一、概述

本自定义View，是加载进度动画的自定义View，继承于ImageView来实现，主要实现蒙层加载进度的加载进度效果。

支持水平左右加载和垂直上下加载四个方向，同时也支持自定义蒙层进度颜色。

直接看下面的效果图吧。

二、效果图

废话不说，先来看看效果图吧~~

三、实现原理方案

1、自定义View-XCLoadingImageView，继承ImageVIew来实现，这样就不用自己再处理drawable和测量的工作内容。

2、根据蒙层颜色创建一个蒙层bitmap，然后根据这个bitmap来创建一个ClipDrawable，最后利用ClipDrawable的level属性

来裁剪显示区域进度，从而达到加载进度的效果。

3、最后利用属性动画技术或ClipDrawable的setLevel()方法来达到进度的效果。

四、自定义加载进度效果XCLoadingImageView的具体实现

1、初始化需要用到的数据变量以及画笔以及属性

privatePaint mImagePaint;private intmImageHeight, mImageWidth;private boolean mIsAutoStart = false;private int mMaskColor =Color.TRANSPARENT;privateClipDrawable mClipDrawable;privateDrawable mMaskDrawable;private intmaskHeight;private intmProgress;privateObjectAnimator mAnimator;private long mAnimDuration = 2500;private floatmScaleX, mScaleY;private int mGravity =Gravity.BOTTOM;private int mOrientaion =ClipDrawable.VERTICAL;private int mMaskOrientation =MaskOrientation.BottomToTop;//Loading oriention

public static final classMaskOrientation {public static final int LeftToRight = 1;public static final int RightToLeft = 2;public static final int TopToBottom = 3;public static final int BottomToTop = 4;

}/*** initial attributes*/

private voidinitAttrs(Context context, AttributeSet attrs) {if (attrs == null) {return;

}

TypedArray t=context.obtainStyledAttributes(attrs, R.styleable.XCLoadingImageView);

mMaskColor=t.getColor(R.styleable.XCLoadingImageView_mask_color, mMaskColor);

mIsAutoStart=t.getBoolean(R.styleable.XCLoadingImageView_auto_start_anim, mIsAutoStart);

setMaskColor(mMaskColor);

t.recycle();

}/*** initial paint*/

private voidinit() {if (mImagePaint == null) {

mImagePaint= newPaint(Paint.ANTI_ALIAS_FLAG);

mImagePaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));

}

}

2、初始化蒙层Bitmap以及创建加载进度用的ClipDrawable

private void initMaskBitmap(int maskColor) {

Drawable drawable = getDrawable();

if (drawable == null) {

return;

}

Bitmap bgBmp = ((BitmapDrawable) drawable).getBitmap();

mImageWidth = drawable.getIntrinsicWidth();

mImageHeight = drawable.getIntrinsicHeight();

Bitmap fgBmp = Bitmap.createBitmap(mImageWidth, mImageHeight, Bitmap.Config.ARGB_8888);

Canvas fgCanvas = new Canvas(fgBmp);

fgCanvas.drawColor(maskColor);

Bitmap bitmap = combineBitmap(bgBmp, fgBmp);

mMaskDrawable = new BitmapDrawable(null, bitmap);

mClipDrawable = new ClipDrawable(mMaskDrawable, mGravity, mOrientaion);

}

3、合并蒙层Bitmap和ImageView的src的drawable为新的Bitmap

/**

* combine tow bitmap to one bitmap

*/

private Bitmap combineBitmap(Bitmap bg, Bitmap fg) {

Bitmap bmp = Bitmap.createBitmap(mImageWidth, mImageHeight, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(bmp);

canvas.drawBitmap(bg, 0, 0, null);

canvas.drawBitmap(fg, 0, 0, mImagePaint);

return bmp;

}

4、重写ImageVIew的onDraw()方法来把创建的ClipDrawable绘制到Canvas上

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

canvas.save();

canvas.scale(mScaleX, mScaleY);

mClipDrawable.setBounds(getDrawable().getBounds());

mClipDrawable.draw(canvas);

canvas.restore();

}

5、弹通过属性动画或者setLevel，并调用postInvalidate()来重绘，从而达到进度刷新的效果

private void initAnim() {

stopAnim();

mAnimator = ObjectAnimator.ofInt(mClipDrawable, "level", 0, 10000);

mAnimator.setDuration(mAnimDuration);

mAnimator.setRepeatCount(ValueAnimator.INFINITE);

mAnimator.setRepeatMode(ValueAnimator.RESTART);

mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

postInvalidate();

}

});

if (mIsAutoStart) {

mAnimator.start();

}

}

public void setProgress(int progress){

mProgress = progress;

mClipDrawable.setLevel(mProgress * 100);

postInvalidate();

}

五、如何使用该自定义LoadingView控件

1、使用该自定义LoadingView非常简单，和使用普通ImageView差不对哦，只需设置下方向和蒙层颜色即可

public class MainActivity extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

XCLoadingImageView imageView2 = (XCLoadingImageView) findViewById(R.id.img2);

imageView2.setMaskOrientation(XCLoadingImageView.MaskOrientation.LeftToRight);

imageView2.setProgress(50);

}

}

六、源码下载

原文：http://www.cnblogs.com/JczmDeveloper/p/5037068.html