Android 点击图片放大

Activity

使用方法

Intent intent = new Intent();
intent.setClass(QuestionSingleChoiceActivity.this, PicturePreviewActivity.class);
intent.putExtra("url", url);
startActivity(intent);

Activity代码（复制使用即可）

/**
* 大图预览 功能描述：一般我们浏览一个应用，别人发布的状态或新闻都会有很多配图， 我们点击图片时可以浏览大图，这张大图一般可以放大，放大到超过屏幕后
* 可以移动 需要从activity的Intent传参数过来 传入参数：url 大图下载地址 smallPath 缩略图存在本地的地址
*
* @author Administrator
*/
public class PicturePreviewActivity extends Activity {
private ZoomImageView zoomView;
private Context ctx;
private GestureDetector gestureDetector;
private LinearLayout layout;
private boolean isFile;
private String TAG = PicturePreviewActivity.class.getSimpleName();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
//不显示系统的标题栏
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_picture_preview);
ctx = this;
zoomView = (ZoomImageView) findViewById(R.id.zoom_view);
zoomView.getActivity(PicturePreviewActivity.this);
layout = (LinearLayout) this.findViewById(R.id.layout_picture_preview);
/* 大图的下载地址 */
final String url = getIntent().getStringExtra("url");

if (url.startsWith("http:")) {//是网络地址
this.isFile = false;
} else {
this.isFile = true;
}

/* 缩略图存储在本地的地址 */
final String smallPath = getIntent().getStringExtra("smallPath");
final int identify = getIntent().getIntExtra("indentify", -1);
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
final int widthPixels = metrics.widthPixels;
final int heightPixels = metrics.heightPixels;
File bigPicFile = new File(getLocalPath(url));

layout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Log.i(TAG, "背景被点击");
PicturePreviewActivity.this.finish();
}
});

if (isFile) {
zoomView.setImageBitmap(zoomBitmap(
BitmapFactory.decodeFile(url), widthPixels,
heightPixels));
} else {

if (bigPicFile.exists()) {/* 如果已经下载过了,直接从本地文件中读取 */
zoomView.setImageBitmap(zoomBitmap(
BitmapFactory.decodeFile(getLocalPath(url)), widthPixels,
heightPixels));
} else if (!TextUtils.isEmpty(url)) {
ProgressDialogHandle handle = new ProgressDialogHandle(this) {
Bitmap bitmap = null;

@Override
public void handleData() throws
Exception {

if (!isFile)  //从网络读取
bitmap = getBitMapFromUrl(url);

if (bitmap != null) {
savePhotoToSDCard(
zoomBitmap(bitmap, widthPixels, heightPixels),
getLocalPath(url));
}
}

@Override
public String initialContent() {
return null;
}

@Override
public void updateUI() {
if (bitmap != null) {
// recycle();

zoomView.setImageBitmap(zoomBitmap(bitmap, widthPixels,
heightPixels));
} else {
Toast.makeText(ctx, "图片预览图下载失败",
Toast.LENGTH_LONG).show();
PicturePreviewActivity.this.finish();
}
}

};
if (TextUtils.isEmpty(smallPath) && identify != -1) {
handle.setBackground(BitmapFactory.decodeResource(
getResources(), identify));
} else {
handle.setBackground(BitmapFactory.decodeFile(smallPath));
}
handle.show();
}
}
gestureDetector = new GestureDetector(this,
new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2,
float velocityX, float velocityY) {
float x = e2.getX() - e1.getX();
if (x > 0) {
prePicture();
} else if (x < 0) {

nextPicture();
}
return true;
}
});
}

protected void nextPicture() {
// TODO Auto-generated method stub

}

protected void prePicture() {
// TODO Auto-generated method stub

}

@Override
public void onResume() {
super.onResume();
// recycle();
}

public void recycle() {
if (zoomView != null && zoomView.getDrawable() != null) {
BitmapDrawable bitmapDrawable = (BitmapDrawable) zoomView
.getDrawable();
if (bitmapDrawable != null && bitmapDrawable.getBitmap() != null
&& !bitmapDrawable.getBitmap().isRecycled())

{
bitmapDrawable.getBitmap().recycle();
}
}
}

public Bitmap getBitMapFromUrl(String url) {
Bitmap bitmap = null;
URL u = null;
HttpURLConnection conn = null;
InputStream is = null;
try {
u = new URL(url);
conn = (HttpURLConnection) u.openConnection();
is = conn.getInputStream();
bitmap = BitmapFactory.decodeStream(is);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (is != null) {
is.close();
}

} catch (IOException e) {
e.printStackTrace();
}
conn.disconnect();
}
return bitmap;
}

@Override
public boolean onTouchEvent(MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}

/**
* Resize the bitmap
*
* @param bitmap
* @param width
* @param height
* @return
*/
public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) {
if (bitmap == null)
return bitmap;
int w = bitmap.getWidth();
int h = bitmap.getHeight();
Matrix matrix = new Matrix();
float scaleWidth = ((float) width / w);
float scaleHeight = ((float) height / h);
if (scaleWidth < scaleHeight) {
matrix.postScale(scaleWidth, scaleWidth);
} else {
matrix.postScale(scaleHeight, scaleHeight);
}
Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
return newbmp;
}

public static String getLocalPath(String url) {
String fileName = "temp.png";
if (url != null) {
if (url.contains("/")) {
fileName = url
.substring(url.lastIndexOf("/") + 1, url.length());
}
if (fileName != null && fileName.contains("&")) {
fileName = fileName.replaceAll("&", "");
}
if (fileName != null && fileName.contains("%")) {
fileName = fileName.replaceAll("%", "");
}
}
return Environment.getExternalStorageDirectory() + "/weike/PracticeImage/" + fileName;
}

public static void savePhotoToSDCard(Bitmap photoBitmap, String fullPath) {
if (checkSDCardAvailable()) {
File file = new File(fullPath);
if (!file.getParentFile().exists()) {
file.getParentFile().mkdirs();
}

File photoFile = new File(fullPath);
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(photoFile);
if (photoBitmap != null) {
if (photoBitmap.compress(Bitmap.CompressFormat.PNG, 100,
fileOutputStream)) {
fileOutputStream.flush();
}
}
} catch (FileNotFoundException e) {
photoFile.delete();
e.printStackTrace();
} catch (IOException e) {
photoFile.delete();
e.printStackTrace();
} finally {
try {
if (fileOutputStream != null) {
fileOutputStream.close();
}
// if (photoBitmap != null && !photoBitmap.isRecycled()) {
// photoBitmap.recycle();
// }
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

public static boolean checkSDCardAvailable() {
return android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED);
}

public void closeActivity() {
this.finish();
}

}