调用摄像头拍照or利用外部存储文件设置头像

• 摄像头直接上代码，就是些api的调用
• 从相册中读取图片需要利用系统提供的provider来获取到该图片的路径，android 8 后强制使用这种方法。

public class CameraTestActivity extends AppCompatActivity implements View.OnClickListener {
    public static final int TAKE_PHOTO = 1;
    public static final int CHOOSE_PHOTO = 2;

    private ImageView avaterImage;
    private Button takePhotoButton;
    private Button choosePhotoButton;
    private Uri imageUri;

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

    private void init() {
        avaterImage = findViewById(R.id.image_avatar);
        takePhotoButton = findViewById(R.id.button_camera);
        choosePhotoButton = findViewById(R.id.button_album);

        takePhotoButton.setOnClickListener(this);
        choosePhotoButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.button_camera:
                File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
                try {
                    if (outputImage.exists()) {
                        outputImage.delete();
                    }
                    outputImage.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                //second parameter can be any unique string?
                imageUri = FileProvider.getUriForFile(
                        this,
                        "com.example.crane.mufirstline.cameratestactivity.fileprovider",
                        outputImage);
                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(intent, TAKE_PHOTO);
                break;
            case R.id.button_album:
                if (this.checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    this.requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 3);
                } else {
                    openAlbum()
                }
            default:
                break;

        }
    }

    private void openAlbum() {
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent, CHOOSE_PHOTO);
    }

    private void handleImage(Intent data) {
        String imgPath = null;
        Uri uri = data.getData();
        if (DocumentsContract.isDocumentUri(this, uri)) {
            //if the type is document, than handle it using doc id
            if ("com.android.provides.media.documents".equals(uri.getAuthority())) {
                String docId = DocumentsContract.getDocumentId(uri);
                String id = docId.split(":")[1];
                String selection = MediaStore.Images.Media._ID + "=" + id;
                imgPath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
            }
        }
        if (imgPath != null && !imgPath.isEmpty()) {
            displayImg(imgPath);
        }
    }


    private String getImagePath(Uri uri, String selection) {
        String path = null;
        Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }

    private void displayImg(String imgPath) {
        if (imgPath != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(imgPath);
            avaterImage.setImageBitmap(bitmap);
        } else {
            Log.w("lyh", "null path!!");
        }
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    try {
                        InputStream inputStream = getContentResolver().openInputStream(imageUri);
                        Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                        avaterImage.setImageBitmap(bitmap);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                }
                break;
            case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    if(null == data){
                        break;
                    }
                    handleImage(data);
                }
                break;
            default:
                break;
        }
    }
}