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。)

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)

以下是完整的代码:

package com.example.cameraa;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {




        Button btnTackPic;
        Uri photoPath;
        ImageView ivThumbnailPhoto;

        static int TAKE_PICTURE = 1;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            // Get reference to views

            btnTackPic = (Button) findViewById(R.id.bt1);
            ivThumbnailPhoto = (ImageView) findViewById(R.id.imageView1);




     btnTackPic.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub


                Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
                startActivityForResult(cameraIntent, TAKE_PICTURE); 
            }




    });

        } 

        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent intent) {


                if (requestCode == TAKE_PICTURE && resultCode == RESULT_OK) {  
                    Bitmap photo = (Bitmap)intent.getExtras().get("data"); 
                   ivThumbnailPhoto.setImageBitmap(photo);
                ivThumbnailPhoto.setVisibility(View.VISIBLE);



            }
        }
}

记住也要为相机添加权限。

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"/>

我知道这是一个相当老的线程，但所有这些解决方案都没有完成，当用户旋转相机时，不工作在一些设备上，因为onActivityResult中的数据是空的。这是我在很多设备上测试过的解决方案，到目前为止还没有遇到任何问题。

首先在activity中声明Uri变量:

private Uri uriFilePath;

然后创建临时文件夹，用于存储捕获的图像，并通过相机捕获图像:

PackageManager packageManager = getActivity().getPackageManager();
if (packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
    File mainDirectory = new File(Environment.getExternalStorageDirectory(), "MyFolder/tmp");
         if (!mainDirectory.exists())
             mainDirectory.mkdirs();

          Calendar calendar = Calendar.getInstance();

          uriFilePath = Uri.fromFile(new File(mainDirectory, "IMG_" + calendar.getTimeInMillis()));
          intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
          intent.putExtra(MediaStore.EXTRA_OUTPUT, uriFilePath);
          startActivityForResult(intent, 1);
}

这里有一个最重要的事情，你必须保存你的uriFilePath在onSaveInstanceState中，因为如果你不这样做，用户在使用camera时旋转他的设备，你的uri将为null。

@Override
protected void onSaveInstanceState(Bundle outState) {
     if (uriFilePath != null)
         outState.putString("uri_file_path", uriFilePath.toString());
     super.onSaveInstanceState(outState);
}

之后，你应该在onCreate方法中恢复你的uri:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
         if (uriFilePath == null && savedInstanceState.getString("uri_file_path") != null) {
             uriFilePath = Uri.parse(savedInstanceState.getString("uri_file_path"));
         }
    } 
}

这里是最后一部分，获得你的Uri在onActivityResult:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {    
    if (resultCode == RESULT_OK) {
         if (requestCode == 1) {
            String filePath = uriFilePath.getPath(); // Here is path of your captured image, so you can create bitmap from it, etc.
         }
    }
 }

附注:别忘了在你的Manifest中添加Camera和Ext. storage的写入权限。

下面是一个示例活动，它将启动相机应用程序，然后检索图像并显示它。

package edu.gvsu.cis.masl.camerademo;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MyCameraActivity extends Activity
{
    private static final int CAMERA_REQUEST = 1888; 
    private ImageView imageView;
    private static final int MY_CAMERA_PERMISSION_CODE = 100;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        this.imageView = (ImageView)this.findViewById(R.id.imageView1);
        Button photoButton = (Button) this.findViewById(R.id.button1);
        photoButton.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
                {
                    requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_PERMISSION_CODE);
                }
                else
                {
                    Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
                    startActivityForResult(cameraIntent, CAMERA_REQUEST);
                } 
            }
        });
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
    {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == MY_CAMERA_PERMISSION_CODE)
        {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
            {
                Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
                Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
                startActivityForResult(cameraIntent, CAMERA_REQUEST);
            }
            else
            {
                Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {  
        if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK)
        {  
            Bitmap photo = (Bitmap) data.getExtras().get("data"); 
            imageView.setImageBitmap(photo);
        }  
    } 
}

请注意，相机应用程序本身提供了查看/重拍图像的功能，一旦图像被接受，活动就会显示它。

下面是上面的活动使用的布局。它只是一个包含id为button1的Button和id为imageview1的ImageView的LinearLayout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/photo"></Button>
    <ImageView android:id="@+id/imageView1" android:layout_height="wrap_content" android:src="@drawable/icon" android:layout_width="wrap_content"></ImageView>

</LinearLayout>

最后一个细节，一定要加上:

<uses-feature android:name="android.hardware.camera"></uses-feature> 

如果摄像头是你应用功能的可选选项。请确保在权限中将require设置为false。像这样

<uses-feature android:name="android.hardware.camera" android:required="false"></uses-feature>

到你的manifest.xml。