再android7.0中相机操作需要动态申请权限,在点击打开相机按钮时要先判断权限,没有权限要申请,有权限再操作,同时在申请权限的回调方法中也要判断是否有权限,有权限的话再调用打开相机的方法

package test.img.com.myimgtest.activity;

import android.Manifest;
import android.annotation.TargetApi;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.media.ExifInterface;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;

import test.img.com.myimgtest.R;
import test.img.com.myimgtest.util.ImgPretreatment;

public class ORCActivity888 extends AppCompatActivity {
    public static final int TAKE_PHOTO = 1;//启动相机标识
    public static final int SELECT_PHOTO = 2;//启动相册标识
    private ImageView imageView;
    private TextView textView;
    private File outputImagepath;//存储拍完照后的图片
    private Bitmap orc_bitmap;//拍照和相册获取图片的Bitmap
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_orc);
        imageView = (ImageView) findViewById(R.id.shangchuan_img);
        textView = (TextView) findViewById(R.id.chazhi_tv);

    }

    /**
     * 打开相机
     *
     * @param view
     */
    public void xiangjiClick(View view) {
          //checkSelfPermission 检测有没有 权限
//        PackageManager.PERMISSION_GRANTED 有权限
//        PackageManager.PERMISSION_DENIED  拒绝权限
        //一定要先判断权限,再打开相机,否则会报错
        if(ActivityCompat.checkSelfPermission(this,Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){
            //权限发生了改变 true  //  false,没有权限时
            if(ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.CAMERA)){
                new AlertDialog.Builder(this).setTitle("title")
                        .setPositiveButton("ok", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                // 请求授权
                                ActivityCompat.requestPermissions(ORCActivity888.this,new String[]{Manifest.permission.CAMERA},1);
                            }
                        }).setNegativeButton("cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                             //不请求权限的操作
                    }
                }).create().show();
            }else {
                ActivityCompat.requestPermissions(ORCActivity888.this,new String[]{Manifest.permission.CAMERA},1);
            }
        }else{
            take_photo();//已经授权了就调用打开相机的方法
        }
    }

    /**
     * 打开相册
     */
    public void xiangceClick(View view) {
        select_photo();
    }

    /**
     * 拍照获取图片
     **/
    public void take_photo() {
        //获取系統版本
        int currentapiVersion = Build.VERSION.SDK_INT;
        // 激活相机
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        // 判断存储卡是否可以用,可用进行存储
        if (hasSdcard()) {
            SimpleDateFormat timeStampFormat = new SimpleDateFormat(
                    "yyyy_MM_dd_HH_mm_ss");
            String filename = timeStampFormat.format(new Date());
            outputImagepath = new File(Environment.getExternalStorageDirectory(),
                    filename + ".jpg");
            if (currentapiVersion < 24) {
                // 从文件中创建uri
                Uri uri = Uri.fromFile(outputImagepath);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
            } else {
                //兼容android7.0 使用共享文件的形式
                ContentValues contentValues = new ContentValues(1);
                contentValues.put(MediaStore.Images.Media.DATA, outputImagepath.getAbsolutePath());
                Uri uri = getApplication().getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
            }
        }
        // 开启一个带有返回值的Activity,请求码为PHOTO_REQUEST_CAREMA
        startActivityForResult(intent, TAKE_PHOTO);
    }


    /*
     * 判断sdcard是否被挂载
     */
    public static boolean hasSdcard() {
        return Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED);
    }

    /**
     * 从相册中获取图片
     */
    public void select_photo() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
        } else {
            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, SELECT_PHOTO);
    }


    /**
     * 4.4以下系统处理图片的方法
     */
    private void handleImageBeforeKitKat(Intent data) {
        Uri uri = data.getData();
        String imagePath = getImagePath(uri, null);
        displayImage(imagePath);
    }

    /**
     * 4.4及以上系统处理图片的方法
     */
    @TargetApi(Build.VERSION_CODES.KITKAT)
    private void handleImgeOnKitKat(Intent data) {
        String imagePath = null;
        Uri uri = data.getData();
        Log.d("uri=intent.getData :", "" + uri);
        if (DocumentsContract.isDocumentUri(this, uri)) {
            String docId = DocumentsContract.getDocumentId(uri);        //数据表里指定的行
            Log.d("getDocumentId(uri) :", "" + docId);
            Log.d("uri.getAuthority() :", "" + uri.getAuthority());
            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())) {
                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));
                imagePath = getImagePath(contentUri, null);
            }

        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            imagePath = getImagePath(uri, null);
        }
        displayImage(imagePath);
    }
    /**
     * 通过uri和selection来获取真实的图片路径,从相册获取图片时要用
     */
    private String getImagePath(Uri uri, String selection) {
        String path = null;
        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;
    }


    /**
     * 拍完照和从相册获取玩图片都要执行的方法(根据图片路径显示图片)
     */
    private void displayImage(String imagePath) {
        if (!TextUtils.isEmpty(imagePath)) {
            //orc_bitmap = BitmapFactory.decodeFile(imagePath);//获取图片
            orc_bitmap = comp(BitmapFactory.decodeFile(imagePath)); //压缩图片
            ImgUpdateDirection(imagePath);//显示图片,并且判断图片显示的方向,如果不正就放正
        } else {
            Toast.makeText(this, "图片获取失败", Toast.LENGTH_LONG).show();
        }
    }




