Android使用相机实现拍照存储及展示功能详解

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

<application
        ...>
        <activity
            android:name=".MainActivity"
            android:exported="true">
            ...
        </activity>
        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="com.zhiyiyi.login.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/files" />
        </provider>
    </application>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="20dp"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <ImageView
            android:id="@+id/image"
            android:layout_width="200dp"
            android:layout_height="200dp" />
        <ImageButton
            android:id="@+id/imagebtn"
            android:layout_width="100dp"
            android:layout_height="60dp"
            android:src="@android:drawable/ic_menu_camera" />
    </LinearLayout>
</LinearLayout>

class MainActivity : AppCompatActivity() {
    private lateinit var photoUri: Uri
    private lateinit var btn: ImageButton
    private lateinit var image: ImageView
    ...
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    // 初始化两个组件
    btn = findViewById(R.id.imagebtn)
    image = findViewById(R.id.image)
    btn.setOnClickListener {
        // 新建一个文件，他的位置位于外存根目录下，且文件名为outputimage.jpg
        val file = File(getExternalFilesDir(null), "outputimage.jpg")
        // 为避免输出流错误，需要捕获错误
        try {
            file.createNewFile()
        } catch (e: IOException) {
            e.printStackTrace()
        }
        // 使用FileProvider.getUriForFile获取相片存储的URI
        // 参数一：上下文
        // 参数二：我们之前在androidmanifest中注册provider时自定义的authorities
        // 参数三：欲转换成uri路径的文件
        photoUri = FileProvider.getUriForFile(
            this@MainActivity,
            "com.zhiyiyi.login.fileprovider",
            file
        )
        // 使用隐式intent唤醒相机
        val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
        // 传入photouri，以保证我们的照片存储到指定位置
        intent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri)
        // 老样子，不解释
        startActivityForResult(intent, 1)
    }
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    when (requestCode) {
        1 -> {
            if (resultCode == RESULT_OK) {
                try {
                    // 使用bitmap解码文件
                    val bitmap =
                        BitmapFactory.decodeStream(contentResolver.openInputStream(photoUri))
                    // 将图片展示在imageview上面
                    image.setImageBitmap(bitmap)
                } catch (e: FileNotFoundException) {
                    e.printStackTrace()
                }
            }
        }
    }
}

package com.zhiyiyi.login
import android.content.Intent
import android.graphics.BitmapFactory
import android.net.Uri
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.IBinder
import android.provider.MediaStore
import android.util.Log
import android.widget.ImageButton
import android.widget.ImageView
import androidx.core.content.FileProvider
import com.zhiyiyi.login.databinding.ActivityMainBinding
import java.io.File
import java.io.FileNotFoundException
import java.io.IOException
import java.net.URI
import kotlin.math.log
class MainActivity : AppCompatActivity() {
    private lateinit var photoUri: Uri
    private lateinit var btn: ImageButton
    private lateinit var image: ImageView
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        btn = findViewById(R.id.imagebtn)
        image = findViewById(R.id.image)
        btn.setOnClickListener {
            Log.d("fuck", "tnnd就是拍不了照")
            val file = File(getExternalFilesDir(null), "outputimage.jpg")
            Log.d("fuck", file.absolutePath)
            try {
                file.createNewFile()
            } catch (e: IOException) {
                e.printStackTrace()
            }
            photoUri = FileProvider.getUriForFile(
                this@MainActivity,
                "com.zhiyiyi.login.fileprovider",
                file
            )
            val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
            intent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri)
            startActivityForResult(intent, 1)
        }
    }
    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        when (requestCode) {
            1 -> {
                if (resultCode == RESULT_OK) {
                    try {
                        val bitmap =
                            BitmapFactory.decodeStream(contentResolver.openInputStream(photoUri))
                        image.setImageBitmap(bitmap)
                    } catch (e: FileNotFoundException) {
                        e.printStackTrace()
                    }
                }
            }
        }
    }
}