'startActivityForResult(android.content.Intent, int)' 已弃用我该怎么办？

Question

'startActivityForResult(android.content.Intent, int)' 已弃用我该怎么办？ 这是我的二维码扫描器 android 应用程序 (java) (androidstudio) 的代码：

package com.example.wfr;

import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    private static final int REQUEST_CODE = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.qr_scanner_layout);


        //Button click event to open QR scanner
        findViewById(R.id.camera_button).setOnClickListener(v -> {
            Intent intent = new Intent(MainActivity.this, QRCodeScanner.class);
            intent.putExtra("SCAN_FORMATS", "QR_CODE");
            startActivityForResult(intent, REQUEST_CODE);
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
            if (data != null) {
                String scannedText = data.getStringExtra("com.journeyapps.barcodescanner.CaptureActivity.SCAN_RESULT");
                TextView scannedTextView = findViewById(R.id.scanned_text);
                scannedTextView.setText(scannedText);
            }
        }
    }
}

Answer 1

基本培训可在https://developer.android.com/training/basics/intents/result

以下是有关如何将现有代码转换为新代码的示例：

旧方法：

public void openSomeActivityForResult() {
    Intent intent = new Intent(this, SomeActivity.class);
    startActivityForResult(intent, 123);
}

@Override
protected void onActivityResult (int requestCode, int resultCode, Intent data) {
    if (resultCode == Activity.RESULT_OK && requestCode == 123) {
        doSomeOperations();
    }
}

新方式（Java）：

public void openSomeActivityForResult() {
    Intent intent = new Intent(this, SomeActivity.class);
    someActivityResultLauncher.launch(intent);
}

// You can do the assignment inside onAttach or onCreate, i.e, before the activity is displayed
ActivityResultLauncher<Intent> someActivityResultLauncher = registerForActivityResult(
        new ActivityResultContracts.StartActivityForResult(),
        new ActivityResultCallback<ActivityResult>() {
            @Override
            public void onActivityResult(ActivityResult result) {
                if (result.getResultCode() == Activity.RESULT_OK) {
                    // There are no request codes
                    Intent data = result.getData();
                    doSomeOperations();
                }
            }
        });

这是你的代码

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.qr_scanner_layout);


        //Button click event to open QR scanner
        findViewById(R.id.camera_button).setOnClickListener(v -> {
            Intent intent = new Intent(MainActivity.this, QRCodeScanner.class);
            intent.putExtra("SCAN_FORMATS", "QR_CODE");
             someActivityResultLauncher.launch(intent);
        });
    }

// You can do the assignment inside onAttach or onCreate, i.e, before the activity is displayed
ActivityResultLauncher<Intent> someActivityResultLauncher = registerForActivityResult(
        new ActivityResultContracts.StartActivityForResult(),
        new ActivityResultCallback<ActivityResult>() {
            @Override
            public void onActivityResult(ActivityResult result) {
                if (result.getResultCode() == Activity.RESULT_OK) {
                    // There are no request codes
                    Intent data = result.getData();
                    if (data != null) {
                String scannedText = data.getStringExtra("com.journeyapps.barcodescanner.CaptureActivity.SCAN_RESULT");
                TextView scannedTextView = findViewById(R.id.scanned_text);
                scannedTextView.setText(scannedText);
            }
                }
            }
        });
}

Answer 2

如果不推荐使用 function， 文档通常会告诉您原因以及应该使用什么：

此 function 已弃用。

此方法已被弃用，取而代之的是使用 Activity Result API，它通过ActivityResultContract和androidx.activity.result.contract.ActivityResultContracts中可用的常见意图的预构建合同带来更高的类型安全性，提供用于测试的挂钩，并允许接收结果独立于您的活动的独立的、可测试的类。 使用registerForActivityResult为ActivityResultContract传入StartActivityForResult object。

另一个答案向您展示了使用这些东西的开发人员指南并有一个示例，但是当您遇到已弃用的东西时，请务必始终查看文档 - 很少有 function 在没有任何信息的情况下被删除，有时您不需要无论如何都要担心弃用（例如，如果它只发生在最新版本的 Android 上，这意味着他们刚刚决定在将来某个时候将其删除，因为旧的 API 不再使用）