Android中Drawable小结
Drawabe是可绘制到屏幕上图形一种概述，屏幕上绘制的图形内容都会最终已Drawable形式提供，Drawable提供了多种展示形式，如下：
Bitmap: the simplest Drawable, a PNG or JPEG or,GIF image. -->BitmapDrawable
Nine Patch: an extension to the PNG format allows it to specify information about how to stretch it and place things inside of it. -->NinePatchDrawable
Shape: contains simple drawing commands instead of a raw bitmap, allowing it to resize better in some cases. -->ShapeDrawable xml<shape>
Layers: a compound drawable, which draws multiple underlying drawables on top of each other. -->LayerDrawable xml<layer-list>
States: a compound drawable that selects one of a set of drawables based on its state. -->StateListDrawable xml<selector>
Levels: a compound drawable that selects one of a set of drawables based on its level. -->LevelListDrawable xml<level-list>
Scale: a compound drawable with a single child drawable, whose overall size is modified based on the current level. -->ScaleDrawable xml<scale>
XML Bitmap：使用xml方式处理Bitmap,例如小图平铺背景
xml定义
<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
android:src="@drawable/icon"
android:tileMode="repeat" />
titleMode为Bitmap重复填充方式，tileMode="clamp"填充边缘色
XML Nine-Patch：
<?xml version="1.0" encoding="utf-8"?>
<nine-patch
xmlns:android="http://schemas.android.com/apk/res/android"
android:src="@[package:]drawable/drawable_resource"
android:dither=["true" | "false"] />
LayerDrawable：管理一组drawable显示处理，例如：叠加图形的展示
xml定义：
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<bitmap android:src="@drawable/android_red"
android:gravity="center" />
</item>
<item android:top="10dp" android:left="10dp">
<bitmap android:src="@drawable/android_green"
android:gravity="center" />
</item>
<item android:top="20dp" android:left="20dp">
<bitmap android:src="@drawable/android_blue"
android:gravity="center" />
</item>
</layer-list>
layer-list阴影效果：
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!--底层阴影-->
<!--top代表下边的阴影高度，left代表右边的阴影宽度 如果不做这个控制，底层和上层的左上会重合在一起-->
<item
android:left="2dp"
android:top="2dp">
<shape android:shape="rectangle">
<!--使用渐变色处理阴影色度 angle 0 左边；90 下边，180，右边，270 上边-->
<gradient
android:angle="270"
android:endColor="#0F000000"
android:startColor="#0F000000"/>
<corners
android:radius="8dp"/>
</shape>
</item>
<!-- 上层背景部分 上层的右边距离底层的右边3,距离底层底部3dp-->
<item
android:bottom="3dp"
android:right="3dp">
<shape android:shape="rectangle">
<corners android:radius="8dp"/>
</shape>
</item>
</layer-list>
可参考：https://blog.csdn.net/android_cmos/article/details/80033784
StateListDrawable:根据View的状态来展示不同状态下的Drawable
xml文件:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true"
android:drawable="@drawable/button_pressed" /> <!-- pressed -->
<item android:state_focused="true"
android:drawable="@drawable/button_focused" /> <!-- focused -->
<item android:state_hovered="true"
android:drawable="@drawable/button_focused" /> <!-- hovered -->
<item android:drawable="@drawable/button_normal" /> <!-- default -->
</selector>
LevelListDrawable:展示几张图形，使用setLevel() or setImageLevel()来展示不同Drawable
xml定义:
<?xml version="1.0" encoding="utf-8"?>
<level-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:drawable="@drawable/status_off"
android:maxLevel="0" />
<item
android:drawable="@drawable/status_on"
android:maxLevel="1" />
</level-list>
TransitionDrawable:限制两个Drawable,淡入淡出效果过度展示
xml定义:
<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/on" />
<item android:drawable="@drawable/off" />
</transition>
使用:
ImageButton button = (ImageButton) findViewById(R.id.button); TransitionDrawable drawable = (TransitionDrawable) button.getDrawable(); drawable.startTransition(500);
InsetDrawable：嵌入到另一个Drawable里，指定边距区域显示，例如：背景区域小于内容区可使用
xml文件:
<?xml version="1.0" encoding="utf-8"?>
<inset
xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/drawable_resource"
android:insetTop="dimension"
android:insetRight="dimension"
android:insetBottom="dimension"
android:insetLeft="dimension" />
ScaleDrawable:对Drawable的尺寸进行拉伸处理
xml定义:
<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/logo"
android:scaleGravity="center_vertical|center_horizontal"
android:scaleHeight="80%"
android:scaleWidth="80%" />
ClipDrawable：裁剪处理
<?xml version="1.0" encoding="utf-8"?>
<clip xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/android"
android:clipOrientation="horizontal"
android:gravity="left" />
/**
* Drawable转化为Bitmap
*/
public static Bitmap drawableToBitmap(Drawable drawable) {
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(width, height, drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, width, height);
drawable.draw(canvas);
return bitmap;
}
/**
* Bitmap to Drawable
* @param bitmap
* @param mcontext
* @return
*/
public static Drawable bitmapToDrawble(Bitmap bitmap,Context mcontext){
Drawable drawable = new BitmapDrawable(mcontext.getResources(), bitmap);
return drawable;
}
