Android电量View

电量View，效果如下：

1电量组件

主要分三部分电池的外框，电池的头和电量。

/**
 * 电量显示控件
 */
public class BatteryStateView extends View {
    private int mPower = 100;

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

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

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int batteryLeft = 0;
        int batteryTop = 2;
        int batteryWidth = 60;//电池的宽
        int batteryHeight = 25;//电池的高

        int batteryHeadWidth = 6;//头部的宽
        int batteryHeadHeight = 6;//头部的高

        int batteryInsideMargin = 3;

        //先画外框
        Paint paint = new Paint();
        paint.setColor(Color.WHITE);
        paint.setAntiAlias(true);
        paint.setStyle(Style.STROKE);
        Rect rect = new Rect(batteryLeft, batteryTop, batteryLeft + batteryWidth, batteryTop + batteryHeight);
        canvas.drawRect(rect, paint);

        //画电池头
        Paint paintHead = new Paint(paint);
        paintHead.setColor(Color.WHITE);
        paintHead.setStyle(Style.FILL);
        int headLeft = batteryLeft + batteryWidth;
        int headTop = batteryTop + batteryHeight / 2 - batteryHeadHeight / 2;
        int headRight = headLeft + batteryHeadWidth;
        int headBottom = headTop + batteryHeadHeight;
        Rect headRect = new Rect(headLeft, headTop, headRight, headBottom);
        canvas.drawRect(headRect, paintHead);

        //画电量
        float powerPercent = mPower / 100.0f;
        Paint paintBattery = new Paint(paint);
        paintBattery.setColor(Color.GREEN);
        paintBattery.setStyle(Style.FILL);
        if (powerPercent != 0) {
            int pLeft = batteryLeft + batteryInsideMargin;
            int pTop = batteryTop + batteryInsideMargin;
            int pRight = pLeft - batteryInsideMargin + (int) ((batteryWidth - batteryInsideMargin) * powerPercent);
            int pBottom = pTop + batteryHeight - batteryInsideMargin * 2;
            Rect powerPercentRect = new Rect(pLeft, pTop, pRight, pBottom);
            canvas.drawRect(powerPercentRect, paintBattery);
        }
    }

    public void setPower(int power) {
        mPower = power;
        if (mPower < 0)
            mPower = 0;
        invalidate();
    }

}

2 电量监听

监听电量发生改变的事件。

/**
 * 电量显示工具类
 */
public class BatteryStateViewUtil {

    /**
     * 创建电量监听
     * @param view
     * @return
     */
    public static BroadcastReceiver createBroadcastReceiver(BatteryStateView view) {
        return new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction())) {
                    int level = intent.getIntExtra("level", 0);
                    int scale = intent.getIntExtra("scale", 100);
                    int power = level * 100 / scale;
                    view.setPower(power);
                }
            }
        };
    }

}

3 Avtivity中添加监听

    @Override
    protected void onResume() {
        register();
        super.onResume();
    }

    @Override
    protected void onPause() {
        unregister();
        super.onPause();
    }

    /**注册*/
    public void register() {
        if (batteryChangedReceiver == null)
            batteryChangedReceiver = BatteryStateViewUtil.createBroadcastReceiver(binding.batteryStateView);//binding.batteryStateView是电量的组件
        registerReceiver(batteryChangedReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
    }

    /**取消注册*/
    public void unregister() {
        unregisterReceiver(batteryChangedReceiver);
    }