Android那些事儿之自定义进度条
Android原生控件只有横向进度条一种，而且没法变换样式，比如原生rom的样子
很丑是吧，当伟大的产品设计要求更换前背景，甚至纵向，甚至圆弧状的，咋办，比如
ok，我们开始吧：
一）变换前背景
先来看看progressbar的属性：
<ProgressBar android:id="@+id/progressBar" style="?android:attr/progressBarStyleHorizontal" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="5dip" android:layout_toRightOf="@+id/progressBarV" android:indeterminate="false" android:padding="2dip" android:progress="50" />
根据style="?android:attr/progressBarStyleHorizontal"，我们找到源码中的style.xml
<style name="Widget.ProgressBar.Horizontal"> <item name="android:indeterminateOnly">false</item> <item name="android:progressDrawable">@android:drawable/progress_horizontal</item> <item name="android:indeterminateDrawable">@android:drawable/progress_indeterminate_horizontal</item> <item name="android:minHeight">20dip</item> <item name="android:maxHeight">20dip</item> </style>
看到
<item name="android:progressDrawable">@android:drawable/progress_horizontal</item>
木有，继续发掘源码，找到drawable下面的progress_horizontal.xml，这就是我们今天的主角了：
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"> <item android:id="@android:id/background"> <shape> <corners android:radius="5dip" /> <gradient android:startColor="#ff9d9e9d" android:centerColor="#ff5a5d5a" android:centerY="0.75" android:endColor="#ff747674" android:angle="270" /> </shape> </item> <item android:id="@android:id/secondaryProgress"> <clip> <shape> <corners android:radius="5dip" /> <gradient android:startColor="#80ffd300" android:centerColor="#80ffb600" android:centerY="0.75" android:endColor="#a0ffcb00" android:angle="270" /> </shape> </clip> </item> <item android:id="@android:id/progress"> <clip> <shape> <corners android:radius="5dip" /> <gradient android:startColor="#ffffd300" android:centerColor="#ffffb600" android:centerY="0.75" android:endColor="#ffffcb00" android:angle="270" /> </shape> </clip> </item> </layer-list>
看到android:id="@android:id/progress"木有，看到android:id="@android:id/secondaryProgress"木有
把这个文件复制到自己工程下的drawable，就可以随心所欲的修改shape的属性，渐变，圆角等等
那么怎么放一个图片进去呢，ok，新建progress_horizontal1.xml：
<?xml version="1.0" encoding="utf-8"?> <layer-list xmlns:android="http://schemas.android.com/apk/res/android"> <item android:id="@android:id/progress" android:drawable="@drawable/progressbar" /> </layer-list>
在android:drawable中指定你处理好的图片
然后回到布局中
<ProgressBar android:id="@+id/progressBar1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/progressBar" android:layout_margin="5dip" android:layout_toRightOf="@+id/progressBarV" android:background="@drawable/progress_bg" android:indeterminate="false" android:indeterminateOnly="false" android:maxHeight="20dip" android:minHeight="20dip" android:padding="2dip" android:progress="50" android:progressDrawable="@drawable/progress_horizontal1" />
android:background="@drawable/progress_bg"指定背景
android:progressDrawable="@drawable/progress_horizontal1"前景使用上面的progress_horizontal1
ok，搞定
注意看，四角还是有圆倒角的，貌似是系统自己加上去的，总之我的图片里面是没有做这个倒角处理的
二）纵向进度条
还是得从源码入手，看回progress_horizontal.xml
<item android:id="@android:id/progress"> <clip> <shape> <corners android:radius="5dip" /> <gradient android:startColor="#ffffd300" android:centerColor="#ffffb600" android:centerY="0.75" android:endColor="#ffffcb00" android:angle="270" /> </shape> </clip> </item>
为什么shape外面要包一层clip呢，官方文档解释是clipdrawable是可以自我复制的，来看看定义
<?xml version="1.0" encoding="utf-8"?> <clip xmlns:android="http://schemas.android.com/apk/res/android" android:drawable="@drawable/drawable_resource" android:clipOrientation=["horizontal" | "vertical"] android:gravity=["top" | "bottom" | "left" | "right" | "center_vertical" | "fill_vertical" | "center_horizontal" | "fill_horizontal" | "center" | "fill" | "clip_vertical" | "clip_horizontal"] />
