Question

我正在学习android studio，而我正在浏览＃34; MyFirstApp＆＃34;教程。但是，当我尝试运行应用程序时，我收到错误＆＃34;无法解析符号＆＃34; setText＆＃34;。这是我的代码：

package com.example.myfirstapp;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

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);
}

这应该与教程中的代码相同：https://developer.android.com/training/basics/firstapp/starting-activity.html#java

这是activity_display_message.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".DisplayMessageActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="@string/textview"
        android:textSize="14sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

我试图检查一个类似的问题，但似乎我没有做任何不同的事情：Android tutorial "Cannot resolve symbol 'setText' "任何人都可以帮助我吗？

Answer 1

此代码必须位于onCreate（）：

之内

// 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

只需公开TextView并在onCreate（）方法外部声明即可。

$order->update([
    'order_id' => $response->json['id'],
]);

return $response;

无法解析符号＆＃34; setText＆＃34;在Android Developer Tutorial网页上

2 个答案: