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
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!
你得好好研究一下相机。(我认为要做到你想要的，你必须保存当前的图像到你的应用程序，在那里做选择/删除，然后召回相机再试一次，而不是直接在相机内部重试。)
坏的质量
根据我的经验，如果我们使用
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, RESULT_ADD_PHOTO);
和处理onActivityResult()
Bitmap thumbnail= (Bitmap) data.getExtras().get("data");
它只会给你一个缩略图，当然有一个坏的质量。
不错的质量
您可以显示相机和保存您的图像文件在公共目录，例如在文档目录
在onClick()中使用这个
String imagePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) +
File.separator + "your_image_name.jpeg";
Intent i =new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
imageFile = new File(imagePath );
i.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(imageFile));
startActivityForResult(i, RESULT_ADD_PHOTO);
在onActivityResult()中
Bitmap imageBitmap1 = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
Matrix matrix = new Matrix();
matrix.postRotate(90);
Bitmap imageBitmap = Bitmap.createBitmap(imageBitmap1, 0, 0, imageBitmap1.getWidth(), imageBitmap1.getHeight(), matrix, true);
binding.imageView.setImageBitmap(imageBitmap);
我使用postRotate()，因为在我的代码中，图像结果向左旋转，所以我需要将其旋转90
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();
}
从相机捕获照片+从图库中选择图像，并将其设置为布局或imageview的背景。下面是示例代码。
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class Post_activity extends Activity
{
final int TAKE_PICTURE = 1;
final int ACTIVITY_SELECT_IMAGE = 2;
ImageView openCameraOrGalleryBtn,cancelBtn;
LinearLayout backGroundImageLinearLayout;
public void onCreate(Bundle savedBundleInstance) {
super.onCreate(savedBundleInstance);
overridePendingTransition(R.anim.slide_up,0);
setContentView(R.layout.post_activity);
backGroundImageLinearLayout=(LinearLayout)findViewById(R.id.background_image_linear_layout);
cancelBtn=(ImageView)findViewById(R.id.cancel_icon);
openCameraOrGalleryBtn=(ImageView)findViewById(R.id.camera_icon);
openCameraOrGalleryBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
selectImage();
}
});
cancelBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
overridePendingTransition(R.anim.slide_down,0);
finish();
}
});
}
public void selectImage()
{
final CharSequence[] options = { "Take Photo", "Choose from Gallery","Cancel" };
AlertDialog.Builder builder = new AlertDialog.Builder(Post_activity.this);
builder.setTitle("Add Photo!");
builder.setItems(options,new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
if(options[which].equals("Take Photo"))
{
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, TAKE_PICTURE);
}
else if(options[which].equals("Choose from Gallery"))
{
Intent intent=new Intent(Intent.ACTION_PICK,android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, ACTIVITY_SELECT_IMAGE);
}
else if(options[which].equals("Cancel"))
{
dialog.dismiss();
}
}
});
builder.show();
}
public void onActivityResult(int requestcode,int resultcode,Intent intent)
{
super.onActivityResult(requestcode, resultcode, intent);
if(resultcode==RESULT_OK)
{
if(requestcode==TAKE_PICTURE)
{
Bitmap photo = (Bitmap)intent.getExtras().get("data");
Drawable drawable=new BitmapDrawable(photo);
backGroundImageLinearLayout.setBackgroundDrawable(drawable);
}
else if(requestcode==ACTIVITY_SELECT_IMAGE)
{
Uri selectedImage = intent.getData();
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));
Drawable drawable=new BitmapDrawable(thumbnail);
backGroundImageLinearLayout.setBackgroundDrawable(drawable);
}
}
}
public void onBackPressed() {
super.onBackPressed();
//overridePendingTransition(R.anim.slide_down,0);
}
}
Add these permission in Androidmenifest.xml file
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.CAMERA"/>
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