Android调用相机拍照与选择已经存在的相片
（一）.调用手机摄像头拍照：
1.布局：
<?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="拍照"
/>
<ImageView
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"/>
</LinearLayout>
2.主活动代码：
public class MainActivity 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.activity_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，用于存储拍照后的图片 File outputImage = new File(getExternalCacheDir(),"output_iamge.jpg"); //得到应用关联缓存目录，不用再进行运行时权限处理 try { if (outputImage.exists()) { outputImage.delete(); } outputImage.createNewFile(); } catch (IOException e) { e.printStackTrace(); } if (Build.VERSION.SDK_INT >= 24) { imageUri = FileProvider.getUriForFile(MainActivity.this,"com.example.cameraalbumtest.fileprovider",outputImage); //将file对象转换成封装后的uri，Android7.0后不能直接使用真实URI，会抛出FileUriExposedException异常,等下要对FileProvider内容提供器进行注册 } else { imageUri = Uri.fromFile(outputImage); //将file对象转换成本地真实路径的URI } //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 public 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(); } } default: break; }
3.在AndroidManifest.xml中注册FileProvider和声明权限：
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="com.example.cameraalbumtest.fileprovider" //和刚才FileProvider.getUriForFile()方法中的第二个参数相同
android:exported="false"
android:grantUriPermissions="true">
<meta-data //指定Uri的共享路径
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths"/> //在res目录下创建file_paths文件
</provider>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> //兼容android4.4以前访问sd的应用关联目录
4.file_paths文件：
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="my_images" path=""/>
</paths>
5.运行程序点击即按钮后：（二）在相册中选择相片：
1.布局中添加一个按钮：
<Button
android:id="@+id/choose_from_album"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="选择相片" />
2.活动中代码：
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 {
openAblum();
}
}
});
}
private void openAblum() {
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*"); //Set an explicit MIME data type
startActivityForResult(intent,CHOOSE_PHOTO); //打开相册
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int [] grantResults) {
switch(requestCode) {
case 1:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
openAblum();
} else {
Toast.makeText(this, "You denied the permission", Toast.LENGTH_SHORT).show();
}
break;
default:
}
}
@Override
public 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();
}
}
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doucument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，则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();
}
}