我想写一个模块，在点击一个按钮，相机打开，我可以点击和捕捉图像。如果我不喜欢图像，我可以删除它，然后点击另一个图像，然后选择图像，它应该返回并在活动中显示该图像。
当前回答
正如其他人所讨论的，使用data. getextras ().get("data")只会得到低质量的缩略图。
解决方案是通过ACTION_IMAGE_CAPTURE意图传递一个位置，告诉相机在哪里存储全质量图像。
代码是Kotlin，不需要任何权限。
val f = File("${getExternalFilesDir(null)}/imgShot")
val photoURI = FileProvider.getUriForFile(this, "${packageName}.fileprovider", f)
val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
.apply { putExtra(MediaStore.EXTRA_OUTPUT, photoURI) }
startActivityForResult(intent, 1234)
然后对拍摄后的结果进行处理:
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
if (requestCode == 1234 && resultCode == Activity.RESULT_OK) {
val bitmap = BitmapFactory.decodeFile(
File("${getExternalFilesDir(null)}/imgShot").toString()
)
// use imageView.setImageBitmap(bitmap) or whatever
}
}
您还需要像这里描述的那样添加一个外部FileProvider。AndroidManifest.xml:
<manifest>
<application>
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provide_paths" />
</provider>
</application>
</manifest>
添加一个新文件app/src/main/res/xml/provide_paths.xml:
<?xml version="1.0" encoding="utf-8"?>
<paths>
<external-path name="external_files" path="." />
</paths>
最后，你应该用你自己的逻辑替换1234来跟踪请求代码(通常是一个包含RequestCode.CAPTURE_IMAGE等成员的枚举)
其他回答
位图照片=(位图)data. getextras ().get("data");从相机获取缩略图。有一篇文章是关于如何将照片从相机存储到外部存储器中。 有用的链接
更新(2020)
谷歌已经添加了一个新的ActivityResultRegistry API，“让你处理startActivityForResult() + onActivityResult()以及requestPermissions() + onRequestPermissionsResult()流，而无需覆盖你的活动或片段中的方法，通过ActivityResultContract带来了增加的类型安全性，并为测试这些流提供了钩子”。
该API是在androidx中添加的。和androidx.fragment 1.3.0-alpha02。
所以你现在可以这样做:
val takePicture = registerForActivityResult(ActivityResultContracts.TakePicture()) { success: Boolean ->
if (success) {
// The image was saved into the given Uri -> do something with it
}
}
val imageUri: Uri = ...
button.setOnClickListener {
takePicture.launch(imageUri)
}
查看文档了解如何使用新的Activity结果API: https://developer.android.com/training/basics/intents/result#kotlin
有许多内置的activityresultcontract，允许您做不同的事情，如选择联系人，请求权限，拍照或拍摄视频。您可能对ActivityResultContracts感兴趣。拍摄上图。
注意androidx.fragment 1.3.0-alpha04弃用了Fragment上的startActivityForResult() + onActivityResult()和requestPermissions() + onRequestPermissionsResult() api。因此，从现在开始ActivityResultContracts似乎是一种新的做事方式。
原答案(2015)
我花了好几个小时才把它修好。代码几乎是从developer.android.com复制粘贴而来的，只有细微的区别。
在AndroidManifest.xml上请求此权限:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
在你的Activity中，首先定义这个:
static final int REQUEST_IMAGE_CAPTURE = 1;
private Bitmap mImageBitmap;
private String mCurrentPhotoPath;
private ImageView mImageView;
然后在onClick中触发这个Intent:
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (cameraIntent.resolveActivity(getPackageManager()) != null) {
// Create the File where the photo should go
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
// Error occurred while creating the File
Log.i(TAG, "IOException");
}
// Continue only if the File was successfully created
if (photoFile != null) {
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
startActivityForResult(cameraIntent, REQUEST_IMAGE_CAPTURE);
}
}
添加以下支持方法:
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, // prefix
".jpg", // suffix
storageDir // directory
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = "file:" + image.getAbsolutePath();
return image;
}
然后接收结果:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
try {
mImageBitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), Uri.parse(mCurrentPhotoPath));
mImageView.setImageBitmap(mImageBitmap);
} catch (IOException e) {
e.printStackTrace();
}
}
}
使它工作的是MediaStore.Images.Media.getBitmap(this.getContentResolver()， Uri.parse(mCurrentPhotoPath))，这与developer.android.com的代码不同。原始代码给了我一个FileNotFoundException。
拍摄照片+从图库中选择:
a = (ImageButton)findViewById(R.id.imageButton1);
a.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
selectImage();
}
});
}
private File savebitmap(Bitmap bmp) {
String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
OutputStream outStream = null;
// String temp = null;
File file = new File(extStorageDirectory, "temp.png");
if (file.exists()) {
file.delete();
file = new File(extStorageDirectory, "temp.png");
}
try {
outStream = new FileOutputStream(file);
bmp.compress(Bitmap.CompressFormat.PNG, 100, outStream);
outStream.flush();
outStream.close();
} catch (Exception e) {
e.printStackTrace();
return null;
}
return file;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private void selectImage() {
final CharSequence[] options = { "Take Photo", "Choose from Gallery","Cancel" };
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setTitle("Add Photo!");
