Android Drawable的用法

Android 2D 绘图--------Drawable类的用法

一． 从项目资源来创建图像

1. Java程序代码内使用方法建立窗体布局

代码：

public class MDrawableActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

LinearLayout mLinearLayout = new LinearLayout(this);

ImageView mImageView = new ImageView(this);

mImageView.setImageResource(R.drawable.baxinhua);

mImageView.setAdjustViewBounds(true);

mImageView.setLayoutParams(new

Gallery.LayoutParams(LayoutParams.WRAP_CONTENT,

LayoutParams.WRAP_CONTENT));

mLinearLayout.addView(mImageView);

setContentView(mLinearLayout);

}

}

2. 通过Resources 类来获得项目资源

Resources res = getResources();

Drawable drawable = res.getDrawable(R.drawable.xxx);

二． 从XML文件来定义图像

1) 可在XML文件定义的绘图子类

绘图子类 XML文件内的标签名称

AnimationDrawable(动画绘图)

BitmapDrawable(图像绘图)

ClipDrawble(剪切绘图)

ColorDrawable(色彩绘图)

GradientDrawable(斜度绘图)

InsetDrawable(插入绘图)

(层次绘图)

LevelListDrawable

RotateDrawable(旋转绘图)

ScaleDrawable(缩放绘图)

StateListDrawable

TransitionDrawable(过度绘图)

2)定义图像的xml文件（以TransitionDrawable为例）

xmlns:android=http://schemas.android.com/apk/res/android>

代码：

public class TransitionDrawableActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Resources res = getResources();

TransitionDrawable transition =

(TransitionDrawable)res.getDrawable(R.drawable.transition_image);

//图片自动从第一张慢慢淡化到第二张。

ImageView mImageView = (ImageView)findViewById(R.id.mImageView);

mImageView.setImageDrawable(transition);

transition.startTransition(5*1000);

}

}

2) 自定义View对象

public class MShapeDrawable extends View {

private ShapeDrawable mShapDrawable;

public MShapeDrawable(Context context) {

super(context);

int x = 10;

int y = 10;

int width = 300;

int height = 50;

mShapDrawable = new ShapeDrawable(new OvalShape());

mShapDrawable.getPaint().setColor(0xff74AC23);

mShapDrawable.setBounds(x ,y , x+width, y+height);

}

protected void onDraw(Canvas canvas) {

mShapDrawable.draw(canvas);

}

}

然后在Activity里面显示

public class ShapDrawableActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState){

super.onCreate(savedInstanceState);

MShapeDrawable mShapDrawable = new MShapeDrawable(this);

setContentView(mShapDrawable);

}

}