- 运行结果如下：
2017-04-13_16-20-51.gif
第一步：搭建界面布局
第二步：在Activity中实现功能
public class MainActivity extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
private ImageView picture;
private Uri imageUri;
public static final int CHOOSE_PHOTO = 2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_main);
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) {
//创建file对象，用于储存拍照后的图片，getExternalCacheDir() : 将照片存放在手机的关联缓存目录下
File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
try {
if (outputImage.exists()) {
outputImage.delete();
}
outputImage.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
if (Build.VERSION.SDK_INT >= 24) {
//如果系统版本大于7.0，调用FileProvider的getUriForFile()方法将File对象转换成一个封装过的Uri对象
//getUriForFile()参数说明
//第一个参数：Context对象
//第二个参数：任意唯一的字符串
//第三个参数：创建的File对象
imageUri = FileProvider.getUriForFile(MainActivity.this, "com.example.cameraalbumtest.fileprovider", outputImage);
} else {
//否则，调用Uri的fromFile()方法将File对象转换成Uri对象
imageUri = Uri.fromFile(outputImage);
}
//启动相机程序
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
//设定图片的输出地址
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
//使用startActivityForResult()启动Intent时，Intent结束后会有结果返回到onActivityResult()方法中。
startActivityForResult(intent, TAKE_PHOTO);
}
});
//从相册中选择照片逻辑
final Button chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//如果未授权
if (ContextCompat.checkSelfPermission(MainActivity.this, WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
//发起授权询问
ActivityCompat.requestPermissions(MainActivity.this, new String[]{ WRITE_EXTERNAL_STORAGE }, 1);
} else {
//如果已授权，直接打开相册
openAlbum();
}
}
});
}
///打开相册的方法
private void openAlbum() {
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
startActivityForResult(intent, CHOOSE_PHOTO);
}
///用户选择完授权询问后调用
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode) {
case 1:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
//如果用户选择授权，打开相册
openAlbum();
} else {
//如果用户拒绝，弹出提示框
Toast.makeText(this, "获取相册失败，你拒绝了授权请求", Toast.LENGTH_SHORT).show();
}
break;
default:
break;
}
}
//Activity跳转之后再返回时调用
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case TAKE_PHOTO:
if (resultCode == RESULT_OK) {
//如果拍照成功
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 (resultCode == 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及以下系统使用这个方法处理图片
handleImageBeforeKitkat(data);
}
}
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.provides.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，直接获取图片的路径即可
imagePath = uri.getPath();
}
//根据图片路径显示图片
displayImage(imagePath);
}
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;
}
//设置图片
private void displayImage(String imagePath) {
if (imagePath != null) {
Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
picture.setImageBitmap(bitmap);
} else {
Toast.makeText(this,"获取图片失败",Toast.LENGTH_SHORT).show();
}
}
}
第三步：在Manifest添加权限声明