如何在Android的相机和图库中裁剪图像？

在上一篇文章中，我们讨论了如何从Android的Gallery中选择图像，但是在此项目中，没有裁切功能。有时我们会在手机上拍照，并希望将其更新为个人资料照片。但是我们需要删除背景。因此，在这种情况下，我们可以使用裁剪图像功能删除该背景，然后再上传该图像。下面提供了一个示例视频，以使您对我们在本文中将要做的事情有个大概的了解。注意，我们将使用Java语言实现该项目。

分步实施

步骤1：创建一个新项目

要在Android Studio中创建新项目，请参阅如何在Android Studio中创建/启动新项目。请注意，选择Java作为编程语言。

步骤2：将依赖项添加到build.gradle(Module：app)文件中

导航到Gradle脚本> build.gradle(Module：app)并将以下依赖项添加到“依赖项”部分。

// This library is used for crop image feature

api ‘com.theartofdev.edmodo:android-image-cropper:2.8.+’

// This library is used for loading the  

// cropped image into ImageView.

implementation ‘com.squareup.picasso:picasso:2.5.2’

步骤3：使用AndroidManifest.xml文件

将以下权限添加到AndroidManifest.xml文件。

在标记内添加以下行。

 android:name=”com.theartofdev.edmodo.cropper.CropImageActivity”

 android:theme=”@style/Base.Theme.AppCompat” />

以下是完整的AndroidManifest.xml文件的代码。

步骤3：使用activity_main.xml文件

导航到应用程序> res>布局> activity_main.xml，然后将以下代码添加到该文件中。以下是activity_main.xml文件的代码。

步骤4：使用MainActivity。 Java文件

转到MainActivity。 Java文件并参考以下代码。下面是MainActivity的代码。 Java文件。在代码内部添加了注释，以更详细地了解代码。

Java

import android.Manifest;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
  
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
  
import com.squareup.picasso.Picasso;
import com.theartofdev.edmodo.cropper.CropImage;
  
public class MainActivity extends AppCompatActivity {
  
    ImageView userpic;
    private static final int GalleryPick = 1;
    private static final int CAMERA_REQUEST = 100;
    private static final int STORAGE_REQUEST = 200;
    private static final int IMAGEPICK_GALLERY_REQUEST = 300;
    private static final int IMAGE_PICKCAMERA_REQUEST = 400;
    String cameraPermission[];
    String storagePermission[];
    Uri imageuri;
  
    TextView click;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        // Here we are initialising 
        // the text and image View
        click = findViewById(R.id.click);
        userpic = findViewById(R.id.set_profile_image);
  
        // allowing permissions of gallery and camera
        cameraPermission = new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE};
        storagePermission = new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE};
  
        // After clicking on text we will have 
        // to choose whether to
        // select image from camera and gallery
        click.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showImagePicDialog();
            }
        });
    }
  
    private void showImagePicDialog() {
        String options[] = {"Camera", "Gallery"};
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Pick Image From");
        builder.setItems(options, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                if (which == 0) {
                    if (!checkCameraPermission()) {
                        requestCameraPermission();
                    } else {
                        pickFromGallery();
                    }
                } else if (which == 1) {
                    if (!checkStoragePermission()) {
                        requestStoragePermission();
                    } else {
                        pickFromGallery();
                    }
                }
            }
        });
        builder.create().show();
    }
  
    // checking storage permissions
    private Boolean checkStoragePermission() {
        boolean result = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == (PackageManager.PERMISSION_GRANTED);
        return result;
    }
  
    // Requesting  gallery permission
    private void requestStoragePermission() {
        requestPermissions(storagePermission, STORAGE_REQUEST);
    }
  
    // checking camera permissions
    private Boolean checkCameraPermission() {
        boolean result = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == (PackageManager.PERMISSION_GRANTED);
        boolean result1 = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == (PackageManager.PERMISSION_GRANTED);
        return result && result1;
    }
  
    // Requesting camera permission
    private void requestCameraPermission() {
        requestPermissions(cameraPermission, CAMERA_REQUEST);
    }
  
    // Requesting camera and gallery
    // permission if not given
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case CAMERA_REQUEST: {
                if (grantResults.length > 0) {
                    boolean camera_accepted = grantResults[0] == PackageManager.PERMISSION_GRANTED;
                    boolean writeStorageaccepted = grantResults[1] == PackageManager.PERMISSION_GRANTED;
                    if (camera_accepted && writeStorageaccepted) {
                        pickFromGallery();
                    } else {
                        Toast.makeText(this, "Please Enable Camera and Storage Permissions", Toast.LENGTH_LONG).show();
                    }
                }
            }
            break;
            case STORAGE_REQUEST: {
                if (grantResults.length > 0) {
                    boolean writeStorageaccepted = grantResults[0] == PackageManager.PERMISSION_GRANTED;
                    if (writeStorageaccepted) {
                        pickFromGallery();
                    } else {
                        Toast.makeText(this, "Please Enable Storage Permissions", Toast.LENGTH_LONG).show();
                    }
                }
            }
            break;
        }
    }
  
    // Here we will pick image from gallery or camera
    private void pickFromGallery() {
        CropImage.activity().start(MainActivity.this);
    }
  
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE) {
            CropImage.ActivityResult result = CropImage.getActivityResult(data);
            if (resultCode == RESULT_OK) {
                Uri resultUri = result.getUri();
                Picasso.with(this).load(resultUri).into(userpic);
            }
        }
    }
}

输出：

Github链接： https : //github.com/Anni1123/CropImage

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