【Android -- 相机】调用摄像头拍照 & 选择照片

效果图

现在很多应用中都会要求用户上传一张图片来作为头像，首先我在这接收使用相机拍照和在相册中选择图片。接下来先上效果图：

实现代码

1. 布局文件：

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

    <Button
        android:id="@+id/btn_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/iv_picture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"/>
</LinearLayout>

2. MainActivity.java逻辑代码：

public class MainActivity extends AppCompatActivity {
    public static final int TAKE_PHOTO = 1;
    public static final int CHOOSE_PHOTO = 2;
    private Button mTakePhoto, mChoosePhoto;
    private ImageView picture;
    private Uri imageUri;

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

        mTakePhoto = (Button) findViewById(R.id.btn_take_photo);
        mChoosePhoto = (Button) findViewById(R.id.choose_from_album);
        picture = (ImageView) findViewById(R.id.iv_picture);

        mTakePhoto.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_image.jpg");

                try {
                    if (outputImage.exists()) {
                        outputImage.delete();
                    }
                    outputImage.createNewFile();

                } catch (Exception e) {
                    e.printStackTrace();
                }

                if (Build.VERSION.SDK_INT >= 24) {
                    imageUri = FileProvider.getUriForFile(MainActivity.this,
                            "com.gyq.cameraalbumtest.fileprovider", outputImage);
                } else {
                    imageUri = Uri.fromFile(outputImage);
                }

                //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);
            }
        });

        mChoosePhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                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();
                }
            }
        });
    }

    //打开相册
    private void openAlbum() {
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent, CHOOSE_PHOTO);
    }

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

        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    try {
                        Bitmap bm = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                        picture.setImageBitmap(bm);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }

                }
                break;
            case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    if (Build.VERSION.SDK_INT >= 19) {  //4.4及以上的系统使用这个方法处理图片；
                        handleImageOnKitKat(data);
                    } else {
                        handleImageBeforeKitKat(data);  //4.4及以下的系统使用这个方法处理图片
                    }
                }
            default:
                break;
        }
    }

    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();
        }
    }

    /**
     * 4.4及以上的系统使用这个方法处理图片
     *
     * @param data
     */
    @TargetApi(19)
    private void handleImageOnKitKat(Intent data) {
        String imagePath = null;
        Uri uri = data.getData();
        if (DocumentsContract.isDocumentUri(this, uri)) {
            //如果document类型的Uri,则通过document来处理
            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/piblic_downloads"), Long.valueOf(docID));

                imagePath = getImagePath(contentUri, null);

            }

        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            //如果是content类型的uri，则使用普通方式使用
            imagePath = getImagePath(uri, null);
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {
            //如果是file类型的uri，直接获取路径即可
            imagePath = uri.getPath();

        }

        displayImage(imagePath);
    }
}

3. 清单文件：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.gyq.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: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:authorities="com.gyq.cameraalbumtest.fileprovider"
            android:name="android.support.v4.content.FileProvider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data android:name="android.support.FILE_PROVIDER_PATHS"
                       android:resource="@xml/file_paths"/>
        </provider>

    </application>

</manifest>

4. xml 文件夹中的文件

<?xml version = "1.0" encoding = "utf-8"?>
    <paths xmlns:android = "http://schemas.android.com/apk/res/android">
        <external-path name = "my_images" path = ""></external-path>
    </paths>

OK，完成收工。请继续关注我的博客。谢谢！