Question

我想编写一个模块，单击按钮即可打开相机，然后单击并捕获图像。如果我不喜欢该图像，则可以将其删除并再单击一个图像，然后选择该图像，它应返回并在活动中显示该图像。问题出在我拍照时，相机应用程序崩溃了；当我从图库中拍照时，图片没有显示在图像视图中。

这是我写的脚本：


public class MainpageActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {
    final int TAKE_PICTURE = 1;
    final int ACTIVITY_SELECT_IMAGE = 2;

    ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mainpage);
        Toolbar toolbar = findViewById(R.id.toolbar);
        imageView = (ImageView)this.findViewById(R.id.imageView1);
        setSupportActionBar(toolbar);
        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setImageResource(R.drawable.ic_camera_alt_black_24dp);

        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {   RxPermissions rxPermissions = new RxPermissions(MainpageActivity.this);
                rxPermissions
                        .request(Manifest.permission.CAMERA) // ask single or multiple permission once
                        .subscribe(granted -> {
                            if (granted) {
                                selectImage();
                            } else {
                                Toast.makeText(MainpageActivity.this, "Permission of camera is denied", Toast.LENGTH_SHORT).show();
                            }
                        });


            }
        });

    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;
    }

    private void selectImage() {



        final CharSequence[] options = { "Take Photo", "Choose from Gallery","Cancel" };



        AlertDialog.Builder builder = new AlertDialog.Builder(MainpageActivity.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);
                imageView.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);
                imageView.setBackgroundDrawable(drawable);


            }
        }
    }
}

Answer 1

我认为您应该尝试添加此“ android：required =“ true”。

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

Answer 2

@Uma：请按照以下步骤操作，并更改您的代码。

步骤1-在 AndroidManifest.xml

中添加两行

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

并在清单文件的应用程序标记中添加此属性：

android:largeHeap="true"
android:hardwareAccelerated="false"

步骤-2-将lib导入到 build.gradle 文件

中

implementation 'com.karumi:dexter:4.2.0' // for handling runtime permissions

步骤-3-在您的 MainpageActivity.java

中

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    this.imageView = (ImageView)this.findViewById(R.id.imageView1);
    this.fab = (FloatingActionButton) this.findViewById(R.id.fab);

    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v)
        {
            CheckPermission();

        }
    });
}

private void CheckPermission(){
    Dexter.withActivity(this)
            .withPermissions(
                    Manifest.permission.CAMERA,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)
            .withListener(new MultiplePermissionsListener() {
                @Override
                public void onPermissionsChecked(MultiplePermissionsReport report) {
                    // check if all permissions are granted
                    if (report.areAllPermissionsGranted()) {
                        selectImage();
                    }

                    // check for permanent denial of any permission
                    if (report.isAnyPermissionPermanentlyDenied()) {
                        // permission is denied permenantly, navigate user to app settings
                    }
                }

                @Override
                public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
                    token.continuePermissionRequest();
                }
            })
            .onSameThread()
            .check();
}

private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
    new AlertDialog.Builder(MainActivity.this)
            .setMessage(message)
            .setPositiveButton("OK", okListener)
            .setNegativeButton("Cancel", null)
            .create()
            .show();
}

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;
}

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

@SuppressLint("LongLogTag")
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK) {
        if (requestCode == 1) {
            Bitmap photo = (Bitmap) data.getExtras().get("data");
            imageView.setImageBitmap(photo);
        } else if (requestCode == 2) {
            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();
            imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));
        }
    }}

希望它对您有帮助。

Answer 3

首先，您需要获得权限处理

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

此后，您可以使用此按钮来打开图库

//opening image chooser option
    choose.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_PICK);
            startActivityForResult(Intent.createChooser(intent, "Select Image"), PICK_IMAGE_REQUEST);
        }
    });

借助此功能，您可以在UI上显示图像

 @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
        Uri filePath = data.getData();

        try {
            //getting image from gallery
            bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);

            //Setting image to ImageView
            image.setImageBitmap(bitmap);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

此外，您可以将图像转换为bitmap64：

//converting image to base64 string
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.JPEG, 50, baos);
    byte[] imageBytes = baos.toByteArray();
    final String imageString = Base64.encodeToString(imageBytes, Base64.DEFAULT);

从相机或图库中拍摄图像并进行活动展示

3 个答案: