Android自定义View实现加载进度条效果

上一篇文章总结了下自定义View的几个步骤，如果还有不清楚的同学可以先去看看Android自定义View(一) ，这篇文章和大家分享一下自定义加载进度条，效果如下

下面就以水平的进度条为列进行讲解：

1.首先还是在attrs.xml文件中自定义我们需要的属性：

2.获取我们的自定义属性：

/**
 * 字体大小
 */
private int mTextSize;
/**
 * 字体颜色
 */
private int mTextColor;
/**
 * 渐变开始的颜色
 */
private int mStartColor;
/**
 * 渐变结束的颜色
 */
private int mEndColor;
/**
 * 进度条的宽
 */
private int mProgressWidth;
/**
 * 进度条的圆角大小
 */
private int mRadius;
/**
 * 默认进度条的颜色
 */
private int mBgColor;
/**
 * 进度条的当前进度
 */
private float mCurrentProgress;
/**
 * 加载的速度
 */
private int mLoadSpeed;

private String mContent="0%";
private Rect mBounds;
private Paint mPaint;

public GradientProgressBar(Context context) {
 this(context, null);
}

public GradientProgressBar(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
}

public GradientProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 TypedArray array = context.getTheme().obtainStyledAttributes(attrs, R.styleable.GradientProgressBar, defStyleAttr, 0);
 int count = array.getIndexCount();
 for (int i = 0; i < count; i++) {
 int index = array.getIndex(i);
 switch (index) {
  case R.styleable.GradientProgressBar_textSize:
  /**
   * 默认设置为16sp，TypeValue也可以把sp转化为px
   */
  mTextSize = array.getDimensionPixelSize(index, (int) TypedValue.applyDimension(
   TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
  break;
  case R.styleable.GradientProgressBar_textColor:
  /**
   * 默认设置为黑色
   */
  mTextColor = array.getColor(index, Color.BLACK);
  break;
  case R.styleable.GradientProgressBar_startColor:
  mStartColor = array.getColor(index, Color.BLACK);
  break;
  case R.styleable.GradientProgressBar_endColor:
  mEndColor = array.getColor(index, Color.BLACK);
  break;
  case R.styleable.GradientProgressBar_bgColor:
  mBgColor = array.getColor(index, Color.BLACK);
  break;
  case R.styleable.GradientProgressBar_rectRadius:
  mRadius = array.getDimensionPixelSize(index, (int) TypedValue.applyDimension(
   TypedValue.COMPLEX_UNIT_DIP, 10, getResources().getDisplayMetrics()
  ));
  break;
  case R.styleable.GradientProgressBar_lineWidth:
  mProgressWidth=array.getDimensionPixelSize(index,(int)TypedValue.applyDimension(
   TypedValue.COMPLEX_UNIT_DIP,200,getResources().getDisplayMetrics()));
  break;
  case R.styleable.GradientProgressBar_loadSpeed:
  mLoadSpeed=array.getInt(index,10);
  break;
 }
 }
 array.recycle();
 init();
}

init()方法做如下操作

private void init(){
 mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mPaint.setAntiAlias(true);
 mBounds = new Rect();
 new Thread(new Runnable() {
 @Override
 public void run() {
  while (mCurrentProgress < mProgressWidth) {
  mCurrentProgress = mCurrentProgress + 1;
  mContent = Math.round((mCurrentProgress / mProgressWidth) * 100) + "%";
  try {
   postInvalidate();
   Thread.sleep(mLoadSpeed);
  } catch (Exception e) {
   e.printStackTrace();
  }
  }
 }
 }).start();
}

3.重写OnDraw()方法

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

 /**
 * 设置画笔的属性
 */
 mPaint.setColor(mBgColor);
 mPaint.setStyle(Paint.Style.FILL);

 /**
 * 绘制背景圆角矩形
 */
 canvas.drawRoundRect(0, 0, mProgressWidth, getHeight(), mRadius, mRadius, mPaint);

 /**
 * 设置线性渐变,设置渐变开始的起点坐标和终点坐标，渐变开始和结束的颜色，设置镜像
 * 对于这个方法不太明白的可以google一下，这里不再详细说明
 */
 LinearGradient gradient = new LinearGradient(0, getHeight() / 2, mProgressWidth, getHeight() / 2,
  mStartColor, mEndColor, Shader.TileMode.MIRROR);
 mPaint.setShader(gradient);
 /**
 * 根据进度绘制圆角矩形
 */
 canvas.drawRoundRect(0, 0, mCurrentProgress, getHeight(), mRadius, mRadius, mPaint);

 mPaint.reset();
 mPaint.setAntiAlias(true);
 mPaint.setColor(mTextColor);
 mPaint.setTextSize(mTextSize);

 /**
 * 获取绘制文本所需的矩形大小
 */
 mPaint.getTextBounds(mContent, 0, mContent.length(), mBounds);
 canvas.drawText(mContent, getWidth() / 2 - mBounds.width() / 2, getHeight() / 2 + mBounds.height() / 2, mPaint);
}

 好了，这样就完成了我们水平渐变加载进度条，下面贴出圆形进度条的源码：

public class RoundProgressBar extends View {

 /**
 * 自定义变量
 */
 private int mTextSize;
 private int mTextColor;
 private int mCircleWidth;
 private int mBgColor;
 private int mCurrentColor;
 private int mLoadSpeed;
 private float mCurrentProgress;

 private String mContent = "0%";
 private Rect mBounds;
 private Paint mPaint;

 public RoundProgressBar(Context context) {
 this(context, null);
 }

 public RoundProgressBar(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
 }

 public RoundProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 TypedArray array = context.getTheme().obtainStyledAttributes(attrs, R.styleable.RoundProgressBar, defStyleAttr, 0);
 int count = array.getIndexCount();
 for (int i = 0; i < count; i++) {
  int index = array.getIndex(i);
  switch (index) {
  case R.styleable.RoundProgressBar_textSizeRound:
   /**
   * 默认设置为16sp，TypeValue也可以把sp转化为px
   */
   mTextSize = array.getDimensionPixelSize(index, (int) TypedValue.applyDimension(
    TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
   break;
  case R.styleable.RoundProgressBar_textColorRound:
   /**
   * 默认设置为黑色
   */
   mTextColor = array.getColor(index, Color.BLACK);
   break;
  case R.styleable.RoundProgressBar_bgColorRound:
   mBgColor = array.getColor(index, Color.BLACK);
   break;
  case R.styleable.RoundProgressBar_circleWidthRound:
   mCircleWidth = array.getDimensionPixelSize(index, (int) TypedValue.applyDimension(
    TypedValue.COMPLEX_UNIT_DIP, 1, getResources().getDisplayMetrics()
   ));
   break;
  case R.styleable.RoundProgressBar_currentColorRound:
   mCurrentColor = array.getColor(index, Color.BLACK);
   break;
  case R.styleable.RoundProgressBar_loadSpeedRound:
   mLoadSpeed=array.getInt(index,10);
   break;
  }
 }
 array.recycle();
 init();
 }

 private void init() {
 mBounds = new Rect();
 mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mPaint.setAntiAlias(true);
 new Thread(new Runnable() {
  @Override
  public void run() {
  while (mCurrentProgress < 360) {
   mCurrentProgress = mCurrentProgress + 1;
   mContent = Math.round((mCurrentProgress / 360) * 100) + "%";
   postInvalidate();
   try {
   Thread.sleep(mLoadSpeed);
   } catch (Exception e) {
   e.printStackTrace();
   }
  }
  }
 }).start();
 }

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

 /**
  * 设置画笔的属性
  */
 mPaint.setColor(mBgColor);
 mPaint.setStyle(Paint.Style.STROKE);
 mPaint.setStrokeWidth(mCircleWidth);

 /**
  * 绘制圆环背景
  */
 int xPoint = getWidth() / 2;//获取圆心x的坐标
 int radius = xPoint - mCircleWidth;//获取圆心的半径
 canvas.drawCircle(xPoint, xPoint, radius, mPaint);//用于定义的圆弧的形状和大小的界限

 /**
  * 绘制圆环
  */
 mPaint.setColor(mCurrentColor);
 RectF oval = new RectF(xPoint - radius, xPoint - radius, radius + xPoint, radius + xPoint);
 canvas.drawArc(oval, -90, mCurrentProgress, false, mPaint);

 /**
  * 绘制当前进度文本
  */
 mPaint.reset();
 mPaint.setAntiAlias(true);
 mPaint.setColor(mTextColor);
 mPaint.setTextSize(mTextSize);
 mPaint.getTextBounds(mContent, 0, mContent.length(), mBounds);
 canvas.drawText(mContent, xPoint - mBounds.width() / 2, xPoint + mBounds.height() / 2, mPaint);
 }
}

4.在xml文件中申明我们的自定义View

好了，这样就完成了我们的水平加载进度条，和圆形加载进度条效果了，是不是感觉还可以啊。

源码下载地址

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。