如何在安卓中抓取一个视图的截图并保存到图库？
在本文中，我们将捕获视图的截图，并将图像存储在图库中。下面给出了一个示例视频，以了解我们将在本文中做什么。注意，我们将使用 Kotlin 语言来实现这个项目。
分步实施
第一步:创建新项目
要在安卓工作室创建新项目，请参考如何在安卓工作室创建/启动新项目。请注意，选择科特林作为编程语言
步骤 2:使用 activity_main.xml 文件
转到 activity_main.xml 文件，参考以下代码。下面是 activity_main.xml 文件的代码。注意它有一个材料卡片视图，id 为卡片 _ 视图，我们将在本文中截图这个视图。
可扩展标记语言
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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:id="@+id/parentLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
tools:context=".MainActivity">
<com.google.android.material.card.MaterialCardView
android:id="@+id/card_View"
android:layout_width="match_parent"
android:layout_height="300dp"
android:layout_margin="20dp"
android:elevation="10dp"
app:cardBackgroundColor="@color/black"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:layout_width="match_parent"
android:layout_height="200dp"
android:scaleType="center"
android:src="@drawable/gfg" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="Geeks For Geeks"
android:textColor="@color/white"
android:textSize="20sp"
android:textStyle="bold" />
</LinearLayout>
</com.google.android.material.card.MaterialCardView>
<Button
android:id="@+id/btn_capture"
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_marginTop="20dp"
android:backgroundTint="#0F9D58"
android:text="Capture View"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@id/card_View" />
</androidx.constraintlayout.widget.ConstraintLayout>
第三步。在清单中添加权限。
转到 AndroidManifest.xml 文件和以下代码。它有两个权限读取和写入外部存储。在应用程序标签中，它有安卓系统:usesCleartextTraffic =“true”。
可扩展标记语言
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.geeksforgeeks.captureview">
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"
tools:ignore="ScopedStorage" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.CaptureView"
android:usesCleartextTraffic="true">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
第 4 步:使用 MainActivity.kt 文件
转到 MainActivity.kt 文件，参考以下代码。下面是 MainActivity.kt 文件的代码。代码中添加了注释，以更详细地理解代码。
我的锅
import android.Manifest
import android.content.ContentValues
import android.graphics.Bitmap
import android.graphics.Canvas
import android.net.Uri
import android.os.Build
import android.os.Bundle
import android.os.Environment
import android.provider.MediaStore
import android.util.Log
import android.view.View
import android.widget.Button
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.cardview.widget.CardView
import androidx.core.app.ActivityCompat
import java.io.File
import java.io.FileOutputStream
import java.io.OutputStream
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// write permission to access the storage
ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE), 1)
ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE), 1)
// this is the card view whose screenshot
// we will take in this article
// get the view using fin view bt id
val cardView = findViewById<CardView>(R.id.card_View)
// on click of this button it will capture
// screenshot and save into gallery
val captureButton = findViewById<Button>(R.id.btn_capture)
captureButton.setOnClickListener {
// get the bitmap of the view using
// getScreenShotFromView method it is
// implemented below
val bitmap = getScreenShotFromView(cardView)
// if bitmap is not null then
// save it to gallery
if (bitmap != null) {
saveMediaToStorage(bitmap)
}
}
}
private fun getScreenShotFromView(v: View): Bitmap? {
// create a bitmap object
var screenshot: Bitmap? = null
try {
// inflate screenshot object
// with Bitmap.createBitmap it
// requires three parameters
// width and height of the view and
// the background color
screenshot = Bitmap.createBitmap(v.measuredWidth, v.measuredHeight, Bitmap.Config.ARGB_8888)
// Now draw this bitmap on a canvas
val canvas = Canvas(screenshot)
v.draw(canvas)
} catch (e: Exception) {
Log.e("GFG", "Failed to capture screenshot because:" + e.message)
}
// return the bitmap
return screenshot
}
// this method saves the image to gallery
private fun saveMediaToStorage(bitmap: Bitmap) {
// Generating a file name
val filename = "${System.currentTimeMillis()}.jpg"
// Output stream
var fos: OutputStream? = null
// For devices running android >= Q
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
// getting the contentResolver
this.contentResolver?.also { resolver ->
// Content resolver will process the contentvalues
val contentValues = ContentValues().apply {
// putting file information in content values
put(MediaStore.MediaColumns.DISPLAY_NAME, filename)
put(MediaStore.MediaColumns.MIME_TYPE, "image/jpg")
put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_PICTURES)
}
// Inserting the contentValues to
// contentResolver and getting the Uri
val imageUri: Uri? = resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues)
// Opening an outputstream with the Uri that we got
fos = imageUri?.let { resolver.openOutputStream(it) }
}
} else {
// These for devices running on android < Q
val imagesDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES)
val image = File(imagesDir, filename)
fos = FileOutputStream(image)
}
fos?.use {
// Finally writing the bitmap to the output stream that we opened
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, it)
Toast.makeText(this , "Captured View and saved to Gallery" , Toast.LENGTH_SHORT).show()
}
}
}
输出:
Github 回购T2这里T5】
