由于個人喜好， 比較喜歡iOS 原生的東西，現(xiàn)在學習Android開發(fā)，可能有先入為主的思想吧，所以總想在Andorid中找與iOS相同的控件。

在使用活動指示器的時候，發(fā)現(xiàn)Android的是ProgressBar，動畫的方式與iOS的不一樣，一直都想弄一個一樣的。

我自己比較喜歡自定義View，不是太喜歡GIF，雖然GIF方便，但學習嘛，空余時間多讓腦筋轉(zhuǎn)轉(zhuǎn)動動手也好。

這里就自定義一個iOS “菊花”式的活動指示器，

詳細代碼如下：

UIAcivityIndicatorView.java

import?android.content.Context;
import?android.content.res.TypedArray;
import?android.graphics.Canvas;
import?android.graphics.Color;
import?android.graphics.Paint;
import?android.os.Handler;
import?android.util.AttributeSet;
import?android.view.View;

/**
?*?Created?by?wantao?on?17/1/7.
?*/
public?class?UIActivityIndicatorView?extends?View?{
????public?UIActivityIndicatorView(Context?context)?{
????????this(context,?null);
????}

????private?int?startColor?=?Color.argb(255,?255,?255,?255);
????private?float?strokeWidth?=?0;
????private?int?startAngle?=?0;

????public?UIActivityIndicatorView(Context?context,?AttributeSet?attrs)?{
????????super(context,?attrs);

????????TypedArray?typedArray?=?context.obtainStyledAttributes(attrs,?R.styleable.UIActivityIndicatorView);
????????for?(int?i?=?0;?i?<?typedArray.getIndexCount();?i++)?{
????????????int?i1?=?typedArray.getIndex(i);
????????????if?(i1?==?R.styleable.UIActivityIndicatorView_AIV_startColor)?{
????????????????startColor?=?typedArray.getColor(R.styleable.UIActivityIndicatorView_AIV_startColor,?startColor);

????????????}?else?if?(i1?==?R.styleable.UIActivityIndicatorView_AIV_startAngle)?{
????????????????startAngle?=?typedArray.getInt(R.styleable.UIActivityIndicatorView_AIV_startAngle,?startAngle);

????????????}?else?if?(i1?==?R.styleable.UIActivityIndicatorView_AIV_strokeWidth)?{
????????????????strokeWidth?=?typedArray.getDimension(R.styleable.UIActivityIndicatorView_AIV_strokeWidth,?strokeWidth);

????????????}
????????}

????????initialize();
????}

????private?final?int?LineCount?=?12;
????private?final?int?MinAlpha?=?0;
????private?final?int?AngleGradient?=?360?/?LineCount;
????private?Paint?paint;
????private?int[]?colors?=?new?int[LineCount];
????private?void?initialize()?{
????????paint?=?new?Paint(Paint.ANTI_ALIAS_FLAG);
????????int?alpha?=?Color.alpha(startColor);
????????int?red?=?Color.red(startColor);
????????int?green?=?Color.green(startColor);
????????int?blue?=?Color.blue(startColor);
????????int?alpha_gradient?=?Math.abs(alpha?-?MinAlpha)?/?LineCount;
????????for?(int?i?=?0;?i?<?colors.length;?i++)?{
????????????colors[i]?=?Color.argb(alpha?-?alpha_gradient?*?i,?red,?green,?blue);
????????}
????????paint.setStrokeCap(Paint.Cap.ROUND);
????}

????@Override
????protected?void?onDraw(Canvas?canvas)?{
????????super.onDraw(canvas);
????????int?centerX?=?getWidth()/2;
????????int?centerY?=?getHeight()/2;
????????float?radius?=?Math.min(getWidth()-getPaddingLeft()-getPaddingRight(),?getHeight()-getPaddingTop()-getPaddingBottom())?*?0.5f;
????????if?(strokeWidth?==?0)?strokeWidth?=?pointX(AngleGradient/2,?radius/2)/2;
????????paint.setStrokeWidth(strokeWidth);
????????for?(int?i?=?0;?i?<?colors.length;?i++)?{
????????????paint.setColor(colors[i]);
????????????canvas.drawLine(
????????????????????centerX?+?pointX(-AngleGradient*i?+?startAngle,?radius/2),
????????????????????centerY?+?pointY(-AngleGradient*i?+?startAngle,?radius/2),
????????????????????centerX?+?pointX(-AngleGradient*i?+?startAngle,?radius?-?strokeWidth/2),???//??這里計算Y值時,?之所以減去線寬/2,?是防止沒有設置的Padding時,圖像會超出View范圍
????????????????????centerY?+?pointY(-AngleGradient*i?+?startAngle,?radius?-?strokeWidth/2),???//??這里計算Y值時,?之所以減去線寬/2,?是防止沒有設置的Padding時,圖像會超出View范圍
????????????????????paint);
????????}
????}

????private?float?pointX(int?angle,?float?radius)?{
????????return?(float)?(radius?*?Math.cos(angle?*?Math.PI?/?180));
????}

????private?float?pointY(int?angle,?float?radius)?{
????????return?(float)?(radius?*?Math.sin(angle?*?Math.PI?/?180));
????}

????private?Handler?animHandler?=?new?Handler();
????private?Runnable?animRunnable?=?new?Runnable()?{
????????@Override
????????public?void?run()?{
????????????startAngle?+=?AngleGradient;
????????????invalidate();
????????????animHandler.postDelayed(animRunnable,?50);
????????}
????};

????public?void?start()?{
????????animHandler.post(animRunnable);
????}

????public?void?stop()?{
????????animHandler.removeCallbacks(animRunnable);
????}

????public?void?setStartColor(int?startColor)?{
????????this.startColor?=?startColor;
????}

????public?void?setStrokeWidth(float?strokeWidth)?{
????????this.strokeWidth?=?strokeWidth;
????}

????public?void?setStartAngle(int?startAngle)?{
????????this.startAngle?=?startAngle;
????}
}

自定義xml屬性文件， app→res→values→attrs.xml(這個xml文件沒有的話，自己新建一個)內(nèi)添加內(nèi)容如下：

另外，我還打包了一個“.aar”包，導入項目后可直接使用。

文件地址，還沒有審核通過，等通過后再更新，或者可以到我的資源頁查看。

對于怎么導入“.aar”包到項目，這里簡單介紹，【針對Android Studio(因為我也剛學習Andorid，只用過Android Studio)】:

1. 將需要的.aar文件拷貝到Project的app→libs中； 2. 修改build.grade(Module:app): 添加?

repositories?{
	flatDir?{
		dirs?'libs'
	}
}

然后在下面的dependencies(){}中添加

compile(name:'(.aar文件名)',?ext:'aar')