FileProvider的拍照和打开相册功能

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.cameraalbumtest">    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:roundIcon="@mipmap/ic_launcher_round"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <provider            android:name="android.support.v4.content.FileProvider"            android:authorities="com.example.cameraalbumtest.fileprovider"            android:exported="false"            android:grantUriPermissions="true"            >            <meta-data                android:name="android.support.FILE_PROVIDER_PATHS"                android:resource="@xml/file_paths"                />        </provider>    </application></manifest>

res/xml/file_paths.xml

<?xml version="1.0" encoding="utf-8"?><paths>    <root-path name="my_images" path=""/></paths>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent">   <Button       android:id="@+id/take_photo"       android:layout_width="match_parent"       android:layout_height="wrap_content"       android:text="Take Photo"/>    <Button        android:id="@+id/choose_from_album"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="Choose From Album"/>    <ImageView        android:id="@+id/picture"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"/></LinearLayout>

MainActivity.class

public class MainActivity 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.activity_main);        final Button takePhoto = (Button) findViewById(R.id.take_photo);        picture = (ImageView) findViewById(R.id.picture);        Button chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);        takePhoto.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                //创建File对象,用于存储拍照后的照片                //安卓6.0 读写sd被称为危险权限 所以存到缓存目录 而getExternalCacheDir 就可以得到这个缓存目录                File fileDir = getExternalCacheDir();                File imageDir = new File(fileDir,"images");                if(!imageDir.exists()){                    imageDir.mkdirs();                }                File imageFile = new File(imageDir,"picture.jpg");                try{                    //判断文件是否存在                    if(imageFile.exists()){                        //文件存在就删除                        imageFile.delete();                    }                    //创建图片                    imageFile.createNewFile();                }catch (Exception e){                    e.printStackTrace();                }                if(Build.VERSION.SDK_INT >= 24){                    //如果设备版本大于7.0                    imageUri = FileProvider.getUriForFile(MainActivity.this,                            "com.example.cameraalbumtest.fileprovider",imageFile);                } else {                    imageUri = Uri.fromFile(imageFile);                }                //IMAGE_CAPTURE:图片捕获                //MediaStore:媒体商店                //EXTRA_OUTPUT:额外输出                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);                startActivityForResult(intent,TAKE_PHOTO);            }        });        chooseFromAlbum.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                if(ContextCompat.checkSelfPermission(MainActivity.this,                   Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){                   ActivityCompat.requestPermissions(MainActivity.this,                            new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);                } else {                    openAlbum();                }            }        });    }    @Override    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {        //requestCode 发出去的请求码   resultCode 返回的参数        switch (requestCode){            case 1:                if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){                    openAlbum();                } else {                    Toast.makeText(this,"You denied the permission",Toast.LENGTH_SHORT).show();                }                break;            default:                break;        }    }    private void openAlbum(){        Intent intent = new Intent("android.intent.action.GET_CONTENT");        intent.setType("image/*");        startActivityForResult(intent,CHOOSE_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 (Exception e){                        e.printStackTrace();                    }                }                break;            case CHOOSE_PHOTO:                if(resultCode == RESULT_OK){                    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);                    }                }                break;            default:                break;        }    }    private void handleImageOnKitKat(Intent data){        String imagePath = null;        Uri uri = data.getData();        //data是从相册返回的数据        //android 7.1.1        //uri == content://com.android.providers.media.documents/document/image%3A75        //uri.getAuthority() == com.android.providers.media.documents        //uri.getPath() == /document/image:75        //DocumentsContract.getDocumentId(uri) == image:75        //MediaStore.Images.Media.EXTERNAL_CONTENT_URI == content://media/external/images/media        //真实路径 path == /storage/emulated/0/Download/picture.jpg        //android4.4        //uri == content://com.android.providers.media.documents/document/image%3A28        //uri.getAuthority() == com.android.providers.media.documents        //uri.getPath() == /document/image:28        //DocumentsContract.getDocumentId(uri) == image:28        //MediaStore.Images.Media.EXTERNAL_CONTENT_URI == content://media/external/images/media        //真实路径 path == /storage/sdcard/images/picture.jpg        //相册存了图片的id，并没有存实际路径。        //Authority就是相册数据库的标识符，这里有两个数据库，他们的标识符分别为        //com.android.providers.media.documents        //com.android.providers.downloads.documents        //当点击一张照片它会返回document封装了的uri，然后进行解析出资源id，        //然后根据id在MediaStore数据库中获取真实URL路径        //判断该Uri是否是document封装过的        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];                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())){                //这个方法负责把id和contentUri连接成一个新的Uri                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);    }    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来获取真实路径        //Android系统提供了MediaScanner，MediaProvider，MediaStore等接口，并且提供了一套数据库        //表格，通过Content Provider的方式提供给用户。当手机开机或者有SD卡插拔等事件发生时，系统        //将会自动扫描SD卡和手机内存上的媒体文件，如audio，video，图片等，将相应的信息放到定义好        //的数据库表格中。在这个程序中，我们不需要关心如何去扫描手机中的文件，只要了解如何查询和使        //用这些信息就可以了。MediaStore中定义了一系列的数据表格，通过ContentResolver提供的查询        //接口，我们可以得到各种需要的信息。        //EXTERNAL_CONTENT_URI 为查询外置内存卡的，INTERNAL_CONTENT_URI为内置内存卡。        //MediaStore.Audio获取音频信息的类        //MediaStore.Images获取图片信息        //MediaStore.Video获取视频信息        Cursor cursor = getContentResolver().query(uri,null,selection,null,null);        if(cursor != null){            if(cursor.moveToNext()){                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);        }    }}

拍照

打开相册