调用系统的Camera和相册/压缩照片

来源：互联网发布：奥卡福知乎编辑：程序博客网时间：2024/05/22 15:36

调用系统的Camera

1.这只是简单的调用一下摄像头，然后拍一张照片。这个命令是基于Intent的，需要在setAction中添加调用摄像头的语句，然后利用Intent.putExtra将得到的照片存放到file里
最后复写onActivityResult，将拍下来的照片显示到ImageView上

2.需要权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

3.有的手机需要不能将所照的图片显示在ImageView上，是因为所照的照片比较大，需要将其压缩，就可以正常显示了，不过这里的压缩方法是在原文件的基础上进行的压缩，压缩后的文件会替换掉原文件

调用手机相册

1.从相册中选择图片，需要创建一个Intent对象，将他的action设置为Intent.ACTION_GET_CONTENT，然后设置类型为“iamge/*”，最后调用startActivityForResult()方法，就可以打开相册程序选择照片

2.在onActivityResult方法中，利用data来得到所选择的照片，从而将照片显示到ImageView上去，这里就不能用压缩了，因为这个压缩方法会将原来的图片替换为压缩过后的图片，因此不建议使用该压缩方法

代码实现

public class MainActivity extends AppCompatActivity implements View.OnClickListener{    private Button mBtnCamera;    private Button mBtnPicture;    private ImageView mImage;    private File file;    public static final int CAMERA=0x88;    public static final int PICTTURE=0x66;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mImage = (ImageView) findViewById(R.id.image_camera);        mBtnCamera = (Button) findViewById(R.id.button_camera);        mBtnPicture = (Button) findViewById(R.id.button_picture);        mBtnCamera.setOnClickListener(this);        mBtnPicture.setOnClickListener(this);    }    @Override    public void onClick(View v) {        switch (v.getId()){            case R.id.button_camera:                Intent intent=new Intent();                intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);//Standard Intent action that can be sent to have the camera application capture an image and return it.                file=new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");//创建一个文件                try {                    file.createNewFile();                } catch (IOException e) {                    e.printStackTrace();                }                intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));//将拍下来的照片，存放到file路径下                startActivityForResult(intent, CAMERA);                break;            case R.id.button_picture://                Intent intentPicture=new Intent("android.intent.action.GET_CONTENT");                Intent intentPicture=new Intent(Intent.ACTION_GET_CONTENT);                intentPicture.setType("image/*");                startActivityForResult(intentPicture,PICTTURE);                break;        }    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        super.onActivityResult(requestCode, resultCode, data);        //判断requestCode和resultCode是否是符合情况，如果符合就将拍下来的照片显示在ImageView上            if (resultCode==RESULT_OK){                switch (requestCode){                    case CAMERA:                        ImageZip.zipImage(file.getAbsolutePath());                        mImage.setImageURI(Uri.fromFile(file));                        break;                    case PICTTURE:                        Uri uri=data.getData();                        mImage.setImageURI(uri);                        break;                }            }    }}

压缩照片代码

在源文件的基础上进行压缩，替换掉源文件

public  class ImageZip {    public static   void zipImage(String savePath) {        BitmapFactory.Options options = new BitmapFactory.Options();        options.inJustDecodeBounds = true;        BitmapFactory.decodeFile(savePath, options);        options.inSampleSize = computeInitialSampleSize(options, 480, 480 * 960);        options.inJustDecodeBounds = false;        Bitmap bitmap = BitmapFactory.decodeFile(savePath, options);        try {            FileOutputStream fos = new FileOutputStream(savePath);            bitmap.compress(Bitmap.CompressFormat.JPEG, 90, fos);            fos.flush();            fos.close();        } catch (IOException e) {            e.printStackTrace();        }        bitmap.recycle();        bitmap = null;        System.gc();    }    public static int computeSampleSize(BitmapFactory.Options options,                                 int minSideLength, int maxNumOfPixels) {        int initialSize = computeInitialSampleSize(options, minSideLength,                maxNumOfPixels);        int roundedSize;        if (initialSize <= 8) {            roundedSize = 1;            while (roundedSize < initialSize) {                roundedSize <<= 1;            }        } else {            roundedSize = (initialSize + 7) / 8 * 8;        }        return roundedSize;    }    private static int computeInitialSampleSize(BitmapFactory.Options options,                                         int minSideLength, int maxNumOfPixels) {        double w = options.outWidth;        double h = options.outHeight;        int lowerBound = (maxNumOfPixels == -1) ? 1 : (int) Math.ceil(Math                .sqrt(w * h / maxNumOfPixels));        int upperBound = (minSideLength == -1) ? 128 : (int) Math.min(                Math.floor(w / minSideLength), Math.floor(h / minSideLength));        if (upperBound < lowerBound) {            // return the larger one when there is no overlapping zone.            return lowerBound;        }        if ((maxNumOfPixels == -1) && (minSideLength == -1)) {            return 1;        } else if (minSideLength == -1) {            return lowerBound;        } else {            return upperBound;        }    }}

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