Android入门：基本控件（一）

概述 android的界面编程和swimg有很多类似的地方，几乎android的控件都在swimg出现过，在单个activity里编程一般只要修改源文件和main.xml。解释直接写在代码里。 1 Button main.xml <? xml version ="1.0" encoding ="utf-8" ?>
< LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent"
android:orientation ="vertical" >

< TextView
android:id ="@+id/MyTextView"
android:layout_width ="fill_parent"
android:layout_height ="wrap_content" />
< Button
android:id ="@+id/MyButton"
android:text ="点击产生随机数"
android:layout_width ="fill_parent"
android:layout_height ="wrap_content" />

</ LinearLayout >
ButtonActivity package me.chendd.button;

import java.util.Random;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class AndroidButtonActivity extends Activity {
/** Called when the activity is first created. */
private TextView MyTextview = null;
private Button MyButton = null;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MyTextview = (TextView)findViewById(R.id.MyTextView);
MyButton = (Button)findViewById(R.id.MyButton);
// 添加监听器
MyButton.setOnClickListener( new ButtonListener());
}
// 内部类实现
class ButtonListener implements OnClickListener {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// 产生随机数
String str = new Random().nextInt()+"";
MyTextview.setText(str);
}

}
}

2 ImageButton
main.xml <? xml version ="1.0" encoding ="utf-8" ?>
< LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent"
android:orientation ="vertical" >

< TextView
android:layout_width ="fill_parent"
android:layout_height ="wrap_content" />
< ImageButton
android:id ="@+id/MyImageButton"
android:layout_width ="wrap_content"
android:layout_height ="wrap_content"
android:text ="点击切换图片" />

</ LinearLayout >
ImageButton package me.chendd.imagebutton;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageButton;

public class AndroidImageButtonActivity extends Activity {
/** Called when the activity is first created. */
private ImageButton MyImageButton = null;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MyImageButton = (ImageButton) findViewById(R.id.MyImageButton);
MyImageButton.setOnTouchListener( new OnTouchListener(){

@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
if(event.getAction() == MotionEvent.ACTION_DOWN) {
// 注意此处v和MyImageButton都可以
MyImageButton.setBackgroundResource(R.drawable.ic_launcher);
} else if(event.getAction() == MotionEvent.ACTION_UP) {
MyImageButton.setBackgroundResource(R.drawable.icon);
}
return true;
}
});
}
}
3 EditText main.xml
<? xml version ="1.0" encoding ="utf-8" ?>
< LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent"
android:orientation ="vertical" >

< TextView
android:layout_width ="fill_parent"
android:layout_height ="wrap_content"
android:text ="@string/hello" />




< EditText
android:id ="@+id/et"
android:layout_width ="fill_parent"
android:layout_height ="wrap_content"
android:singleLine ="true"
android:text ="@string/hello" />

</ LinearLayout >
EditTextActivity package me.chendd.edittext;

import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;

public class AndroidEditTextActivity extends Activity {
/** Called when the activity is first created. */
private EditText et = null;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
et = (EditText) findViewById(R.id.et);
}
}

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