編輯:關於Android編程
MainActivity如下:
[java]
package cn.testchangevar;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.app.Activity;
/**
* Demo描述:
* Java中的傳值及其改變
*
*/
public class MainActivity extends Activity {
private int id=7;
private Person mPerson;
private Button mButton;
private String mString;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
private void init(){
mString=new String("OOOOO");
mPerson=new Person("xx", 22);
mButton=(Button) findViewById(R.id.button);
mButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
System.out.println("111 id="+id);
System.out.println("111 mString="+mString);
System.out.println("111 mPerson.getAge()="+mPerson.getAge());
System.out.println("=========================");
Util.change(id);
Util.change(mString);
Util.change(mPerson);
System.out.println("=========================");
System.out.println("222 id="+id);
System.out.println("222 mString="+mString);
System.out.println("222 mPerson.getAge()="+mPerson.getAge());
}
});
}
}
package cn.testchangevar;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.app.Activity;
/**
* Demo描述:
* Java中的傳值及其改變
*
*/
public class MainActivity extends Activity {
private int id=7;
private Person mPerson;
private Button mButton;
private String mString;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
private void init(){
mString=new String("OOOOO");
mPerson=new Person("xx", 22);
mButton=(Button) findViewById(R.id.button);
mButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
System.out.println("111 id="+id);
System.out.println("111 mString="+mString);
System.out.println("111 mPerson.getAge()="+mPerson.getAge());
System.out.println("=========================");
Util.change(id);
Util.change(mString);
Util.change(mPerson);
System.out.println("=========================");
System.out.println("222 id="+id);
System.out.println("222 mString="+mString);
System.out.println("222 mPerson.getAge()="+mPerson.getAge());
}
});
}
}
Util如下:
[java]
package cn.testchangevar;
public class Util {
//不可以改變.因為int屬於基礎類型
public static void change(int i){
i=9527;
System.out.println("has been changed i="+i);
}
//可以改變.傳遞的是對象
public static void change(Person person){
person.setAge(88);
System.out.println("has been changed string="+person);
}
//不可以改變.雖然String也是對象,但是較為特殊
public static void change(String string){
string="XXXXX";
System.out.println("has been changed string="+string);
}
}
package cn.testchangevar;
public class Util {
//不可以改變.因為int屬於基礎類型
public static void change(int i){
i=9527;
System.out.println("has been changed i="+i);
}
//可以改變.傳遞的是對象
public static void change(Person person){
person.setAge(88);
System.out.println("has been changed string="+person);
}
//不可以改變.雖然String也是對象,但是較為特殊
public static void change(String string){
string="XXXXX";
System.out.println("has been changed string="+string);
}
}
Person如下:
[java]
package cn.testchangevar;
public class Person {
private String name;
private int age;
public Person(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + "]";
}
}
package cn.testchangevar;
public class Person {
private String name;
private int age;
public Person(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + "]";
}
}
main.xml如下:
[html]
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world"
android:layout_centerInParent="true"
/>
</RelativeLayout>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world"
android:layout_centerInParent="true"
/>
</RelativeLayout>
效果圖 功能簡介 這個頁面用到了添加圖層,添加覆蓋物,覆蓋物的事件處理,地圖的旋轉、縮放,高德定位,地圖分層顯隱,關鍵詞搜索等功能。 本篇博
前言:為什麼要了解系統Activity,Service,,BroadCastReceiver,ContentProvider的啟動流程,這是一個對於即將理解插件中的四大組
效果如下圖:1. MainActivity.javapackage com.example.chartview;import java.util.ArrayList;im
我用GridView來顯示一些字符串,而字符串的長度是不固定的,然後就遇到問題了:有時字符重疊,有時顯示不全,有時兩種問題同時出現。見下圖: 圖一 GridView顯示重