android onBackPressed 按钮导航崩溃

Question

我想使用此代码制作后退导航逻辑：

backBtn.setOnClickListener(v -> {
        onBackPressed();
    });
    otherUsername.setText(otherUser.getUsername());

但似乎 onBackPressed 现在已被弃用，所以当我运行应用程序并单击后退按钮时，它工作了一段时间，但随后它会转到上一页，就像我双击它一样，当我尝试这样做时第二次应用程序将崩溃。

如何解决这个问题？

对于上下文，这是我的完整代码：

import android.os.Bundle;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

import androidx.activity.OnBackPressedCallback;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.RecyclerView;

import com.daffakhairy.easychat.model.UserModel;
import com.daffakhairy.easychat.utils.AndroidUtil;

public class ChatActivity extends AppCompatActivity {

UserModel otherUser;

EditText messageInput;
ImageButton sendMessageBtn;
ImageButton backBtn;
TextView otherUsername;
RecyclerView recyclerView;

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

    // Get UserModel
    otherUser = AndroidUtil.getUserModelFromIntent(getIntent());

    messageInput = findViewById(R.id.chat_message_input);
    sendMessageBtn = findViewById(R.id.message_send_btn);
    backBtn = findViewById(R.id.back_btn);
    otherUsername = findViewById(R.id.other_username);
    recyclerView = findViewById(R.id.chat_recycler_view);

    backBtn.setOnClickListener(v -> {
        onBackPressed();
    });
    otherUsername.setText(otherUser.getUsername());

}
}

Answer 1

从 Android API 级别 33 开始，onBackPressed() 方法已被弃用。现在推荐的方法是通过 OnBackPressedCallback 使用 OnBackPressedDispatcher。 这种方法允许您更干净地处理后退导航逻辑并避免意外行为。

解决方案：使用OnBackPressedDispatcher 您可以使用 OnBackPressedCallback 显式处理 Activity 中的后退导航。以下是您的代码的修改版本：

import android.os.Bundle;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

import androidx.activity.OnBackPressedCallback;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.RecyclerView;

import com.daffakhairy.easychat.model.UserModel;
import com.daffakhairy.easychat.utils.AndroidUtil;

public class ChatActivity extends AppCompatActivity {

    UserModel otherUser;

    EditText messageInput;
    ImageButton sendMessageBtn;
    ImageButton backBtn;
    TextView otherUsername;
    RecyclerView recyclerView;

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

        // Get UserModel
        otherUser = AndroidUtil.getUserModelFromIntent(getIntent());

        messageInput = findViewById(R.id.chat_message_input);
        sendMessageBtn = findViewById(R.id.message_send_btn);
        backBtn = findViewById(R.id.back_btn);
        otherUsername = findViewById(R.id.other_username);
        recyclerView = findViewById(R.id.chat_recycler_view);

        // Set the username
        if (otherUser != null) {
            otherUsername.setText(otherUser.getUsername());
        } else {
            otherUsername.setText("Unknown User");
        }

        // Handle back button click
        backBtn.setOnClickListener(v -> finish()); // Directly finish the `activity

        // Handle system back button using OnBackPressedDispatcher
        OnBackPressedCallback callback = new OnBackPressedCallback(true) {
            @Override
            public void handleOnBackPressed() {
                // Custom back navigation logic
                finish(); // End the activity
            }
        };

        // Add the callback to the dispatcher
        getOnBackPressedDispatcher().addCallback(this, callback);
    }
}

使用 OnBackPressedCallback：

向OnBackPressedDispatcher注册以拦截后退按钮按下。