builder.setItems(options, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int item) {
if (options[item].equals("Take Photo"))
{
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
File f = new File(android.os.Environment.getExternalStorageDirectory(), "temp.jpg");
intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f));
//pic = f;
startActivityForResult(intent, 1);
}
else if (options[item].equals("Choose from Gallery"))
{
Intent intent = new Intent(Intent.ACTION_PICK,android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, 2);
}
else if (options[item].equals("Cancel")) {
dialog.dismiss();
}
}
});
builder.show();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK) {
if (requestCode == 1) {
//h=0;
File f = new File(Environment.getExternalStorageDirectory().toString());
for (File temp : f.listFiles()) {
if (temp.getName().equals("temp.jpg")) {
f = temp;
File photo = new File(Environment.getExternalStorageDirectory(), "temp.jpg");
//pic = photo;
break;
}
}
try {
Bitmap bitmap;
BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
bitmap = BitmapFactory.decodeFile(f.getAbsolutePath(),
bitmapOptions);
a.setImageBitmap(bitmap);
String path = android.os.Environment
.getExternalStorageDirectory()
+ File.separator
+ "Phoenix" + File.separator + "default";
//p = path;
f.delete();
OutputStream outFile = null;
File file = new File(path, String.valueOf(System.currentTimeMillis()) + ".jpg");
try {
outFile = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 85, outFile);
//pic=file;
outFile.flush();
outFile.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
} else if (requestCode == 2) {
Uri selectedImage = data.getData();
// h=1;
//imgui = selectedImage;
String[] filePath = { MediaStore.Images.Media.DATA };
Cursor c = getContentResolver().query(selectedImage,filePath, null, null, null);
c.moveToFirst();
int columnIndex = c.getColumnIndex(filePath[0]);
String picturePath = c.getString(columnIndex);
c.close();
Bitmap thumbnail = (BitmapFactory.decodeFile(picturePath));
Log.w("path of image from gallery......******************.........", picturePath+"");
a.setImageBitmap(thumbnail);
}
}
在这里你可以打开相机或图库，并设置选定的图像到imageview
private static final String IMAGE_DIRECTORY = "/YourDirectName";
private Context mContext;
private CircleImageView circleImageView; // imageview
private int GALLERY = 1, CAMERA = 2;
在清单中添加权限
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="ANDROID.PERMISSION.READ_EXTERNAL_STORAGE" />
在onCreate ()
requestMultiplePermissions(); // check permission
circleImageView = findViewById(R.id.profile_image);
circleImageView.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showPictureDialog();
}
});
显示选项对话框(用于从相机或图库中选择图像)
private void showPictureDialog() {
AlertDialog.Builder pictureDialog = new AlertDialog.Builder(this);
pictureDialog.setTitle("Select Action");
String[] pictureDialogItems = {"Select photo from gallery", "Capture photo from camera"};
pictureDialog.setItems(pictureDialogItems,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case 0:
choosePhotoFromGallary();
break;
case 1:
takePhotoFromCamera();
break;
}
}
});
pictureDialog.show();
}
从图库获取照片
public void choosePhotoFromGallary() {
Intent galleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(galleryIntent, GALLERY);
}
从相机中获取照片
private void takePhotoFromCamera() {
Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, CAMERA);
}
一旦图像被选中或捕获，
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == this.RESULT_CANCELED) {
return;
}
if (requestCode == GALLERY) {
if (data != null) {
Uri contentURI = data.getData();
try {
Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), contentURI);
String path = saveImage(bitmap);
Toast.makeText(getApplicationContext(), "Image Saved!", Toast.LENGTH_SHORT).show();
circleImageView.setImageBitmap(bitmap);
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Failed!", Toast.LENGTH_SHORT).show();
}
}
} else if (requestCode == CAMERA) {
Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
circleImageView.setImageBitmap(thumbnail);
saveImage(thumbnail);
Toast.makeText(getApplicationContext(), "Image Saved!", Toast.LENGTH_SHORT).show();
}
}
现在是存储图片的时候了
public String saveImage(Bitmap myBitmap) {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
myBitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
File wallpaperDirectory = new File(Environment.getExternalStorageDirectory() + IMAGE_DIRECTORY);
if (!wallpaperDirectory.exists()) { // have the object build the directory structure, if needed.
