这篇图片拖拽缩放也是我在项目中用到的，今天整理一下，将源码奉献给大家，希望对大家以后碰到相似的问题有帮助。
这篇就不做过多介绍了，直接上源码：
001 |
public class SpacePageActivity extends Activity { |
002 |
|
003 |
private LinearLayout linnerLayout_spacepage; |
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private RelativeLayout relativeLayout_spacepage; |
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private Button btn_spacepage_back; |
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private Button btn_spacepage_save; |
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private static Boolean isTrue=false; |
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|
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private static String IMAGE_MIME_TYPE ; |
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|
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private ImageView image_spacePage; |
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private ProgressDialog dialog; |
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private Bitmap bitmap; |
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@Override |
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protected void onCreate(Bundle savedInstanceState) { |
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// TODO Auto-generated method stub |
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super.onCreate(savedInstanceState); |
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requestWindowFeature(Window.FEATURE_NO_TITLE);//隐藏标题 |
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setContentView(R.layout.spacepage); |
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setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); |
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initHead(); |
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|
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if(isNetworkAvailable()){ |
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image_spacePage=(ImageView) findViewById(R.id.image_spacepage); |
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btn_spacepage_save=(Button) findViewById(R.id.btn_spacepage_save); |
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image_spacePage.setOnTouchListener(new MulitPointTouchListener(image_spacePage)); |
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image_spacePage.setScaleType(ScaleType.CENTER_INSIDE); |
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|
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//加载成功 |
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String urls="http://epaper.yzdsb.com.cn/201201/04/yz2104_7.jpg"; |
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bitmap=returnBitMap(urls); |
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if(null!=bitmap){ |
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image_spacePage.setImageBitmap(bitmap); |
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} |
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|
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} |
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} |
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|
039 |
|
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public Bitmap returnBitMap(String url) { |
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|
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if(null==url || "".equals(url)){ |
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return null; |
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} |
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URL myFileUrl = null; |
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Bitmap bitmap = null; |
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try { |
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myFileUrl = new URL(url); |
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} catch (MalformedURLException e) { |
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e.printStackTrace(); |
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} |
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try { |
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HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection(); |
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conn.setConnectTimeout(2000); |
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conn.setDoInput(true); |
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conn.connect(); |
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InputStream is = conn.getInputStream(); |
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bitmap = BitmapFactory.decodeStream(is); |
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is.close(); |
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} catch (IOException e) { |
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e.printStackTrace(); |
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} |
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|
064 |
|
065 |
|
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return bitmap; |
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} |
068 |
public class MulitPointTouchListener implements OnTouchListener { |
069 |
|
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Matrix matrix = new Matrix(); |
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Matrix savedMatrix = new Matrix(); |
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|
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public ImageView image; |
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static final int NONE = 0; |
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static final int DRAG = 1; |
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static final int ZOOM = 2; |
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int mode = NONE; |
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|
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PointF start = new PointF(); |
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PointF mid = new PointF(); |
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float oldDist = 1f; |
