Android 捕获和显示图像应用程序
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【中文标题】Android 捕获和显示图像应用程序【英文标题】：Android capture and display image app 【发布时间】：2014-01-20 09:06:38 【问题描述】：我是 android 应用开发的新手，正在尝试制作一个简单的应用程序，
-
使用系统相机应用程序通过传递相机意图来拍照。
将图像存储在文件系统的公用文件夹中。
然后从其绝对路径中获取图像，将其转换为位图，并通过对其执行一些缩小操作将其显示在图像视图中。
这是我的代码....
static final int REQUEST_IMAGE_CAPTURE = 1;
String mCurrentPhotoPath;
Button captureImageButton;
static ImageView imageCapturedView;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_take_image);
captureImageButton = (Button) findViewById(R.id.button);
OnClickListener captureImageListener = new OnClickListener()
@Override
public void onClick(View v)
// TODO Auto-generated method stub
Intent captureImageIntent= new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if(captureImageIntent.resolveActivity(getPackageManager())!=null)
File photoFile=null;
try
photoFile = createImageFile();
catch(IOException e);
if(photoFile != null)
captureImageIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
startActivityForResult(captureImageIntent, REQUEST_IMAGE_CAPTURE);
;
captureImageButton.setOnClickListener(captureImageListener);
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
imageCapturedView = (ImageView)findViewById(R.id.ImageView);
if(requestCode==REQUEST_IMAGE_CAPTURE && resultCode==RESULT_OK)
Bundle extras = data.getExtras();
Bitmap imageBitmap= (Bitmap) extras.get("data");
imageCapturedView.setImageBitmap(imageBitmap);
galleryAddPic();
setPic();
private File createImageFile() throws IOException
String TimeStamp = new SimpleDateFormat("yyyyMMDdd_HHmmss").format(new Date());
String ImageFile = "JPEG_" + TimeStamp + "_";
File StorageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(ImageFile, ".jpg", StorageDir);
mCurrentPhotoPath = image.getAbsolutePath();
return image;
private void galleryAddPic()
Intent mediaScan = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
File f= new File(mCurrentPhotoPath);
Uri contentUri = Uri.fromFile(f);
mediaScan.setData(contentUri);
this.sendBroadcast(mediaScan);
private void setPic() throws ArithmeticException
int scaleFactor;
Bitmap bitmap;
// Get the dimensions of the View
int targetW = imageCapturedView.getWidth();
int targetH = imageCapturedView.getHeight();
// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
//bmOptions.inSampleSize = 4;
BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
scaleFactor= Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
Toast.makeText(getApplicationContext(), mCurrentPhotoPath, Toast.LENGTH_LONG).show();
imageCapturedView.setImageBitmap(bitmap);
@Override
public boolean onCreateOptionsMenu(Menu menu)
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.take_image, menu);
return true;
根据我的说法，这里的问题在于 setPic 函数，但我不知道它是什么，因为我刚刚按照 developer.android 上给出的教程进行操作
我能够捕获图像并将其存储在 sd 卡中，但无法在图像视图中显示它。根据图像视图属性缩放位图时出现问题。
这是我遇到的错误
01-20 14:32:34.736: E/AndroidRuntime(2513): FATAL EXCEPTION: main
01-20 14:32:34.736: E/AndroidRuntime(2513): java.lang.RuntimeException: Failure delivering result ResultInfowho=null, request=1, result=-1, data=Intent act=inline-data dat=file:///storage/sdcard0/Pictures/JPEG_2014012020_143223_-1472164486.jpg typ=image/jpeg (has extras) to activity yogesh.atArxxus.ocr_trial_application/yogesh.atArxxus.ocr_trial_application.Take_image: java.lang.ArithmeticException: divide by zero
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.ActivityThread.deliverResults(ActivityThread.java:3161)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3204)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.ActivityThread.access$1100(ActivityThread.java:137)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1254)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.os.Handler.dispatchMessage(Handler.java:99)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.os.Looper.loop(Looper.java:213)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.ActivityThread.main(ActivityThread.java:4793)
01-20 14:32:34.736: E/AndroidRuntime(2513): at java.lang.reflect.Method.invokeNative(Native Method)
01-20 14:32:34.736: E/AndroidRuntime(2513): at java.lang.reflect.Method.invoke(Method.java:511)
01-20 14:32:34.736: E/AndroidRuntime(2513): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
01-20 14:32:34.736: E/AndroidRuntime(2513): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
01-20 14:32:34.736: E/AndroidRuntime(2513): at dalvik.system.NativeStart.main(Native Method)
01-20 14:32:34.736: E/AndroidRuntime(2513): Caused by: java.lang.ArithmeticException: divide by zero
01-20 14:32:34.736: E/AndroidRuntime(2513): at yogesh.atArxxus.ocr_trial_application.Take_image.setPic(Take_image.java:136)
01-20 14:32:34.736: E/AndroidRuntime(2513): at yogesh.atArxxus.ocr_trial_application.Take_image.onActivityResult(Take_image.java:87)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.Activity.dispatchActivityResult(Activity.java:5192)
01-20 14:32:34.736: E/AndroidRuntime(2513): at android.app.ActivityThread.deliverResults(ActivityThread.java:3157)
谢谢
【问题讨论】：
如果我删除缩放代码并简单地尝试在图像视图中显示图像，那么它就可以工作了。不知道有什么问题，我如何让 targetW targetH 这个值在某处为零。 我也有类似的问题。所以请检查下面的链接，它可能对你有用。 ***.com/questions/21136311/… @Biplab 那么你是否使用了那个图像选择器库...？ 是的，我已经使用了它并且它的工作干净 @Biplab 感谢库工作正常，但实际上我上面的代码也完成了这件事......唯一的问题是通过缩小位图在图像视图中显示完整图像......在您提到的库中，它还提供缩略图而不是图像的预览。是这样吗..？ 【参考方案1】：在“scaleFactor= Math.min(photoW/targetW, photoH/targetH);”行中，targetW 或 targetH 或两者都为零。只需在该行之前添加一个像这样的简单验证即可。
if(targetH == 0) targetH = 1;
if(targetW == 0) targetW = 1;
您的下一步应该是调试其中一个包含零的原因。
【讨论】：
是的，这实际上是我的问题...我调试了程序并知道其中一个值变为零，因此用于缩放的公式的分母为 0 并且应用程序失败....但不是确定为什么这些值变成 0 ..？实际上没有理由..？我只是得到我的 imageView 的高度和宽度.. 在 xml 中，ImageView (R.id.ImageView) 的 layout-width 和 layout-height 尺寸是否固定？ 知道了。请参考这些答案 - ***.com/questions/4680499/… 和 ***.com/questions/10411975/… 。实际上，更好的方法是将尺寸存储在尺寸值 xml 中，并使用该尺寸在 xml 布局文件中设置图像视图的尺寸，并使用相同的尺寸（来自值 xml）在 setPic() 方法中缩放图像 @Srikanh ys 明白了....错误是在 XML 中，我将图像视图的宽度和高度保持为 fillparent 和 wrapcontent 所以我得到的两个值都是 0...如果我保持固定dp 的高度和宽度值然后它可以工作.....甚至可以尝试使用 getMeasuredHeight 和 getMeasuredWIdth .....谢谢【参考方案2】：试试这个，但它没有正确测试
public class MainActivity extends Activity
// Activity request codes
private static final int CAMERA_CAPTURE_IMAGE_REQUEST_CODE = 100;
private static final int CAMERA_CAPTURE_VIDEO_REQUEST_CODE = 200;
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
public static int RESULT_LOAD_IMAGE = 1;
// directory name to store captured images and videos
private static final String IMAGE_DIRECTORY_NAME = "Hello Camera";
private Uri fileUri; // file url to store image/video
private ImageView imgPreview;
private VideoView videoPreview;
private Button btnCapturePicture, btnRecordVideo;
private ImageButton captureImage,browsImage;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imgPreview = (ImageView) findViewById(R.id.imgPreview);
videoPreview = (VideoView) findViewById(R.id.videoPreview);
btnCapturePicture = (Button) findViewById(R.id.btnCapturePicture);
btnRecordVideo = (Button) findViewById(R.id.btnRecordVideo);
captureImage = (ImageButton) findViewById(R.id.captureImage);
browsImage = (ImageButton) findViewById(R.id.browsImage);
/*
* Capture image button click event
*/
captureImage.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
// capture picture
captureImage();
);
browsImage.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
// capture pictur
Intent i = new Intent(Intent.ACTION_PICK,
android.provider.MediaStore
.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(i, RESULT_LOAD_IMAGE);
