Android 点击图片放大

这里是加载的网络图片（url），点击图片后，将url作为参数打开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();    }}