    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            //打开相机后返回
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    /**
                     * 这种方法是通过内存卡的路径进行读取图片,所以的到的图片是拍摄的原图
                     */
                    displayImage(outputImagepath.getAbsolutePath());
                    Log.i("tag", "拍照图片路径>>>>" + outputImagepath);
                }
                break;
            //打开相册后返回
            case SELECT_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
                        handleImgeOnKitKat(data);
                    } else {
                        handleImageBeforeKitKat(data);
                    }
                }
                break;
            default:
                break;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case 1:
                //判断是否有权限
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    openAlbum();//打开相册
                    take_photo();//打开相机
                } else {
                    Toast.makeText(this, "你需要许可", Toast.LENGTH_LONG).show();
                }
                break;
            default:
                break;
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (orc_bitmap != null) {
            orc_bitmap.recycle();
        } else {
            orc_bitmap = null;
        }
    }


    /**
     * 质量压缩方法
     *
     * @param image
     * @return
     */
    public static Bitmap compressImage(Bitmap image) {
        if (image != null) {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            image.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法,这里100表示不压缩,把压缩后的数据存放到baos中
            int options = 100;
            while (baos.toByteArray().length / 1024 > 100) { //循环判断如果压缩后图片是否大于100kb,大于继续压缩
                baos.reset();//重置baos即清空baos
                options -= 10;//每次都减少10
                image.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%,把压缩后的数据存放到baos中

            }
            ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中
            Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//把ByteArrayInputStream数据生成图片
            return bitmap;
        } else {
            return null;
        }

    }
    //比例压缩
    private Bitmap comp(Bitmap image) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        image.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        if (baos.toByteArray().length / 1024 > 1024) {//判断如果图片大于1M,进行压缩避免在生成图片(BitmapFactory.decodeStream)时溢出
            baos.reset();//重置baos即清空baos
            image.compress(Bitmap.CompressFormat.JPEG, 50, baos);//这里压缩50%,把压缩后的数据存放到baos中
        }
        ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());
        BitmapFactory.Options newOpts = new BitmapFactory.Options();
        //开始读入图片,此时把options.inJustDecodeBounds 设回true了
        newOpts.inJustDecodeBounds = true;
        Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, newOpts);
        newOpts.inJustDecodeBounds = false;
        int w = newOpts.outWidth;
        int h = newOpts.outHeight;
        //现在主流手机比较多是800*480分辨率,所以高和宽我们设置为
        float hh = 800f;//这里设置高度为800f
        float ww = 480f;//这里设置宽度为480f
        //缩放比。由于是固定比例缩放,只用高或者宽其中一个数据进行计算即可
        int be = 1;//be=1表示不缩放
        if (w > h && w > ww) {//如果宽度大的话根据宽度固定大小缩放
            be = (int) (newOpts.outWidth / ww);
        } else if (w < h && h > hh) {//如果高度高的话根据宽度固定大小缩放
            be = (int) (newOpts.outHeight / hh);
        }
        if (be <= 0)
            be = 1;
        newOpts.inSampleSize = be;//设置缩放比例
        newOpts.inPreferredConfig = Bitmap.Config.RGB_565;//降低图片从ARGB888到RGB565
        //重新读入图片,注意此时已经把options.inJustDecodeBounds 设回false了
        isBm = new ByteArrayInputStream(baos.toByteArray());
        bitmap = BitmapFactory.decodeStream(isBm, null, newOpts);
        return bitmap;//压缩好比例大小后再进行质量压缩
    }


    //改变拍完照后图片方向不正的问题
    private void ImgUpdateDirection(String filepath) {
        int digree = 0;//图片旋转的角度
        //根据图片的URI获取图片的绝对路径
        Log.i("tag", ">>>>>>>>>>>>>开始");
        //String filepath = ImgUriDoString.getRealFilePath(getApplicationContext(), uri);
        Log.i("tag", "》》》》》》》》》》》》》》》" + filepath);
        //根据图片的filepath获取到一个ExifInterface的对象
        ExifInterface exif = null;
        try {
            exif = new ExifInterface(filepath);
            Log.i("tag", "exif》》》》》》》》》》》》》》》" + exif);
            if (exif != null) {

                // 读取图片中相机方向信息
                int ori = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);

                // 计算旋转角度
                switch (ori) {
                    case ExifInterface.ORIENTATION_ROTATE_90:
                        digree = 90;
                        break;
                    case ExifInterface.ORIENTATION_ROTATE_180:
                        digree = 180;
                        break;
                    case ExifInterface.ORIENTATION_ROTATE_270:
                        digree = 270;
                        break;
                    default:
                        digree = 0;
                        break;

                }

            }
            //如果图片不为0
            if (digree != 0) {
                // 旋转图片
                Matrix m = new Matrix();
                m.postRotate(digree);
                orc_bitmap = Bitmap.createBitmap(orc_bitmap, 0, 0, orc_bitmap.getWidth(),
                        orc_bitmap.getHeight(), m, true);
            }
            if (orc_bitmap != null) {
                imageView.setImageBitmap(orc_bitmap);
            }
        } catch (IOException e) {
            e.printStackTrace();
            exif = null;
        }
    }
}