android基础1

HelloAndroid.java代码

package com.studio.android;
import android.app.Activity;
import android.app.AlertDialog;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class HelloAndroid extends Activity {
    /** Called when the activity is first created. */
   private Button btnShow,btnClear;
   private EditText edtInput;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btnShow=(Button)findViewById(R.id.btnShow);//控件与代码绑定
        btnClear=(Button)findViewById(R.id.btnClear);//控件与代码绑定
        edtInput=(EditText)findViewById(R.id.edtInput);//控件与代码绑定
       //设置按钮监听器
        btnShow.setOnClickListener(new ClickListener());//使用点击事件
        btnClear.setOnClickListener(new ClickListener());//使用点击事件
    }

 //接着下面写个类实现OnClickListener接口
 private final class  ClickListener implements OnClickListener
    {
        public void onClick(View v)
        {
            if(v==btnShow)
            {
                new AlertDialog.Builder(HelloAndroid.this)
                .setIcon(android.R.drawable.ic_dialog_alert)
                .setTitle("Information")
                .setMessage(edtInput.getText())
                .show();
            }
            else if(v==btnClear)
            {
                edtInput.setText("HelloAndroid");
            }
        }
    }
}

UI布局代码main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<EditText android:text="EditText01" android:layout_height="wrap_content" android:layout_width="fill_parent" android:id="@+id/edtInput"></EditText>
<LinearLayout android:id="@+id/LinearLayout01" android:layout_height="wrap_content" android:layout_width="fill_parent" android:gravity="center">
<Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Show" android:id="@+id/btnShow"></Button>
<Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Clear" android:id="@+id/btnClear"></Button>
</LinearLayout>
</LinearLayout>

运行图：