Android开发-通过观察者设计模式刷新数据或者关闭界面

女爷i 2024-05-03 14:37 30阅读 0赞

简述：

可以用于登陆后返回到上一个界面，对界面进行刷新；

可以解决用startActivityForResult新打开的界面中返回数据难以操作的问题；

可以同时对整个项目中已经打开的多个界面同时进行数据更新，方便维护；

可以对指定界面进行指定操作，例如关闭指定界面

步骤一：

定义观察者接口:

\---------------------------------------------------------------------------------------

ObserverListener.java

package com.huwan.observermanagerdemo.clickListener;

public interface ObserverListener \{

void observerUpData(String content);

\---------------------------------------------------------------------------------------

package com.huwan.observermanagerdemo.clickListener;

SubjectListener.java

public interface SubjectListener \{

void add(ObserverListener observerListener);

void notifyObserver(String content);

void remove(ObserverListener observerListener);

\---------------------------------------------------------------------------------------

ObserverManager.java

package com.huwan.observermanagerdemo;

import com.huwan.observermanagerdemo.clickListener.ObserverListener;

import com.huwan.observermanagerdemo.clickListener.SubjectListener;

import java.util.ArrayList;

import java.util.List;

public class ObserverManager implements SubjectListener \{

private static ObserverManager observerManager;

//观察者接口集合

private List<ObserverListener> list = new ArrayList<>();

/\*\*

\* 单例

\*/

public static ObserverManager getInstance()\{

if (null == observerManager)\{

synchronized (ObserverManager.class)\{

if (null == observerManager)\{

observerManager = new ObserverManager();

return observerManager;

/\*\*

\* 加入监听队列

\*/

@Override

public void add(ObserverListener observerListener) \{

list.add(observerListener);

/\*\*

\* 通知观察者刷新数据

\*/

@Override

public void notifyObserver(String content) \{

for (ObserverListener observerListener : list)\{

observerListener.observerUpData(content);

/\*\*

\* 监听队列中移除

\*/

@Override

public void remove(ObserverListener observerListener) \{

if (list.contains(observerListener))\{

list.remove(observerListener);

\---------------------------------------------------------------------------------------

MainActivity.java

package com.huwan.observermanagerdemo;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.widget.TextView;

import com.huwan.observermanagerdemo.clickListener.ObserverListener;

public class MainActivity extends Activity implements ObserverListener \{

private TextView textView;

@Override

protected void onCreate(Bundle savedInstanceState) \{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity\_main);

// 注册监听

ObserverManager.getInstance().add(this);

textView = (TextView) findViewById(R.id.tv);

findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() \{

@Override

public void onClick(View v) \{

Intent intent = new Intent(MainActivity.this, SecondActivity.class);

startActivity(intent);

\});

@Override

public void observerUpData(String content) \{

if(("关闭第二界面，返回第一界面").equals(content))\{

textView.setText("测试了关闭第二界面，直接返回第一界面");

\}else\{

textView.setText(content);

\---------------------------------------------------------------------------------------

SecondActivity.java

package com.huwan.observermanagerdemo;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.TextView;

import com.huwan.observermanagerdemo.clickListener.ObserverListener;

public class SecondActivity extends Activity implements ObserverListener \{

@Override

protected void onCreate(Bundle savedInstanceState) \{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity\_second);

// 注册监听

ObserverManager.getInstance().add(this);

findViewById(R.id.btn2).setOnClickListener(new View.OnClickListener() \{

@Override

public void onClick(View v) \{

ObserverManager.getInstance().notifyObserver("观察者，请刷新信息！");

finish();

\});

findViewById(R.id.btn2\_tothree).setOnClickListener(new View.OnClickListener() \{

@Override

public void onClick(View v) \{

startActivity(new Intent(SecondActivity.this,ThreeActivity.class));

\});

@Override

public void observerUpData(String content) \{

if(("关闭第二界面，返回第一界面").equals(content))\{

finish();

\---------------------------------------------------------------------------------------

ThreeActivity.java

package com.huwan.observermanagerdemo;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

public class ThreeActivity extends Activity\{

@Override

protected void onCreate(Bundle savedInstanceState) \{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity\_three);

findViewById(R.id.btn3).setOnClickListener(new View.OnClickListener() \{

@Override

public void onClick(View v) \{

ObserverManager.getInstance().notifyObserver("关闭第二界面，返回第一界面");

finish();

\});

// 注册监听

//ObserverManager.getInstance().add(this);

// @Override

// public void observerUpData(String content) \{

// \}

\---------------------------------------------------------------------------------------

// 备注：在界面关闭的时候一定要销毁观察者，否则会内存溢出，很重要！！！  
ObserverManager.getInstance().remove(this);

Demo样例下载：[http://www.huwan.xin/Source/AppPackage/ZIP/Android/ObserverManagerDemo.rar][http_www.huwan.xin_Source_AppPackage_ZIP_Android_ObserverManagerDemo.rar]

更多内容请访问：[www.huwan.xin][]

[http_www.huwan.xin_Source_AppPackage_ZIP_Android_ObserverManagerDemo.rar]: http://www.huwan.xin/Source/AppPackage/ZIP/Android/ObserverManagerDemo.rar
[www.huwan.xin]: http://www.huwan.xin