使用Android系统的默认的图片裁剪器

前提条件

权限

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />

文件提供者

<provider
	android:name="androidx.core.content.FileProvider"
	android:authorities="${applicationId}.provider"
	android:exported="false"
	android:grantUriPermissions="true">
	<meta-data
		android:name="android.support.FILE_PROVIDER_PATHS"
		android:resource="@xml/file_paths" />
</provider>

xml

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path
        name="download"
        path="Download/" />
    <external-path
        name="pictures"
        path="Pictures/" />
    <cache-path
        name="cache"
        path="." />
</paths>

cache: 代表的是别名
.: 代表的是context.cacheDir这个目录，即/data/data/<package-name>/cache

实现ActivityResultContract抽象类

CropContract.kt

package edu.tyut.helloktorfit.contract

import android.app.Activity
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.content.pm.ResolveInfo
import android.net.Uri
import android.os.Environment
import android.provider.MediaStore
import android.util.Log
import androidx.activity.result.contract.ActivityResultContract
import androidx.core.content.FileProvider
import java.io.File

private const val TAG: String = "CropContract"

internal class CropContract internal constructor(
    private val context: Context
): ActivityResultContract<Uri, Uri?>() {

    private val outputUri = FileProvider.getUriForFile(
        context, "${context.packageName}.provider", File(
            Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
            "${System.currentTimeMillis()}.jpg"
        )
    )

    override fun createIntent(
        context: Context,
        input: Uri
    ): Intent {

        val intent = Intent("com.android.camera.action.CROP").setDataAndType(input, "image/*")
            .setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
            .putExtra(MediaStore.EXTRA_OUTPUT, outputUri)
            .putExtra("aspectX", 1)
            .putExtra("aspectY", 1)
            .putExtra("return-data", false)

        context.packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY)
            .forEach { resolveInfo: ResolveInfo ->
                Log.i(TAG, "PhotoCard -> packageName: ${resolveInfo.activityInfo.packageName}")
                context.grantUriPermission(
                    resolveInfo.activityInfo.packageName,
                    outputUri,
                    Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
                )
            }


        return intent
    }


    override fun parseResult(
        resultCode: Int,
        intent: Intent?
    ): Uri? {
        Log.i(TAG, "parseResult -> resultCode: $resultCode, intent: $intent, outputUri: $outputUri")
        intent?.extras?.keySet()?.forEach {
            Log.i(TAG, "parseResult -> key: $it, value: ${intent.extras?.get(it)}")
        }
        return if (resultCode == Activity.RESULT_OK && intent != null) {
            intent.data?.apply {
                context.revokeUriPermission(this, Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
            } ?: run {
                context.revokeUriPermission(outputUri, Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
                outputUri
            }
        } else {
            null
        }
    }
}

清单文件声明查询

<queries>
	<!-- 声明你想查询的 Intent -->
	<intent>
		<action android:name="com.android.camera.action.CROP" />
		<data android:mimeType="image/*" />
	</intent>

	<!-- 也可以指定某些包 -->
	<!-- <package android:name="com.android.camera" /> -->
</queries>

应用

package edu.tyut.helloktorfit.ui.screen

import android.content.Context
import android.content.pm.PackageManager
import android.graphics.BitmapFactory
import android.net.Uri
import android.os.Build
import android.util.Log
import androidx.activity.compose.ManagedActivityResultLauncher
import androidx.activity.compose.rememberLauncherForActivityResult
import androidx.activity.result.PickVisualMediaRequest
import androidx.activity.result.contract.ActivityResultContracts
import androidx.compose.foundation.Image
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.SnackbarHostState
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.asImageBitmap
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.unit.dp
import androidx.core.app.ActivityOptionsCompat
import androidx.core.content.ContextCompat
import androidx.core.content.FileProvider
import androidx.core.graphics.drawable.toBitmap
import androidx.core.graphics.drawable.toDrawable
import edu.tyut.helloktorfit.contract.CropContract
import edu.tyut.helloktorfit.ui.theme.RoundedCornerShape10
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.launch
import java.io.File
import java.io.InputStream

private const val TAG: String = "CropScreen"

