ProgressBar 控件codeRead

ProgressBar sequence:

1:ProgressBar.java

1)指定attribute類型
      this(context, attrs, com.android.internal.R.attr.progressBarStyle);
      Attrs.xml---定義progressbar的Style屬性
        <attr name="progressBarStyle" format="reference" />
        <attr name="progressBarStyleHorizontal" format="reference" />
        <attr name="progressBarStyleSmall" format="reference" />
        <attr name="progressBarStyleSmallTitle" format="reference" />
        <attr name="progressBarStyleLarge" format="reference" />
        <attr name="progressBarStyleInverse" format="reference" />
        <attr name="progressBarStyleSmallInverse" format="reference" />
        <attr name="progressBarStyleLargeInverse" format="reference" />

2)obtainStyledAttributes(attrs, R.styleable.ProgressBar, defStyle, styleRes);
    Attrs.xml---定義progressbar的專有屬性
      <declare-styleable name="ProgressBar">
        <attr name="max" format="integer" />
        <attr name="progress" format="integer" />
        <attr name="secondaryProgress" format="integer" />
        <attr name="indeterminate" format="boolean" />
        <attr name="indeterminateOnly" format="boolean" />
        <attr name="indeterminateDrawable" format="reference" />
        <attr name="progressDrawable" format="reference" />
        <attr name="indeterminateDuration" format="integer" min="1" />
        <attr name="indeterminateBehavior">
            <enum name="repeat" value="1" />
            <enum name="cycle" value="2" />
        </attr>
        <attr name="minWidth" format="dimension" />
        <attr name="maxWidth" />
        <attr name="minHeight" format="dimension" />
        <attr name="maxHeight" />
        <attr name="interpolator" format="reference" />
        <attr name="animationResolution" format="integer" />
      </declare-styleable>
     
      通過Theme等對屬性賦值
      Theme.xml---<item name="progressBarStyle">@android:style/Widget.ProgressBar</item>
      Styles.xml----  
          <style name="Widget.ProgressBar">
          <item name="android:indeterminateOnly">true</item>
          <item name="android:indeterminateDrawable">@android:drawable/progress_medium_white</item>
          <item name="android:indeterminateBehavior">repeat</item>
          <item name="android:indeterminateDuration">3500</item>
          <item name="android:minWidth">48dip</item>
          <item name="android:maxWidth">48dip</item>
          <item name="android:minHeight">48dip</item>
          <item name="android:maxHeight">48dip</item>
       </style>

3)通過get的attribute進行處理
  其中對圖像的progressDrawable
  在horizontal中
      <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>
  @android:drawable/progress_horizontal
  進入frameworks/base/core/res/res/drawable/progress_horizontal.xml,裏面是對graphic屬性的設置

  <layer-list xmlns:android=http://schemas.android.com/apk/res/android>
    <item android:id="@android:id/background">--------------這個id是ProgressBar.java中用的
        <shape>//開始對background層的處理
            <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">--------------這個id是ProgressBar.java中用的
        <clip>//開始對background層的處理
            <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>
  </layerlist>
  其中：layer-list gradient clip等屬性是graphic中處理的：frameworks/base/graphics/java/android/graphics/drawable
 
  Tips:
  大部分的改動是針對graphics,drawable的
  看空間裏面的頭文件的定義來理解
----eg：progressbar
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.Shader;

import android.graphics.drawable.Animatable;
import android.graphics.drawable.AnimationDrawable;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ClipDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.LayerDrawable;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.StateListDrawable;
import android.graphics.drawable.shapes.RoundRectShape;
import android.graphics.drawable.shapes.