在Android中实现手势对于图片的操作,首先需要对MotionEvent以及Matrix两个类有所了解实现对手势的识别以及图片变动的操作。
在实现该功能时候需要在xml中要将图片的缩放格式改成Matrix才行.
下面代码主要实现两个demo,一个是关于matrix的简单测试以及图片的手势缩放与移动demo.。。
XML代码如下:
<?
xml
version
=
"1.0"
encoding
=
"UTF-8"
?>
<
LinearLayout
xmlns:android
=
"/apk/res/android"
android:orientation
=
"vertical"
android:layout_height
=
"fill_parent"
android:layout_width
=
"fill_parent"
android:id
=
"@+id/linearLayout1"
android:weightSum
=
"1"
>
<
ImageView
android:layout_width
=
"wrap_content"
android:id
=
"@+id/imag"
android:layout_height
=
"wrap_content"
android:src
=
"@drawable/a"
android:layout_gravity
=
"center"
android:scaleType
=
"matrix"
></
ImageView
>
<
ImageView
android:layout_width
=
"wrap_content"
android:id
=
"@+id/imag1"
android:scaleType
=
"matrix"
android:layout_height
=
"wrap_content"
></
ImageView
>
</
LinearLayout
>
实现代码:
package
hfut.gmm;
import
android.app.Activity;
import
android.content.Context;
import
android.graphics.Bitmap;
import
android.graphics.BitmapFactory;
import
android.graphics.Canvas;
import
android.graphics.Color;
import
android.graphics.Matrix;
import
android.graphics.Paint;
import
android.graphics.PointF;
import
android.os.Bundle;
import
android.util.DisplayMetrics;
import
android.util.FloatMath;
import
android.util.Log;
import
android.view.GestureDetector;
import
android.view.MotionEvent;
import
android.view.View;
import
android.view.GestureDetector.OnGestureListener;
import
android.view.View.OnTouchListener;
import
android.view.animation.AnimationUtils;
import
android.widget.ImageView;
public
class
Img_control
extends
Activity
implements
OnTouchListener {
//implements OnTouchListener {
private
ImageView imgview;
private
ImageView img;
private
Matrix matrix=
new
Matrix();
private
Matrix savedMatrix=
new
Matrix();
static
final
int
NONE =
0
;
static
final
int
DRAG =
1
;
static
final
int
ZOOM =
2
;
int
mode = NONE;
// Remember some things for zooming
PointF start =
new
PointF();
PointF mid =
new
PointF();
float
oldDist = 1f;
//private GestureDetector gesture;
@Override
protected
void
onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super
.onCreate(savedInstanceState);
this
.setContentView(R.layout.img_control);
imgview=(ImageView)
this
.findViewById(R.id.imag1);
imgview.setAnimation(AnimationUtils.loadAnimation(
this
, R.anim.newanim));
img=(ImageView)
this
.findViewById(R.id.imag);
Matrix mt=img.getImageMatrix();
//mt.postRotate(30);
mt.postScale(
0
.5f,
0
.5f);mt.postScale(
1
.5f,
1
.5f);
mt.postRotate(
30
,
130
,
100
);
mt.postTranslate(
100
,
10
);
img.setImageMatrix(mt);
//imgview.setLongClickable(true);
imgview.setImageBitmap(BitmapFactory.decodeResource(
this
.getResources(), R.drawable.a));
imgview.setOnTouchListener(
this
);
imgview.setLongClickable(
true
);
}
private
float
spacing(MotionEvent event) {
float
x = event.getX(
0
) - event.getX(
1
);
float
y = event.getY(
0
) - event.getY(
1
);
return
FloatMath.sqrt(x * x + y * y);
}
private
void
midPoint(PointF point, MotionEvent event) {
float
x = event.getX(
0
) + event.getX(
1
);
float
y = event.getY(
0
) + event.getY(
1
);
point.set(x /
2
, y /
2
);
}
@Override
public
boolean
onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
/*
Log.d("Infor", "类别:"+event.getAction());
Log.d("Infor", "mask:"+event.getActionMasked());
Log.d("Infor", "index:"+event.getActionIndex());
Log.d("Infor", "points:"+event.getPointerCount());*/
Log.d(
"Infor"
,
"size:"
+event.getSize());
if
(event.getActionMasked()==MotionEvent.ACTION_POINTER_UP)
Log.d(
"Infor"
,
"多点操作"
);
switch
(event.getActionMasked()){
case
MotionEvent.ACTION_DOWN:
matrix.set(imgview.getImageMatrix());
savedMatrix.set(matrix);
start.set(event.getX(),event.getY());
Log.d(
"Infor"
,
"触摸了..."
);
mode=DRAG;
break
;
case
MotionEvent.ACTION_POINTER_DOWN:
//多点触控
oldDist=
this
.spacing(event);
if
(oldDist>10f){
Log.d(
"Infor"
,
"oldDist"
+oldDist);
savedMatrix.set(matrix);
midPoint(mid,event);
mode=ZOOM;
}
break
;
case
MotionEvent.ACTION_POINTER_UP:
mode=NONE;
break
;
case
MotionEvent.ACTION_MOVE:
if
(mode==DRAG){
//此实现图片的拖动功能...
matrix.set(savedMatrix);
matrix.postTranslate(event.getX()-start.x, event.getY()-start.y);
}
else
if
(mode==ZOOM){
// 此实现图片的缩放功能...
float
newDist=spacing(event);
if
(newDist>
10
){
matrix.set(savedMatrix);
float
scale=newDist/oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break
;
}
imgview.setImageMatrix(matrix);
return
false
;
}
}
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