Android中如何制作電池電量進度條：上下滾動圖片的進度條（battery）

最近，制作一個app,需要模擬一個電池電量的進度條，根據電量多少來設置百分比，進度條不斷上下滾動，就像平時手機充電一樣的電池電量進度條。我就自定義view實現了電量進度條。修改圖片就可以達到自己想要的效果

一、自定義View，Battery.java,循環刷新界面,兩張圖片上下滾動，達到不斷向右移動的效果。挺有意思的

package com.example.battery;
     
     
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;
     
public class Battery extends View {
    public float currentX = 80;
    public float currentY = 80;
    private float secondY = 80;
    private Paint mPaint = new Paint();
    private Context mContext;
    private Handler mHandler;
    private Bitmap mBmp;
    private int speedTime = 20;
         
    private float with = 200;
    private float height = 50;
    private float percentage = 0.5f;
     
    public Battery(Context context) {
        super(context);
        this.mContext = context;
             
    }
  // 查看本欄目更多精彩內容：http://www.bianceng.cn/OS/extra/
    public Battery(Context context, AttributeSet set) {
        super(context, set);
        this.mContext = context;
        init();
    }
     
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        with = this.getWidth();
        height = this.getHeight();
             
        mPaint.setColor(Color.BLUE);
        Resources res = mContext.getResources();
        BitmapDrawable bmpDraw = (BitmapDrawable) res
                .getDrawable(R.drawable.loading_pic);
        mBmp = bmpDraw.getBitmap();
             
        canvas.clipRect(0, 0, with*percentage, height);
             
        canvas.drawBitmap(mBmp, 0, currentY, mPaint);
             
        canvas.drawBitmap(mBmp, 0, secondY, mPaint);
    }
     
    private void init() {
        percentage = 0;
             
        mHandler = new Handler() {
            public void handleMessage(Message msg) {
                switch (msg.what) {
                case 1:
                    currentX ++;
                    currentY ++;
                    if (mBmp != null && currentY > mBmp.getHeight()){
                        currentY = -mBmp.getHeight();
                    }
                    if (mBmp != null){
                        secondY = currentY+mBmp.getHeight();
                        if (secondY >= mBmp.getHeight()){
                            secondY = currentY-mBmp.getHeight();
                        }
                    }
                         
                    percentage = percentage + 0.003f;
                    if (percentage > 1){
                        percentage = 0;
                    }
                    // 每次計算後都發送消息進入下一次循環，並刷新界面
                    mHandler.sendEmptyMessageDelayed(1, speedTime);
                    postInvalidate();
                    break;
                }
                super.handleMessage(msg);
                postInvalidate();
            }
        };
             
        // 首次循環刷新界面
        mHandler.sendEmptyMessageDelayed(1, speedTime);
    }
}