - mPower) / 100f), // 需要调整左边的位置
                mPowerPadding + mBatteryStroke / 2, // 需要考虑到 画笔的宽度
                mBatteryWidth - mPowerPadding * 2, mBatteryStroke / 2
                        + mPowerPadding + mPowerHeight);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.save();
        canvas.translate(measureWidth / 2, measureHeigth / 2);
        canvas.drawRoundRect(mBatteryRect, 2f, 2f, mBatteryPaint); // 画电池轮廓需要考虑 画笔的宽度
        canvas.drawRoundRect(mCapRect, 2f, 2f, mBatteryPaint);// 画电池盖
        canvas.drawRect(mPowerRect, mPowerPaint);// 画电量
        canvas.restore();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        measureWidth = MeasureSpec.getSize(widthMeasureSpec);
        measureHeigth = MeasureSpec.getSize(heightMeasureSpec);
        setMeasuredDimension(measureWidth, measureHeigth);
    }

    /**]
     * @category 设置电池电量
     * @param power
     */
    public void setPower(float power) {
        mPower = power;
        if (mPower < 0) {
            mPower = 0;
        }
        mPowerRect = new RectF(mCapWidth + mBatteryStroke / 2 + mPowerPadding
                + mPowerWidth * ((100f - mPower) / 100f), // 需要调整左边的位置
                mPowerPadding + mBatteryStroke / 2, // 需要考虑到 画笔的宽度
                mBatteryWidth - mPowerPadding * 2, mBatteryStroke / 2
                        + mPowerPadding + mPowerHeight);
        invalidate();
    }

}

  代码已经注释得比较清楚了，大家自己看吧，不懂的方法可以去看一下api。