圖像級別組件以及如何實現圖像的半透明效果(自定義屬性)

圖像級別組件

<?xml version="1.0" encoding="utf-8"?>
<level-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item
        android:drawable="@drawable/bottle_pick_bg_spotlight_day"
        android:maxLevel="10"
        android:minLevel="6"/>
    <item
        android:drawable="@drawable/bottle_pick_bg_spotlight_night"
        android:maxLevel="20"
        android:minLevel="12"/>
</level-list>

代碼調用ImageView.setImageLevel(15);

 實現圖像的半透明效果

代碼:

1.attrs.xml

 

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="abc">
        <attr name="RID" format="integer" />
        <attr name="ALPHA" format="integer" />
    </declare-styleable>

</resources>

2.main.xml

 

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:cyx="http://schemas.android.com/apk/res/com.b.a"  //注意是程序包名
     android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <com.b.a.ImageViewExt
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        cyx:ALPHA="50"
        cyx:RID="0x7f020000" >
    </com.b.a.ImageViewExt>

</LinearLayout>

3.自定義類

public class ImageViewExt extends View {
 Bitmap bitmap;
 int alpha;

 public ImageViewExt(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.abc);
  int value = typedArray.getInt(R.styleable.abc_RID, 0);
  alpha = typedArray.getInt(R.styleable.abc_ALPHA, 0);
  typedArray.recycle();
  bitmap = BitmapFactory.decodeResource(getResources(), value);
  System.out.println();
 }

 public ImageViewExt(Context context, AttributeSet attrs) {
  super(context, attrs);
  TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.abc);
  int value = typedArray.getInt(R.styleable.abc_RID, 0);
  alpha = typedArray.getInt(R.styleable.abc_ALPHA, 0);
  typedArray.recycle();
  bitmap = BitmapFactory.decodeResource(getResources(), value);
  System.out.println();
 }

 public ImageViewExt(Context context) {
  super(context);
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  Paint paint = new Paint();
  paint.setAlpha(alpha);// 0-255來自於自定義的屬性
  // 繪製半透明的圖像
  canvas.drawBitmap(bitmap, new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()), new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()), paint);
 }

}

 

 

  

參考http://blog.csdn.net/longvslove/article/details/7084537