wallpaperDirectory.mkdirs();
}
try {
File f = new File(wallpaperDirectory, Calendar.getInstance().getTimeInMillis() + ".jpg");
f.createNewFile();
FileOutputStream fo = new FileOutputStream(f);
fo.write(bytes.toByteArray());
MediaScannerConnection.scanFile(this,
new String[]{f.getPath()},
new String[]{"image/jpeg"}, null);
fo.close();
Log.d("TAG", "File Saved::--->" + f.getAbsolutePath());
return f.getAbsolutePath();
} catch (IOException e1) {
e1.printStackTrace();
}
return "";
}
请求许可
private void requestMultiplePermissions() {
Dexter.withActivity(this)
.withPermissions(
Manifest.permission.CAMERA,
Manifest.permission.WRITE_EXTERNAL_STORAGE,
Manifest.permission.READ_EXTERNAL_STORAGE)
.withListener(new MultiplePermissionsListener() {
@Override
public void onPermissionsChecked(MultiplePermissionsReport report) {
if (report.areAllPermissionsGranted()) { // check if all permissions are granted
Toast.makeText(getApplicationContext(), "All permissions are granted by user!", Toast.LENGTH_SHORT).show();
}
if (report.isAnyPermissionPermanentlyDenied()) { // check for permanent denial of any permission
// show alert dialog navigating to Settings
//openSettingsDialog();
}
}
@Override
public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
token.continuePermissionRequest();
}
}).
withErrorListener(new PermissionRequestErrorListener() {
@Override
public void onError(DexterError error) {
Toast.makeText(getApplicationContext(), "Some Error! ", Toast.LENGTH_SHORT).show();
}
})
.onSameThread()
.check();
}
下面是我用来捕捉和保存相机图像然后显示到imageview的代码。您可以根据需要使用。
你必须保存相机图像到特定的位置，然后从该位置获取，然后将其转换为字节数组。
这里是打开捕捉相机图像活动的方法。
private static final int CAMERA_PHOTO = 111;
private Uri imageToUploadUri;
private void captureCameraImage() {
Intent chooserIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
File f = new File(Environment.getExternalStorageDirectory(), "POST_IMAGE.jpg");
chooserIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f));
imageToUploadUri = Uri.fromFile(f);
startActivityForResult(chooserIntent, CAMERA_PHOTO);
}
那么你的onActivityResult()方法应该是这样的。
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == CAMERA_PHOTO && resultCode == Activity.RESULT_OK) {
if(imageToUploadUri != null){
Uri selectedImage = imageToUploadUri;
getContentResolver().notifyChange(selectedImage, null);
Bitmap reducedSizeBitmap = getBitmap(imageToUploadUri.getPath());
if(reducedSizeBitmap != null){
ImgPhoto.setImageBitmap(reducedSizeBitmap);
Button uploadImageButton = (Button) findViewById(R.id.uploadUserImageButton);
uploadImageButton.setVisibility(View.VISIBLE);
}else{
Toast.makeText(this,"Error while capturing Image",Toast.LENGTH_LONG).show();
}
}else{
Toast.makeText(this,"Error while capturing Image",Toast.LENGTH_LONG).show();
}
}
}
下面是onActivityResult()中使用的getBitmap()方法。我已经做了所有的性能改进，可以同时获得相机捕捉图像位图。
private Bitmap getBitmap(String path) {
Uri uri = Uri.fromFile(new File(path));
InputStream in = null;
try {
final int IMAGE_MAX_SIZE = 1200000; // 1.2MP
in = getContentResolver().openInputStream(uri);
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(in, null, o);
in.close();
int scale = 1;
while ((o.outWidth * o.outHeight) * (1 / Math.pow(scale, 2)) >
IMAGE_MAX_SIZE) {
scale++;
}
Log.d("", "scale = " + scale + ", orig-width: " + o.outWidth + ", orig-height: " + o.outHeight);
Bitmap b = null;
in = getContentResolver().openInputStream(uri);
if (scale > 1) {
scale--;
// scale to max possible inSampleSize that still yields an image
// larger than target
o = new BitmapFactory.Options();
o.inSampleSize = scale;
b = BitmapFactory.decodeStream(in, null, o);
// resize to desired dimensions
int height = b.getHeight();
int width = b.getWidth();
Log.d("", "1th scale operation dimenions - width: " + width + ", height: " + height);
double y = Math.sqrt(IMAGE_MAX_SIZE
/ (((double) width) / height));
double x = (y / height) * width;
Bitmap scaledBitmap = Bitmap.createScaledBitmap(b, (int) x,
(int) y, true);
b.recycle();
b = scaledBitmap;
System.gc();
} else {
b = BitmapFactory.decodeStream(in);
}
in.close();
Log.d("", "bitmap size - width: " + b.getWidth() + ", height: " +
b.getHeight());
return b;
} catch (IOException e) {
Log.e("", e.getMessage(), e);
return null;
}
}
希望能有所帮助!
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