Android 数据传递-通过全局变量传递数据

 Ø在Activity之间数据传递中还有一种比较实用的方式，就是全局对象，实用J2EE的读者来说都知道Java Web的四个作用域，

 

这四个作用域从小到大分别是Page、Request、Session和Application，其中Application域在应用程序的任何地方都可以使用

 

和访问，除非是Web服务器停止，Android中的全局对象非常类似于Java Web中的Application域，除非是Android应用程序清

 

除内存，否则全局对象将一直可以访问。

 

Ø案例一

 

package com.android.myapp;

import android.R.integer;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class Main extends Activity {
    /** Called when the activity is first created. */
	private Button button;
	private MyApp myApp;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        button = (Button)this.findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				myApp = (MyApp)getApplication();
				myApp.setName("jack");//修改之后的名称
				Intent intent = new Intent(Main.this,OtherActivity.class);
				startActivity(intent);
			}
		});
    }
}

 

   

package com.android.myapp;

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

public class OtherActivity extends Activity {

	private MyApp myApp;
	private TextView textView;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.other);
		textView = (TextView)this.findViewById(R.id.msg);
		myApp = (MyApp)getApplication();
		textView.setText("-appname-->>"+myApp.getName());
	}
}

 

 

package com.android.myapp;

import android.app.Application;

public class MyApp extends Application {

	public String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public void onCreate() {
		// TODO Auto-generated method stub
		super.onCreate();
		setName("张三");
	}
}