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|
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|
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public MulitPointTouchListener(ImageView image) { |
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super(); |
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this.image = image; |
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} |
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|
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@Override |
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public boolean onTouch(View v, MotionEvent event) { |
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this.image.setScaleType(ScaleType.MATRIX); |
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|
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ImageView view = (ImageView) v; |
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// dumpEvent(event); |
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|
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switch (event.getAction() & MotionEvent.ACTION_MASK) { |
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|
098 |
case MotionEvent.ACTION_DOWN: |
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|
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Log.w("FLAG", "ACTION_DOWN"); |
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matrix.set(view.getImageMatrix()); |
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savedMatrix.set(matrix); |
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start.set(event.getX(), event.getY()); |
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mode = DRAG; |
105 |
break; |
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case MotionEvent.ACTION_POINTER_DOWN: |
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Log.w("FLAG", "ACTION_POINTER_DOWN"); |
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oldDist = spacing(event); |
109 |
if (oldDist > 10f) { |
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savedMatrix.set(matrix); |
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midPoint(mid, event); |
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mode = ZOOM; |
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} |
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break; |
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case MotionEvent.ACTION_UP: |
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Log.w("FLAG", "ACTION_UP"); |
117 |
case MotionEvent.ACTION_POINTER_UP: |
118 |
Log.w("FLAG", "ACTION_POINTER_UP"); |
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mode = NONE; |
120 |
break; |
121 |
case MotionEvent.ACTION_MOVE: |
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Log.w("FLAG", "ACTION_MOVE"); |
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if (mode == DRAG) { |
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matrix.set(savedMatrix); |
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matrix.postTranslate(event.getX() - start.x, event.getY() |
126 |
- start.y); |
127 |
} else if (mode == ZOOM) { |
128 |
float newDist = spacing(event); |
129 |
if (newDist > 10f) { |
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matrix.set(savedMatrix); |
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float scale = newDist / oldDist; |
132 |
matrix.postScale(scale, scale, mid.x, mid.y); |
133 |
} |
134 |
} |
135 |
break; |
136 |
} |
137 |
|
138 |
view.setImageMatrix(matrix); |
139 |
return true; |
140 |
} |
141 |
|
142 |
|
143 |
private float spacing(MotionEvent event) { |
144 |
float x = event.getX(0) - event.getX(1); |
145 |
float y = event.getY(0) - event.getY(1); |
146 |
return FloatMath.sqrt(x * x + y * y); |
147 |
} |
148 |
|
149 |
private void midPoint(PointF point, MotionEvent event) { |
150 |
float x = event.getX(0) + event.getX(1); |
151 |
float y = event.getY(0) + event.getY(1); |
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point.set(x / 2, y / 2); |
153 |
} |
154 |
} |
155 |
private void initHead() { |
156 |
linnerLayout_spacepage = (LinearLayout) findViewById(R.id.linnerLayout_spacepage); |
157 |
relativeLayout_spacepage=(RelativeLayout) findViewById(R.id.relativeLayout_spacepage); |
158 |
btn_spacepage_back = (Button) findViewById(R.id.btn_spacepage_back); |
159 |
btn_spacepage_back.setOnClickListener(new OnClickListener() { |
160 |
|
161 |
@Override |
162 |
public void onClick(View v) { |
163 |
// TODO Auto-generated method stub |
164 |
|
165 |
finish(); |
166 |
} |
167 |
}); |
168 |
btn_spacepage_save = (Button) findViewById(R.id.btn_spacepage_save); |
169 |
|
170 |
} |
171 |
protected boolean isNetworkAvailable() { |
172 |
ConnectivityManager connectivity = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); |
173 |
if (connectivity == null) { |
174 |
Log.i("NetWorkState", "Unavailabel"); |
175 |
return false; |
176 |
} else { |
177 |
NetworkInfo[] info = connectivity.getAllNetworkInfo(); |
178 |
if (info != null) { |
179 |
for (int i = 0; i < info.length; i++) { |
180 |
if (info[i].getState() == NetworkInfo.State.CONNECTED) { |
181 |
Log.i("NetWorkState", "Availabel"); |
182 |
return true; |
183 |
} |
184 |
} |
185 |
} |
186 |
} |
187 |
return false; |
188 |
} |
189 |
@Override |
190 |
protected void onStop() { |
191 |
// TODO Auto-generated method stub |
192 |
if(bitmap!=null){ |
193 |
if(!bitmap.isRecycled()){ |
194 |
bitmap.recycle(); //回收图片所占的内存 |
195 |
bitmap=null; |
196 |
System.gc(); //提醒系统及时回收 |
197 |
} |
198 |
} |
199 |
super.onStop(); |
200 |
} |
201 |
@Override |
202 |
protected void onDestroy() { |
203 |
// TODO Auto-generated method stub |
204 |
super.onDestroy(); |
205 |
if(bitmap!=null){ |
206 |
if(!bitmap.isRecycled()){ |
207 |
bitmap.recycle(); //回收图片所占的内存 |
208 |
bitmap=null; |
209 |
System.gc(); //提醒系统及时回收 |
210 |
} |
211 |
} |
212 |
} |
213 |
} |
因为是大图片，在onDestroy的时候要recycle掉，这样系统才会定时回收掉，System.gc();是提醒系统回收，虽然java这种垃圾 回收机制不用我们自己关心对象的回收，但是这也给android开发人员带来了不好的一面，如果系统回收不及时很可能就造成了内存溢出了。什么时候手机不 担心内存使用了就好了。
运行一下看看效果：
转自：http://blog.csdn.net/wangkuifeng0118/article/details/7648692