Question

我是android deva和java的新手。我想显示文字，但下面的代码不起作用。

DisplayText.java

package com.example.DisplayText;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

    public class DisplayText extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            TextView tv2 = (TextView) this.findViewById(R.id.thetext);
            tv2.setText("YO -- ");
            setContentView(R.layout.main);

        }
    }

main.xml中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
    <TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    android:id="@+id/thetext"
    />
</LinearLayout>

非常感谢您的帮助！：）

Answer 1

更改此代码：

public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            TextView tv2 = (TextView) this.findViewById(R.id.thetext);
            tv2.setText("YO -- ");
            setContentView(R.layout.main);

        }

这一个：

public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            TextView tv2 = (TextView) this.findViewById(R.id.thetext);
            tv2.setText("YO -- ");


        }

Answer 2

把

setContentView(R.layout.main);

之前TextView tv2 = (TextView) this.findViewById(R.id.thetext);

从main.xml访问TextView

Android：TextView无法正常工作

2 个答案: