Android开发之调用摄像头拍照

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：

接下来看代码：
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：

package com.gyq.cameraalbumtest;

import android.Manifest;
import android.annotation.TargetApi;
import android.content.ContentUris;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
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.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import java.io.File;

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！