@Composable
internal fun CropScreen(
    modifier: Modifier,
    snackBarHostState: SnackbarHostState,
) {
    val context: Context = LocalContext.current
    var imageUri: Uri by remember {
        mutableStateOf(value = Uri.EMPTY)
    }
    val coroutineScope: CoroutineScope = rememberCoroutineScope()
    val permissions: Array<String> = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
        arrayOf(android.Manifest.permission.READ_MEDIA_IMAGES)
    } else {
        arrayOf(android.Manifest.permission.READ_EXTERNAL_STORAGE)
    }
    val permissionsLauncher: ManagedActivityResultLauncher<Array<String>, Map<String, @JvmSuppressWildcards Boolean>> = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.RequestMultiplePermissions()
    ) { map: Map<String, @JvmSuppressWildcards Boolean> ->
        coroutineScope.launch {
            snackBarHostState.showSnackbar("获取权限${if (map.values.all { it }) "成功" else "失败"}")
        }
    }
    val cropLauncher = rememberLauncherForActivityResult(
        contract = CropContract(context = context)
    ) { uri: Uri? ->
        Log.i(TAG, "cropLauncher -> uri: $uri")
        imageUri = uri!!
    }
    val launcher: ManagedActivityResultLauncher<PickVisualMediaRequest, Uri?> = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.PickVisualMedia()
    ) { uri: Uri? ->
        Log.i(TAG, "launcher -> uri: $uri, mimeType: ${context.contentResolver.getType(uri!!)}")
        val cacheImageUri: Uri = FileProvider.getUriForFile(context, "${context.packageName}.provider", File(context.cacheDir, "tmp_img_${System.currentTimeMillis()}.jpg"))
        context.contentResolver.openInputStream(uri)?.use { inputStream: InputStream ->
            context.contentResolver.openOutputStream(cacheImageUri)?.use { outputStream ->
                inputStream.copyTo(out = outputStream)
            }
        }
        cropLauncher.launch(cacheImageUri)
    }
    Column(
        modifier = Modifier.fillMaxSize()
    ) {
        Text(
            text = "裁剪图片",
            Modifier
                .padding(top = 10.dp)
                .background(color = Color.Black, shape = RoundedCornerShape10)
                .padding(all = 5.dp)
                .clickable {
                    if (permissions.any {
                            ContextCompat.checkSelfPermission(
                                context,
                                it
                            ) != PackageManager.PERMISSION_GRANTED
                        }) {
                        permissionsLauncher.launch(input = permissions)
                        return@clickable
                    }
                    val request = PickVisualMediaRequest.Builder()
                        .setMediaType(ActivityResultContracts.PickVisualMedia.ImageOnly)
                        .build()
                    launcher.launch(input = request, options = ActivityOptionsCompat.makeBasic())
                },
            color = Color.White
        )
        Image(
            bitmap = try {
                context.contentResolver.openInputStream(imageUri).use { inputStream: InputStream? ->
                    BitmapFactory.decodeStream(inputStream).asImageBitmap()
                }
            } catch (e: Exception) {
                Log.e(TAG, "CropScreen -> error: ${e.message}", e)
                0xFFBB11AA.toInt().toDrawable().toBitmap(width = 100, height = 100).asImageBitmap()
            },
            contentDescription = "裁剪图片结果",
            modifier = Modifier.fillMaxSize()
        )
    }

}

缺点

下面代码有两个缺点

context.contentResolver.openInputStream(imageUri).use { inputStream: InputStream? ->
	BitmapFactory.decodeStream(inputStream).asImageBitmap()
}

性能低
大图OOM

posted @ 2025-07-19 00:09 爱情丶眨眼而去阅读(13) 评论(0) 收藏举报

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安卓开发工程师

使用Android系统的默认的图片裁剪器

使用Android系统的默认的图片裁剪器

前提条件

实现ActivityResultContract抽象类

应用

缺点

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