Android基础之UI设计与开发---------自定义进度条

一、在开发中我们经常要用到进度条显示下载或者加载的进度。系统自带的黄色进度条在UI效果上经常不能满足策划或者美工的要求。这就要我们屌丝程序员自己自定义进度条。

话不多说，先上图。



        实现步骤一：先定义进度条的风格样式

                              

<!-- 自定义进度条 -->
<style name="ProgressBar_Mini" parent="@android:style/Widget.ProgressBar.Horizontal">
<item name="android:maxHeight">50dip</item>
<item name="android:minHeight">8dip</item>
<item name="android:indeterminateOnly">false</item>
<item name="android:indeterminateDrawable">@android:drawable/progress_indeterminate_horizontal</item>
<item name="android:progressDrawable">@drawable/progressbar_mini</item>
</style>

       实现步骤二：定义样式style中用到的@drawable/progressbar_mini资源文件。可以再xml中绘制进度条的不同样式（圆角，直角……）和颜色。

            

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:id="@android:id/background">
<shape >
<corners android:radius="5dip" />
<gradient
android:angle="270"
android:centerY="0.75"
android:endColor="#F5F5F5"
android:startColor="#BEBEBE" />
</shape>
</item>

<item android:id="@android:id/secondaryProgress">

<clip >
<shape >
<corners android:radius="0dip" />
<gradient
android:angle="270"
android:centerY="0.75"
android:endColor="#165CBC"
android:startColor="#85B0E9" />
</shape>
</clip>
</item>

<item android:id="@android:id/progress">

<clip >
<shape >
<corners android:radius="5dip" />
<gradient
android:angle="270"
android:centerY="0.75"
android:endColor="#165CBC"
android:startColor="#85B0E9" />
</shape>

</clip>
</item>
</layer-list>

          实现步骤三：写java文件，定义进度条上显示的文字。

public class MyProgressBar extends ProgressBar {
private String text_progress;
private Paint mPaint;//画笔

public MyProgressBar(Context context) {
super(context);
initPaint();
}
public MyProgressBar(Context context, AttributeSet attrs) {
super(context, attrs);
initPaint();
}
public MyProgressBar(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initPaint();
}

@Override
public synchronized void setProgress(int progress) {
super.setProgress(progress);
setTextProgress(progress);
}
@Override
protected synchronized void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
Rect rect=new Rect();
this.mPaint.getTextBounds(this.text_progress, 0, this.text_progress.length(), rect);
int x = (getWidth() / 2) - rect.centerX();
int y = (getHeight() / 2) - rect.centerY();
canvas.drawText(this.text_progress, x, y, this.mPaint);
}
/**
*
*description: 初始化画笔
*Create by lll on 2013-8-13 下午1:41:49
*/
private void initPaint(){
this.mPaint=new Paint();
this.mPaint.setAntiAlias(true);
this.mPaint.setColor(Color.WHITE);
}
private void setTextProgress(int progress){
int i = (int) ((progress * 1.0f / this.getMax()) * 100);
this.text_progress = String.valueOf(i) + "%";
}

}

       最后一步：xml文件中引用自定义的进度条：

     

<com.example.widgetshop.MyProgressBar
android:id="@+id/progressBar1"
style="@style/ProgressBar_Mini"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:progress="100"
android:layout_marginTop="24dp" />

OK,一个简单的更改背景和样式其带文字显示的进度条就完成。