Android实现调用摄像头,选择本地照片的功能

末蓝、 2022-04-06 08:18 283阅读 0赞

首先我们看布局代码的文件：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >
        <Button
            android:id="@+id/bu_1"
            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="chose from Album"/>
        <ImageView
            android:id="@+id/picture"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"/>
    </LinearLayout>

图中有两个按钮,一个是用来启动照相机的,另一个是用来选择本地照片的,还有一个ImageView控件,是用来显示照片的

然后就是主函数中的代码：

package com.example.pc_ly.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.provider.DocumentsContract;
    import android.provider.MediaStore;
    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.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.Toast;
    
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.util.concurrent.Callable;
    
    import static android.R.attr.handle;
    
    public class MainActivity extends AppCompatActivity {
        public static final int TAKE_PHOTO=1;
        public static final int CHOOSE_PHOTO=2;
        private ImageView picture;
        private Uri imageUri;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            Button button=(Button)findViewById(R.id.bu_1);
            picture=(ImageView)findViewById(R.id.picture);
            Button choose=(Button)findViewById(R.id.choose_from_album);
            choose.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {//确认是否有权限开启
                    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();
                    }
                }
            });
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    File outputImage=new File(getExternalCacheDir(),"output_image.jpg");//用于存放摄像头拍摄的照片
                    try{
                        if (outputImage.exists()){
                            outputImage.delete();
                        }
                        outputImage.createNewFile();
                    }catch (IOException e){
                        e.printStackTrace();
                    }
                    if (Build.VERSION.SDK_INT>=24){//根据android的版本对URI执行操作
                        imageUri= FileProvider.getUriForFile(MainActivity.this,"com.example.pc_ly.cameraalbumtest.fileprovider",outputImage);}
                    else{imageUri=Uri.fromFile(outputImage);
                    }
                    Intent intent=new Intent("android.media.action.IMAGE_CAPTURE");//系统会找到能够找到能响应这个intent程序去执行
                    intent.putExtra(MediaStore.EXTRA_OUTPUT,imageUri);
                    startActivityForResult(intent,TAKE_PHOTO);
                }
            });
        }
        @Override
        protected void onActivityResult(int requestCode,int resultCode,Intent data){//如果拍照成功，则会将照片显示在容器中
            switch (requestCode){
                case TAKE_PHOTO:
                    if(resultCode==RESULT_OK){
                        try{
                            Bitmap bitmap= BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                            picture.setImageBitmap(bitmap);
                        }catch (FileNotFoundException e){
                            e.printStackTrace();
                        }
                    }
                    break;
                case CHOOSE_PHOTO:
                    if(resultCode==RESULT_OK){
                        //判断手机版本号
                        if(Build.VERSION.SDK_INT>=19){
                            handleImageOnKitKat(data);
                        }
                        else{
                            handleImageBeforeKitKat(data);
                        }
                    }
                default:
                    break;
            }
        }
        public void openAlbum(){
            Intent intent=new Intent("android.intent.action.GET_CONTENT");
            intent.setType("image/*");
            startActivityForResult(intent,CHOOSE_PHOTO);//打开相册
        }
        public void onRequestPermissionResult(int requestCode,String[] permissions,int[] grantResults){//看是否权限已经打开
            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;
                default:
            }
        }
        @TargetApi(19)
        private void handleImageOnKitKat(Intent data){//根据版本对uri进行解析
            String imagePath=null;
            Uri uri=data.getData();
            if(DocumentsContract.isDocumentUri(this,uri)){
                //如果是document类型的Uri，则通过document id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/public_downloads"),Long.valueOf(docId));
                    imagePath=getImagePath(contentUri,null);
                }
                else if("content".equalsIgnoreCase(uri.getScheme())){
                    imagePath=getImagePath(uri,null);
                }
                else if("file".equalsIgnoreCase(uri.getScheme())){
                    imagePath=uri.getPath();
                }
            }
        }
        private void handleImageBeforeKitKat(Intent data){//老版本的解析
            Uri uri=data.getData();
            String imagePath=getImagePath(uri,null);
            displayImage(imagePath);
        }
        private String getImagePath(Uri uri,String selection){//获取路径
            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;
        }
        private void displayImage(String imagePath){//展示照片
            if(imagePath!=null){
                Bitmap bitmap=BitmapFactory.decodeFile(imagePath);
                picture.setImageBitmap(bitmap);
            }
            else{
                Toast.makeText(this,"faild to get image",Toast.LENGTH_SHORT).show();
            }
        }
    }

最后还有一个要注意一个重要的东西, 要申明一下权限, 如下图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdmFfX2xpeW9uZw_size_16_color_FFFFFF_t_70][]

上面的注释已经写得很清楚了啦,我就不一一解释了，下面来看效果图：

![20181208234002237.jpg][]

运行之后是这个界面，然后我们点击take photo按钮,就可以打开照相机啦,如下图：

![20181208234121637.jpg][]

然后我们点击CHOSE FROM ALBUM按钮,就可以选择照片文件啦：

![20181208234309395.jpg][]

好啦,这次就到这里啦，有什么疑问的话欢迎和我留言呀

邮箱：2321591758@qq.com

其他博客的链接：

[Github个人网站][Github]      [知乎][Link 1]      [简书][Link 2]

欢迎各位访问哦，这次就到这里啦！

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdmFfX2xpeW9uZw_size_16_color_FFFFFF_t_70]: /images/20220406/b448edf62bf84d1886ddf3657eb07bc3.png
[20181208234002237.jpg]: /images/20220406/a1d45c64b4484bd38af2b50b1ecdbf26.png
[20181208234121637.jpg]: /images/20220406/d18b386c96cd4ec199ebf2c895c2e472.png
[20181208234309395.jpg]: /images/20220406/f9887d8edeaf431ca10cacbd6f482b8d.png
[Github]: http://www.imlowliness.club
[Link 1]: https://www.zhihu.com/people/li-yong-ji-suan-ji/activities
[Link 2]: https://www.jianshu.com/u/6c1284ced65e