Android 自定义View修炼-自定义加载进度动画XCLoadingImageView

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

private Paint mImagePaint;
    private int mImageHeight, mImageWidth;
    private boolean mIsAutoStart = false;
    private int mMaskColor = Color.TRANSPARENT;
    private ClipDrawable mClipDrawable;
    private Drawable mMaskDrawable;
    private int maskHeight;
    private int mProgress;
    private ObjectAnimator mAnimator;
    private long mAnimDuration = 2500;
    private float mScaleX, mScaleY;
    private int mGravity = Gravity.BOTTOM;
    private int mOrientaion = ClipDrawable.VERTICAL;
    private int mMaskOrientation = MaskOrientation.BottomToTop;

    //Loading oriention
    public static final class MaskOrientation {
        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 void initAttrs(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 void init() {
        if (mImagePaint == null) {
            mImagePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            mImagePaint.setXfermode(new PorterDuffXfermode(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

源码下载：http://www.demodashi.com/demo/13442.html

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