缩放图片 : matrix.setScale(0.5f,0.5f);
public
class
MainActivity
extends
Activity
implements
OnClickListener {
private
Button
bt
;
private
ImageView
iv
;
private
ImageView
iv_after
;
@Override
protected
void
onCreate(Bundle savedInstanceState) {
super
.onCreate(savedInstanceState);
setContentView(R.layout.
activity_main
);
iv
=(ImageView) findViewById(R.id.
iv
);
bt
=(Button) findViewById(R.id.
bt
);
iv_after
=(ImageView) findViewById(R.id.
iv_after
);
bt
.setOnClickListener(
this
);
}
/**
* 获取图片的方法
*
@param
v
*/
@Override
public
void
onClick(View v) {
//创建隐式意图
Intent intent=
new
Intent();
intent.setAction(
"android.intent.action.PICK"
);
intent.addCategory(intent.
CATEGORY_DEFAULT
);
intent.setType(
"image/*"
);
startActivityForResult(intent, 0);
}
/**
* 获取Activity返回的数据
*/
@Override
protected
void
onActivityResult(
int
requestCode,
int
resultCode, Intent data) {
super
.onActivityResult(requestCode, resultCode, data);
Uri uri = data.getData();
//接收到返回照片的 uri
iv
.setImageURI(uri);
try
{
//得到原图的bitmap 只读(要从这个bitmap读取像素点到其他的空白bitmap上)
Bitmap bitmap=BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
//创建一个空白可修改的bitmap b1
Bitmap alertBitmap=Bitmap.createBitmap(bitmap.getWidth()/2, bitmap.getHeight()/2, bitmap.getConfig());
//将空白可修改的bitmap作为画布 b2
Canvas canvas=
new
Canvas(alertBitmap);
//创建画笔
Paint paint=
new
Paint();
paint.setColor(Color.
GREEN
);
//在画布上画原图片的像素点
Matrix matrix =
new
Matrix();
matrix.setScale(0.5f,0.5f);
//设置x,y方向的缩放比
canvas.drawBitmap(bitmap, matrix, paint);
//1.原图 2.矩阵 3.画笔
//将画好的b2挂在iv上
iv_after
.setImageBitmap(alertBitmap);
}
catch
(Exception e) {
e.printStackTrace();
}
}
}