一、加载bitmap 和 drawable
- 从asserts文件夹创建bitmap,并赋给imageview
AssetManager manager = getAssets();
// read a Bitmap from Assets
InputStream open = null;
try {
open = manager.open("logo.png");
Bitmap bitmap = BitmapFactory.decodeStream(open);
// Assign the bitmap to an ImageView in this layout
ImageView view = (ImageView) findViewById(R.id.imageView1);
view.setImageBitmap(bitmap);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (open != null) {
try {
open.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
- 从res/drawable 中获取drawable
Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.ic_action_search);
- 基于新的宽高尺寸获取bitmap
Bitmap originalBitmap =<initial setup> ;
Bitmap resizedBitmap =
Bitmap.createScaledBitmap(originalBitmap, newWidth, newHeight, false);
- 将bitmap转换为drawable
//Convert Bitmap to Drawable
Drawable d = new BitmapDrawable(getResources(),bitmap);
二、XML Drawable
- Sharp Drawable
<?xml version="1.0" encoding="UTF-8"?>
<shape
xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<stroke
android:width="2dp"
android:color="#FFFFFFFF" />
<gradient
android:endColor="#DDBBBBBB"
android:startColor="#DD777777"
android:angle="90" />
<corners
android:bottomRightRadius="7dp"
android:bottomLeftRadius="7dp"
android:topLeftRadius="7dp"
android:topRightRadius="7dp" />
</shape>
- State Drawable
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/button_pressed"
android:state_pressed="true" />
<item android:drawable="@drawable/button_checked"
android:state_checked="true" />
<item android:drawable="@drawable/button_default" />
</selector>
- transition Drawable
<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/first_image" />
<item android:drawable="@drawable/second_image" />
</transition>
final ImageView image = (ImageView) findViewById(R.id.image);
final ToggleButton button = (ToggleButton) findViewById(R.id.button);
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(final View v) {
TransitionDrawable drawable = (TransitionDrawable) image.getDrawable();
if (button.isChecked()) {
drawable.startTransition(500);
} else {
drawable.reverseTransition(500);
}
}
});
- Vector drawable
Android 5.0 开始可以定义Vector drawable ，优点是可以自动按比例缩放到设备的像素密度
<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:height="64dp"
android:width="64dp"
android:viewportHeight="600"
android:viewportWidth="600" >
<group
android:name="rotationGroup"
android:pivotX="300.0"
android:pivotY="300.0"
android:rotation="45.0" >
<path
android:name="v"
android:fillColor="#000000"
android:pathData="M300,70 l 0,-70 70,70 0,0 -70,70z" />
</group>
</vector>
- Animation Drawable
可以通过 setBackgroundResource()的方式给view设置animation drawable
<!-- Animation frames are phase*.png files inside the
res/drawable/ folder -->
<animation-list android:id="@+id/selected" android:oneshot="false">
<item android:drawable="@drawable/phase1" android:duration="400" />
<item android:drawable="@drawable/phase2" android:duration="400" />
<item android:drawable="@drawable/phase3" android:duration="400" />
</animation-list>
ImageView img = (ImageView)findViewById(R.id.yourid);
img.setBackgroundResource(R.drawable.your_animation_file);
// Get the AnimationDrawable object.
AnimationDrawable frameAnimation = (AnimationDrawable) img.getBackground();
// Start the animation (looped playback by default).
frameAnimation.start();
9 Patch drawable
自定义 drawable
创建custom Drawable类
package com.vogella.android.drawables.custom;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;
public class MyRoundCornerDrawable extends Drawable {
private Paint paint;
public MyRoundCornerDrawable(Bitmap bitmap) {
BitmapShader shader;
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP,
Shader.TileMode.CLAMP);
paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);
}
@Override
public void draw(Canvas canvas) {
int height = getBounds().height();
int width = getBounds().width();
RectF rect = new RectF(0.0f, 0.0f, width, height);
canvas.drawRoundRect(rect, 30, 30, paint);
}
@Override
public void setAlpha(int alpha) {
paint.setAlpha(alpha);
}
@Override
public void setColorFilter(ColorFilter cf) {
paint.setColorFilter(cf);
}
@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
}
在布局文件中使用
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<ImageView
android:id="@+id/image"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:contentDescription="TODO" />
</RelativeLayout>
package com.vogella.android.drawables.custom;
import java.io.InputStream;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ImageView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView button = (ImageView) findViewById(R.id.image);
InputStream resource = getResources().openRawResource(R.drawable.dog);
Bitmap bitmap = BitmapFactory.decodeStream(resource);
button.setBackground(new MyRoundCornerDrawable(bitmap));
}
}