android:clipOrientation有两个属性，默认为horizontal
android:gravity有两个属性，默认为left
那我们试试改成vertical和bottom会有什么效果，新建一个progress_vertical.xml，把源码progress_horizontal.xml的内容复制过来，这里去掉了secondaryProgress，修改了clip，shape的渐变中心centerY改为centerX
<item android:id="@android:id/progress"> <clip android:clipOrientation="vertical" android:gravity = "bottom"> <shape> <corners android:radius="5dip" /> <gradient android:startColor="#ffffd300" android:centerColor="#ffffb600" android:centerX="0.75" android:endColor="#ffffcb00" android:angle="90" /> </shape> </clip> </item>
布局中android:progressDrawable="@drawable/progress_vertical"
ok，搞定，就是这么简单：
三）弧形bar
这个也许算不上是进度条，用的也不多，最多也就仪表盘用用，不然谁会把进度条整成圆弧的呢。好吧这个可不是改改源码就能搞定的，看代码
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public class Arcs extends View { private Paint mArcPaint; private Paint mArcBGPaint; private RectF mOval; private float mSweep = 0; private int mSpeedMax = 200; private int mThreshold = 100; private int mIncSpeedValue = 0; private int mCurrentSpeedValue = 0; private float mCenterX; private float mCenterY; private float mSpeedArcWidth; private final float SPEED_VALUE_INC = 2; .......... }
首先是一堆成员变量，两个Paint用来画圆弧一个前景一个背景，一个RectF圆弧就画在上面，然后是一些控制参数比如sweep圆弧扫过的角度，xy坐标等等
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mArcPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mArcPaint.setStyle(Paint.Style.STROKE); mArcPaint.setStrokeWidth(mSpeedArcWidth); // mPaint.setStrokeCap(Paint.Cap.ROUND); mArcPaint.setColor(0xff81ccd6); BlurMaskFilter mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.INNER); mArcPaint.setMaskFilter(mBlur); mArcBGPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mArcBGPaint.setStyle(Paint.Style.STROKE); mArcBGPaint.setStrokeWidth(mSpeedArcWidth+8); mArcBGPaint.setColor(0xff171717); BlurMaskFilter mBGBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.INNER); mArcBGPaint.setMaskFilter(mBGBlur);
设置两个画笔，颜色，宽度，样式等等，BlurMaskFilter笔是边缘模糊效果，有几种，可以自己尝试
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@Override protected void onSizeChanged(int w, int h, int ow, int oh) { super.onSizeChanged(w, h, ow, oh); Log.i("onSizeChanged w", w+""); Log.i("onSizeChanged h", h+""); mCenterX = w * 0.5f; // remember the center of the screen mCenterY = h - mSpeedArcWidth; mOval = new RectF(mCenterX - mCenterY, mSpeedArcWidth, mCenterX + mCenterY, mCenterY * 2); }
重写父类View的onSizeChanged，为的是自己根据布局中的大小做居中处理
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@Override protected void onDraw(Canvas canvas) { drawSpeed(canvas); calcSpeed(); } private void drawSpeed(Canvas canvas) { canvas.drawArc(mOval, 179, 181, false, mArcBGPaint); mSweep = (float) mIncSpeedValue / mSpeedMax * 180; if (mIncSpeedValue > mThreshold) { mArcPaint.setColor(0xFFFF0000); } else { mArcPaint.setColor(0xFF00B0F0); } canvas.drawArc(mOval, 180, mSweep, false, mArcPaint); } private void calcSpeed() { if (mIncSpeedValue < mCurrentSpeedValue) { mIncSpeedValue += SPEED_VALUE_INC; if (mIncSpeedValue > mCurrentSpeedValue) { mIncSpeedValue = mCurrentSpeedValue; } invalidate(); } else if (mIncSpeedValue > mCurrentSpeedValue) { mIncSpeedValue -= SPEED_VALUE_INC; if (mIncSpeedValue < mCurrentSpeedValue) { mIncSpeedValue = mCurrentSpeedValue; } invalidate(); } }
重写onDraw以便重绘canvas
drawSpeed里面
通过计算mSweep = (float) mIncSpeedValue / mSpeedMax * 180;
然后canvas.drawArc(mOval, 180, mSweep, false, mArcPaint);
会根据mSweep的变化，画出相应长度的弧度来
根据与阈值的对比，还可以设定不同的 颜色：
if (mIncSpeedValue > mThreshold) { mArcPaint.setColor(0xFFFF0000); } else { mArcPaint.setColor(0xFF00B0F0); }
calcSpeed通过一个步进来控制增量或减量，以使弧度自然过渡，减少跳跃
ok，大功告成
