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。