一手遮天 Android - 设计模式: Singleton（单例模式）

项目地址 https://github.com/webabcd/AndroidDemo
作者 webabcd

一手遮天 Android - 设计模式: Singleton（单例模式）

示例如下:

/designpattern/Singleton.java

/**
 * 单例模式的调用示例
 */

package com.webabcd.androiddemo.designpattern;

import android.os.SystemClock;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import com.webabcd.androiddemo.R;

public class Singleton extends AppCompatActivity {

    private TextView mTextView1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_designpattern_singleton);

        mTextView1 = findViewById(R.id.textView1);

        sample();
    }

    private void sample() {
        mTextView1.append(String.valueOf(SingletonPattern.getInstance().getTimestamp()));

        SystemClock.sleep(100);
        mTextView1.append("\n");

        mTextView1.append(String.valueOf(SingletonPattern.getInstance().getTimestamp()));
    }
}

\designpattern\SingletonPattern.java

/**
 * 单例模式
 */

package com.webabcd.androiddemo.designpattern;

import android.os.SystemClock;

public class SingletonPattern {
    private static SingletonPattern instance = null;

    public synchronized static SingletonPattern getInstance() {
        if (instance == null) {
            instance = new SingletonPattern();
        }
        return instance;
    }

    private final long mTimestamp;

    private SingletonPattern() {
        mTimestamp = SystemClock.elapsedRealtime();
    }

    public long getTimestamp() {
        return mTimestamp;
    }
}

/layout/activity_designpattern_singleton.xml

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

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

项目地址 https://github.com/webabcd/AndroidDemo
作者 webabcd