一、前言
引用《第一行代码》8.3调用摄像头和相册
二、调用摄像头
1、Android7.0之后加入了provider，首先Android Studio中添加provider的相关代码。
- 在AndroidManifest注册provider
- 创建file_paths.xml文件:res-->xml（新建）-->file.paths（新建）。
注：空值就表示将整个SD卡进行共享，当然也可以仅共享我们存放output_image.jpg这张图片的路径。
2、相机拍照需要获取写入内存的权限，在AndroidManifest中添加权限。在调用相机时询问并获取权限。
- 添加权限
- 询问并获取权限
if (ContextCompat.checkSelfPermission(TakeAPhoto.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(TakeAPhoto.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
} else {
takePhoto();
}
- 重写获取权限的结果，进行相关操作
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.
PERMISSION_GRANTED) {
//需要进行的操作
} else {
Toast.makeText(TakeAPhoto.this, "您取消了申请权限", Toast.LENGTH_LONG).show();
}
}
}
- 附上有关权限的相关文章
重新认识Android权限
3、调用相机的相关代码。
public class TakeAPhoto extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
private ImageView picture;
private Uri imageUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.take_a_photo);
final Button takePhoto = (Button) findViewById(R.id.take_photo);
picture = (ImageView) findViewById(R.id.picture);
takePhoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 获取权限
if (ContextCompat.checkSelfPermission(TakeAPhoto.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(TakeAPhoto.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
} else {
takePhoto();
}
}
});
}
private void takePhoto() {
// 创建File对象，用于存储拍照后的图片。可根据自己需求创建对应的文件夹
File outputImage = new File(getExternalCacheDir(),
"output_image.jpg");//这里可以用当前时间戳来命名。 System.currentTimeMillis() + ".jpg" ;
try {
if (outputImage.exists()) {
outputImage.delete();
}
outputImage.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
if (Build.VERSION.SDK_INT >= 24) {
imageUri = FileProvider.getUriForFile(TakeAPhoto.this,
"com.example.administrator.drawable.fileprovider", outputImage);
} else {
imageUri = Uri.fromFile(outputImage);
}
// 启动相机程序
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
startActivityForResult(intent, TAKE_PHOTO);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case TAKE_PHOTO:
if (resultCode == RESULT_OK) {
try {
// 将拍摄的照片显示出来
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
picture.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
break;
default:
break;
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.
PERMISSION_GRANTED) {
takePhoto();
} else {
Toast.makeText(TakeAPhoto.this, "您取消了申请权限", Toast.LENGTH_LONG).show();
}
}
}
}
打开相机思路：添加Provider，添加权限，调用相机打开拍照，打开前判断手机版本是否高于23(7.0)，获取对应的Uri。在进行操作，在重写的返回结果中显示图片
三、打开相册
1、获取权限（AndroidManifest中申明，在打开相册前询问并授权），同上
2、打开相册相关代码
public class TakeAPhoto extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
public static final int CHOOSE_PHOTO = 2;
private ImageView picture;
private Uri imageUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.take_a_photo);
.....
Button chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
.....
chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (ContextCompat.checkSelfPermission(TakeAPhoto.this,
Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.
PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(TakeAPhoto.this, new
String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
} else {
openAlbum();
}
}
});
}
private void openAlbum() {
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
startActivityForResult(intent, CHOOSE_PHOTO); // 打开相册
}
..........
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case TAKE_PHOTO:
if (resultCode == RESULT_OK) {
try {
// 将拍摄的照片显示出来
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
picture.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
break;
case CHOOSE_PHOTO:
if (requestCode == RESULT_OK) {
// 判断手机系统版本号
if (Build.VERSION.SDK_INT >= 19) {
// 4.4及以上系统使用这个方法处理图片
handleImageOnKitKat(data);
} else {
// 4.4以下系统使用这个方法处理图片
handleImageBeforeKitKat(data);
}
}
break;
default:
break;
}
}
@TargetApi(19)
private void handleImageOnKitKat(Intent data) {
String imagePath = null;
Uri uri = data.getData();
if (DocumentsContract.isDocumentUri(this, uri)) {
// 如果是document类型的Uri，则通过document id处理
String docId = DocumentsContract.getDocumentId(uri);
if ("com.android.providers.media.documents".equals(uri.getAuthority())) {
String id = docId.split(":")[1]; // 解析出数字格式的id
String selection = MediaStore.Images.Media._ID + "=" + id;
imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
} else if ("com.android.providers.downloads.documents".equals(uri.
getAuthority())) {
Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));
imagePath = getImagePath(contentUri, null);
}
} else if ("content".equalsIgnoreCase(uri.getScheme())) {
// 如果是content类型的Uri，则使用普通方式处理
imagePath = getImagePath(uri, null);
} else if ("file".equalsIgnoreCase(uri.getScheme())) {
// 如果是file类型的Uri，直接获取图片路径即可
imagePath = uri.getPath();
}
displayImage(imagePath); // 根据图片路径显示图片
}
private void handleImageBeforeKitKat(Intent data) {
Uri uri = data.getData();
String imagePath = getImagePath(uri, null);
displayImage(imagePath);
}
private String getImagePath(Uri uri, String selection) {
String path = null;
// 通过Uri和selection来获取真实的图片路径
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 displayImage(String imagePath) {
if (imagePath != null) {
Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
picture.setImageBitmap(bitmap);
} else {
Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.
PERMISSION_GRANTED) {
// takePhoto();
openAlbum();
} else {
Toast.makeText(TakeAPhoto.this, "您取消了申请权限", Toast.LENGTH_LONG).show();
}
}
}
}
思路：先添加权限，通过Intent打开相册选取照片，选择照片后判断手机版本是否低于4.4，在重写的返回结果中使用对应的方法进行操作（不用provider）。