);
/*
* Record video button click event
*/
btnRecordVideo.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
// record video
recordVideo();
);
// Checking camera availability
if (!isDeviceSupportCamera())
Toast.makeText(getApplicationContext(),
"Sorry! Your device doesn't support camera",
Toast.LENGTH_LONG).show();
// will close the app if the device does't have camera
finish();
/**
* Checking device has camera hardware or not
* */
private boolean isDeviceSupportCamera()
if (getApplicationContext().getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA))
// this device has a camera
return true;
else
// no camera on this device
return false;
/*
* Capturing Camera Image will lauch camera app requrest image capture
*/
private void captureImage()
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
// start the image capture Intent
startActivityForResult(intent, CAMERA_CAPTURE_IMAGE_REQUEST_CODE);
/*
* Here we store the file url as it will be null after returning from camera
* app
*/
@Override
protected void onSaveInstanceState(Bundle outState)
super.onSaveInstanceState(outState);
// save file url in bundle as it will be null on scren orientation
// changes
outState.putParcelable("file_uri", fileUri);
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
super.onRestoreInstanceState(savedInstanceState);
// get the file url
fileUri = savedInstanceState.getParcelable("file_uri");
/*
* Recording video
*/
private void recordVideo()
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);
// set video quality
intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file
// name
// start the video capture Intent
startActivityForResult(intent, CAMERA_CAPTURE_VIDEO_REQUEST_CODE);
/**
* Receiving activity result method will be called after closing the camera
* */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
// if the result is capturing Image
if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE)
if (resultCode == RESULT_OK)
// successfully captured the image
// display it in image view
previewCapturedImage();
else if (resultCode == RESULT_CANCELED)
// user cancelled Image capture
Toast.makeText(getApplicationContext(),
"User cancelled image capture", Toast.LENGTH_SHORT)
.show();
else
// failed to capture image
Toast.makeText(getApplicationContext(),
"Sorry! Failed to capture image", Toast.LENGTH_SHORT)
.show();
else if (requestCode == CAMERA_CAPTURE_VIDEO_REQUEST_CODE)
if (resultCode == RESULT_OK)
// video successfully recorded
// preview the recorded video
previewVideo();
else if (resultCode == RESULT_CANCELED)
// user cancelled recording
Toast.makeText(getApplicationContext(),
"User cancelled video recording", Toast.LENGTH_SHORT)
.show();
else
// failed to record video
Toast.makeText(getApplicationContext(),
"Sorry! Failed to record video", Toast.LENGTH_SHORT)
.show();
else if (requestCode == RESULT_LOAD_IMAGE)
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && null != data)
Uri selectedImage = data.getData();
String[] filePathColumn = MediaStore.Images.Media.DATA ;
Cursor cursor = getContentResolver().query(selectedImage,
filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
Bitmap bm=BitmapFactory
.decodeFile(picturePath);
Bitmap pic=ShrinkBitmap(picturePath,100,100);
imgPreview = (ImageView) findViewById(R.id.imgPreview);
imgPreview.setVisibility(View.VISIBLE);
imgPreview.setImageBitmap(pic);
/*
* Display image from a path to ImageView
*/
private void previewCapturedImage()
try
// hide video preview
videoPreview.setVisibility(View.GONE);
imgPreview.setVisibility(View.VISIBLE);
// bimatp factory
BitmapFactory.Options options = new BitmapFactory.Options();
// downsizing image as it throws OutOfMemory Exception for larger
// images
options.inSampleSize = 6;
final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(),
options);
try
File file = new File (fileUri.getPath());
FileOutputStream out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 95, out);
imgPreview.setImageBitmap(bitmap);
out.flush();
out.close();
catch (Exception e)
e.printStackTrace();
catch (NullPointerException e)
e.printStackTrace();
/*
* Previewing recorded video
*/
private void previewVideo()
try
// hide image preview
imgPreview.setVisibility(View.GONE);
videoPreview.setVisibility(View.VISIBLE);
videoPreview.setVideoPath(fileUri.getPath());
// start playing
videoPreview.start();
catch (Exception e)
e.printStackTrace();
/**
* ------------ Helper Methods ----------------------
* */
/*
* Creating file uri to store image/video
*/
public Uri getOutputMediaFileUri(int type)
return Uri.fromFile(getOutputMediaFile(type));
/*
* returning image / video
*/
private static File getOutputMediaFile(int type)
// External sdcard location
File mediaStorageDir = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
IMAGE_DIRECTORY_NAME);
// Create the storage directory if it does not exist
if (!mediaStorageDir.exists())
if (!mediaStorageDir.mkdirs())
Log.d(IMAGE_DIRECTORY_NAME, "Oops! Failed create "
+ IMAGE_DIRECTORY_NAME + " directory");
return null;
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
Locale.getDefault()).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE)
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg");
else if (type == MEDIA_TYPE_VIDEO)
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "VID_" + timeStamp + ".mp4");
else
return null;
return mediaFile;
Bitmap ShrinkBitmap(String file, int width, int height)
BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
bmpFactoryOptions.inJustDecodeBounds = true;
Bitmap bitmap = BitmapFactory.decodeFile(file, bmpFactoryOptions);
int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)height);
int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)width);
if (heightRatio > 1 || widthRatio > 1)
if (heightRatio > widthRatio)
bmpFactoryOptions.inSampleSize = heightRatio;
else
bmpFactoryOptions.inSampleSize = widthRatio;
bmpFactoryOptions.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeFile(file, bmpFactoryOptions);
return bitmap;
**XML 文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
android:orientation="horizontal"
android:baselineAligned="false"
tools:context=".MainActivity" >
<LinearLayout
android:layout_
android:layout_
android:layout_weight="1"
android:gravity="center"
android:orientation="vertical" >
<!-- Capture picture button -->
<ImageButton
android:id="@+id/captureImage"
android:layout_
android:layout_
android:src="@drawable/camera" />
<ImageButton
android:id="@+id/browsImage"
android:layout_
android:layout_
android:src="@drawable/brows" />
<Button
android:id="@+id/btnCapturePicture"
android:layout_
android:layout_
android:text="Take a Picture"
android:visibility="gone"
android:layout_marginBottom="10dp"/>
<!-- Record video button -->
<Button
android:id="@+id/btnRecordVideo"
android:layout_
android:layout_
android:visibility="gone"
android:text="Record a Video" />
</LinearLayout>
<LinearLayout
android:layout_
android:layout_
android:layout_weight="1"
android:orientation="vertical"
android:padding="10dp">
<TextView
android:layout_
android:layout_
android:text="Preview"
android:padding="10dp"
android:textSize="15dp"/>
<!-- To display picture taken -->
<ImageView
android:id="@+id/imgPreview"
android:layout_
android:layout_
android:visibility="gone" />
<!-- To preview video recorded -->
<VideoView
android:id="@+id/videoPreview"
android:layout_
android:layout_
android:visibility="gone" />
</LinearLayout>
【讨论】：
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