# 常用控件

## CircularBar - 圆形进度条

CircularBar是一个特殊动画的圆形进度条, 常用于提示用户等待网络/io等结果. 效果如下:

![CircularBar](/files/-LsLm8FuOm5hcpuWA539)

CircularBar的用法很简单, 有3个可配置选项:

```
<declare-styleable name="CircularBar">
    <attr name="circularColor" format="color" /> // 圆弧颜色
    <attr name="circularBackgroundColor" format="color" /> // 圆弧背景色
    <attr name="circularWidth" format="dimension" /> // 圆弧宽度
</declare-styleable>
```

```
<com.corelibs.views.CircularBar
    android:layout_width="100dp"
    android:layout_height="100dp"
    app:circularWidth="5dp"
    app:circularBackgroundColor="#ccc"
    app:circularColor="#FFFF0000"/>
```

也可通过代码设置:

```
bar.setFrontColor(0xFFFF0000)
bar.setStrokeWidth(DisplayUtil.dip2px(context, 5));
bar.setBackgroundColor(0xFFCCCCCC)
```

需要注意的是, 默认情况下, 无需对CircularBar做任何处理, 甚至无需在java里将其声明出来. 但是如果一旦要反复的控制CircularBar的显示隐藏, 就需要调用CircularBar的`startAnimation()`和`stopAnimation()`来控制动画的启动与停止. 这是为什么呢? 由于CircularBar内部使用的是ObjectAnimator, 并且是反转的无限动画. 无限动画如果不在适当的时候停止动画, 很容易造成context的内存泄漏. CircularBar会在`onAttachedToWindow()`中启动动画, `onDetachedFromWindow()`中停止动画, 因此大部分情况下无需处理动画的停止.

## LoadingDialog - BaseActivity中默认的加载框

LoadingDialog是BaseActivity中默认的加载框, 长得跟下面一样:

![LoadingDialog](/files/-LsLm8FwUkzACiu-TOmd)![LoadingDialog1](/files/-LsLm8FyKKMMFqhTlEsL)![LoadingDialog2](/files/-LsLm8G-zWs7l6BAMTnm)

LoadingDialog默认是没有文字的, 可以通过`loadingDialog.setMessage()`来设置String或者resource的文字消息. 可以看到LoadingDialog中使用了CircularBar, LoadingDialog对CircularBar的动画做了以处理避免内存泄漏的发生. 使用方法:

```
LoadingDialog loadingDialog = new LoadingDialog(this);
// LoadingDialog loadingDialog = new LoadingDialog(this, R.string.hint);

loadingDialog.setMessage(R.string.hint);

loadingDialog.show();
loadingDialog.dismiss();
```

## MaterialDialog - Material风格的对话框

项目中推荐默认使用MaterialDialog, 而无需跟着UI设计自己编写一个Dialog, 重复工作太多. MaterialDialog的用法比较简单, 支持的布局也很多, 具体可以参考 [GitHub](https://github.com/afollestad/material-dialogs) .


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