eclipse安卓helloworld程序显示问题

Question

初次用安卓AVD
但是结果什么都没有显示

代码：
package com.example.third;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity{
public void oncreate(Bundle saveInstanceState){
super.onCreate(saveInstanceState);
TextView tv = new TextView(this);
tv.setText("Hello world");
setContentView(tv);
}
}

结果：
[2014-03-18 17:52:22 - Third] ------------------------------
[2014-03-18 17:52:22 - Third] Android Launch!
[2014-03-18 17:52:22 - Third] adb is running normally.
[2014-03-18 17:52:22 - Third] Performing com.example.third.MainActivity activity launch
[2014-03-18 17:52:22 - Third] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'AVD1.1'
[2014-03-18 17:52:22 - Third] Uploading Third.apk onto device 'emulator-5554'
[2014-03-18 17:52:24 - Third] Installing Third.apk...
[2014-03-18 17:52:55 - Third] Success!
[2014-03-18 17:52:55 - Third] Starting activity com.example.third.MainActivity on device emulator-5554

程序显示就是一片空白
求前辈多多指教

Answer 1

推荐你了解一下android的目录结构，在这里，setContentView()括号里面的应该对应的是一个*.xml的文件，就是android的界面布局文件，所以我们在setContentView()中会填写R.layout.activity_main之类的界面布局文件，所以，你以上的代码在setContentView中出现了错误，自然不会出现helloworld，所以正确的代码是setContentView(R.layout.activity_main);其次，申明一个TextView，但是这个TextView必须在activity_main.xml文件中存在，所以在TextView对象赋值时应该是TextView tv = this.(activity_main.xml文件中对应的TextView的id)，然后对TextView.Text进行赋值，然后进行编译和运行，才会有结果