从相机获取图片
xml
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<uses-permission android:name="android.permission.CAMERA" />
java
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private static final int REQUEST_CODE_TAKE = 1;
java
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public void takePhoto(View view) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
doTake();
} else {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CODE_TAKE);
}
}
java
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@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == REQUEST_CODE_TAKE) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
doTake();
} else {
Toast.makeText(this, "你没有获得摄像头权限", Toast.LENGTH_SHORT).show();
}
}
}
java
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register = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
if (result != null) {
if (result.getResultCode() == Activity.RESULT_OK) {
try {
InputStream inputStream = getContentResolver().openInputStream(imageUri);
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
// 转成Base64字符串 方便上传到服务器
imageBase64 = ImageUtil.imageToBase64(bitmap);
ivAvatar.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
});
- 在 onCreate 中注册 Activity 返回结果回调
java
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private void doTake() {
File imageTemp = new File(getExternalCacheDir(), "imageOut.jpeg");
if (imageTemp.exists()) {
imageTemp.delete();
}
try {
imageTemp.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
imageUri = Uri.fromFile(imageTemp);
if (Build.VERSION.SDK_INT > 24) {
imageUri = FileProvider.getUriForFile(this, "com.example.study_android.fileprovider", imageTemp);
}
Intent intent = new Intent();
intent.setAction("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
register.launch(intent);
}
xml
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<provider
android:authorities="com.example.study_android.fileprovider"
android:name="androidx.core.content.FileProvider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/files"/>
</provider>
xml
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<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path
name="image_path"
path="/"/>
</paths>
从相册获取图片
xml
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<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
java
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public void choosePhoto(View view) {
// 权限WRITE_EXTERNAL_STORAGE表示同时授予程序对SD卡读和写的能力。
if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
openAlbum();
} else {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CODE_CHOOSE);
}
}
private void openAlbum() {
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
registerAlbum.launch(intent);
}
java
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registerAlbum = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
if (result != null) {
if (result.getResultCode() == Activity.RESULT_OK) {
Intent intent = result.getData();
if (Build.VERSION.SDK_INT < 19) {
handleImageBeforeApi19(intent);
} else {
handleImageOnApi19(intent);
}
}
}
});
java
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private void handleImageBeforeApi19(Intent data) {
Uri uri = data.getData();
String imagePath = getImagePath(uri, null);
displayImage(imagePath);
}
java
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/*
* 因为Android系统从4.4版本开始，选取相册中的图片不再返回图片真实的Uri了，而是一个封装过的Uri
* 因此如果是4.4版本以上的手机就需要对这个Uri进行解析才行
* */
@TargetApi(19)
private void handleImageOnApi19(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 documentId = DocumentsContract.getDocumentId(uri);
if (TextUtils.equals(uri.getAuthority(), "com.android.providers.media.documents")) {
String id = documentId.split(":")[1];
String selection = MediaStore.Images.Media._ID + "=" + id;
imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
} else if (TextUtils.equals(uri.getAuthority(), "com.android.providers.downloads.documents")) {
if (documentId != null && documentId.startsWith("msf:")) {
resolveMSFContent(uri);
return;
}
Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(documentId));
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
imagePath = uri.getPath();
}
displayImage(imagePath);
}
java
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private void resolveMSFContent(Uri uri) {
File file = new File(getCacheDir(), "temp_file" + getContentResolver().getType(uri).split("/")[1]);
try {
InputStream inputStream = getContentResolver().openInputStream(uri);
OutputStream outputStream = new FileOutputStream(file);
byte[] buffer = new byte[4 * 1024];
int read;
while ((read = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, read);
}
outputStream.flush();
Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
ivAvatar.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
java
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// 获取图片真实路径
@SuppressLint("Range")
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;
}
案例代码