Android 自定义view实现进度条加载效果实例代码

package com.example.dotloadview;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Paint;import android.os.Handler;import android.util.AttributeSet;import android.view.View;/** * Created by zhouguizhi on 6/18/15. */public class DotLoadProgressView extends View {  private boolean isStart = false;  private int dotIndex =0;//点下面的角标  private int dotNumber = 0;  private Paint mPaint;  private int paddingTop = 50;  private int paddingBottom = 50;  private int paddingLeft = 30;  private int paddingRight = 30;  private Handler mHandler = new Handler();  private long DELAY_TIME = 300;  private Bitmap bitmap;  private int itemDotSpace = 10;//二个点之间的距离  private Bitmap moveBitmap ;  private Runnable mRunnable = new Runnable() {    @Override    public void run() {      if (dotNumber != 0){        dotIndex = (dotIndex + 1) % dotNumber;      }      invalidate();      mHandler.postDelayed(mRunnable, DELAY_TIME);    }  };  public DotLoadProgressView(Context context, AttributeSet attrs) {    super(context, attrs);    moveBitmap = BitmapFactory.decodeResource(getResources(),R.drawable.active_dot);    init();  }  private void init() {    mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);    mPaint.setStyle(Paint.Style.FILL);    mPaint.setDither(true);    mPaint.setAntiAlias(true);  }  @Override  protected void onDraw(Canvas canvas) {    super.onDraw(canvas);    for(int i=0;i<dotNumber;i++){      canvas.drawBitmap(bitmap,paddingLeft+i*itemDotSpace+bitmap.getWidth()*i,paddingTop,mPaint);    }    if(isStart){      canvas.drawBitmap(moveBitmap,paddingLeft+dotIndex*itemDotSpace+moveBitmap.getWidth()*dotIndex,paddingTop,mPaint);    }  }  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    int parentWidth = MeasureSpec.getSize(widthMeasureSpec);    bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.inactive_dot);    setMeasuredDimension(parentWidth,bitmap.getHeight()+paddingTop+paddingBottom);    int widthWithoutPadding = parentWidth - paddingLeft - paddingRight;    dotNumber = calculateDotsNumber(widthWithoutPadding);  }  private int calculateDotsNumber(int width) {    int number = (width / (itemDotSpace + bitmap.getWidth()));    return number;  }  public void startProgress() {    isStart = true;    dotIndex = -1;    mHandler.removeCallbacks(mRunnable);    mHandler.post(mRunnable);  }  public void stopProgress() {    isStart = false;    mHandler.removeCallbacks(mRunnable);    invalidate();  }  @Override  protected void onAttachedToWindow() {    super.onAttachedToWindow();    startProgress();  }  @Override  protected void onDetachedFromWindow() {    super.onDetachedFromWindow();    stopProgress();  }}

<?xml version="1.0" encoding="utf-8"?><RelativeLayout  xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="wrap_content">  <com.example.dotloadview.DotLoadProgressView    android:id="@+id/progress1"    android:layout_width="match_parent"    android:layout_height="wrap_content"    /></RelativeLayout>