Android 6.0及以上版本如何实现从图库中选取图片和拍照功能

XML 代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >

    <Button
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="takePhone"
        android:text="拍照"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="choosePhone"
        android:text="相册选择"
        />

    <ImageView
        android:id="@+id/image"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        />
</LinearLayout>

JAVA 代码：

public class MainActivity extends AppCompatActivity {
    private ImageView imageView;
    private static final int CROP_PHOTO = 2;
    private static final int REQUEST_CODE_PICK_IMAGE=3;
    private static final int MY_PERMISSIONS_REQUEST_CALL_PHONE = 6;
    private static final int MY_PERMISSIONS_REQUEST_CALL_PHONE2 = 7;
    private File output;
    private Uri imageUri;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
    }

    void initView(){

        imageView=(ImageView)findViewById(R.id.image);
    }

    public void takePhone(View view){

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)
        {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_CALL_PHONE2);

        }else {

            takePhoto();
        }
    }

    public void choosePhone(View view){

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)
        {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_CALL_PHONE2);

        }else {

            choosePhoto();
        }
    }

    /**
     * 拍照
     */
    void takePhoto(){
        /**
         * 最后一个参数是文件夹的名称，可以随便起
         */
        File file=new File(Environment.getExternalStorageDirectory(),"拍照");

        if(!file.exists()){

            file.mkdir();
        }
        /**
         * 这里将时间作为不同照片的名称
         */
        output=new File(file,System.currentTimeMillis()+".jpg");

        /**
         * 如果该文件夹已经存在，则删除它，否则创建一个
         */
        try {
            if (output.exists()) {

                output.delete();
            }
            output.createNewFile();
        } catch (Exception e) {
            e.printStackTrace();
        }
        /**
         * 隐式打开拍照的Activity，并且传入CROP_PHOTO常量作为拍照结束后回调的标志
         */
        imageUri = Uri.fromFile(output);
        Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        startActivityForResult(intent, CROP_PHOTO);

    }

    /**
     * 从相册选取图片
     */
    void choosePhoto(){
        /**
         * 打开选择图片的界面
         */
        Intent intent = new Intent(Intent.ACTION_PICK);
        intent.setType("image/*");//相片类型
        startActivityForResult(intent, REQUEST_CODE_PICK_IMAGE);

    }

    public void onActivityResult(int req, int res, Intent data) {
        switch (req) {
            /**
             * 拍照的请求标志
             */
            case CROP_PHOTO:
                if (res==RESULT_OK) {
                    try {
                        /**
                         * 该uri就是照片文件夹对应的uri
                         */
                        Bitmap bit = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                        imageView.setImageBitmap(bit);

                    } catch (Exception e) {

                        Toast.makeText(this,"程序崩溃",Toast.LENGTH_SHORT).show();
                    }
                }
                else{

                }

                break;
            /**
             * 从相册中选取图片的请求标志
             */

            case REQUEST_CODE_PICK_IMAGE:
                if (res == RESULT_OK) {
                    try {
                        /**
                         * 该uri是上一个Activity返回的
                         */
                        Uri uri = data.getData();
                        Bitmap bit = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
                        imageView.setImageBitmap(bit);
                    } catch (Exception e) {

                        e.printStackTrace();
                        Toast.makeText(this,"程序崩溃",Toast.LENGTH_SHORT).show();
                    }
                }
                else{

                }
                break;

            default:
                break;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults)
    {

        if (requestCode == MY_PERMISSIONS_REQUEST_CALL_PHONE)
        {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
            {
                takePhoto();

            } else
            {
                Toast.makeText(MainActivity.this, "Permission Denied", Toast.LENGTH_SHORT).show();
            }
        }

        if (requestCode == MY_PERMISSIONS_REQUEST_CALL_PHONE2)
        {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
            {
                choosePhoto();

            } else
            {
                Toast.makeText(MainActivity.this, "Permission Denied", Toast.LENGTH_SHORT).show();
            }
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}