Question

我完全遵循https://developer.android.com/training/basics/firstapp/starting-activity#java上的指南来创建我的第一个Android应用程序，但是在那里发布的代码给了我一个错误。显然没有TextView.setText（String）方法，下面的代码未编译：

    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 = (TextView)findViewById(R.id.textView);
        textView.setText(message);
    }

错误消息：无法解析符号'setText'

有人可以帮忙吗？

Answer 1

您需要执行findViewById和textView.setText(message); 内部onCreate()方法

尝试

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 = (TextView)findViewById(R.id.textView);
        textView.setText(message);
    }
}

Answer 2

尝试一下（您必须将这些行放入方法中）：

    @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 = (TextView)findViewById(R.id.textView);
        textView.setText(message);**   
     }

如何修改TextView的内容

2 个答案: