Question

我刚刚开始自学android开发，并且在这个基本的hello world应用程序中遇到了错误。

我尝试搜索，但对我来说一切都像中文。

这是我正在关注的教程：https://developer.android.com/training/basics/firstapp/starting-activity

，这是我的错误的屏幕截图： [我将在下面添加代码] [1]：https://i.stack.imgur.com/Xm1tg.png

<code>
public class DisplayMessageActivity extends AppCompatActivity {

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

// Get the Intent that started this activity and extract the string
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

// Capture the layout's TextView and set the string as its text
TextView textView = findViewById(R.id.textView);
textView.setText(message);//on this line i get an error under "message"
</code>

Answer 1

在onCreate（）方法中移动该代码，例如：

public class DisplayMessageActivity extends AppCompatActivity {

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

        // Get the Intent that started this activity and extract the string
        Intent intent = getIntent();
        String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

        // Capture the layout's TextView and set the string as its text
        TextView textView = findViewById(R.id.textView);
        textView.setText(message);
    }
}

Answer 2

您需要在onCreate()内移动以下代码

// Get the Intent that started this activity and extract the string
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

// Capture the layout's TextView and set the string as its text
TextView textView = findViewById(R.id.textView);
textView.setText(message);//on this line i get an error under "message"

错误：未知类：“消息”-如何解决？

2 个答案: