安卓：引用到上下文和内存泄漏 [英] Android : References to a Context and memory leaks

问题描述

我已经读，这是一个错误，内存泄漏源在Android应用程序，以保持一个长期存在引用的上下文。

但我不明白，如果它是确定创建一个看起来像这样的一个类：

 公共类助手类{
    私人上下文的背景下;

    公共助手类（上下文的背景下）{
        this.context =背景;
    }
    公共无效myHelperMethod（）{
        //使用this.context
    }
}
 

和从活动中调用它：

 公共类MyActivity延伸活动{
    公共无效的onCreate（包savedInstanceState）{
        助手类H =新助手类（本）;
        h.myHelperMethod（）;
    }

    ...
}
 

解决方案

这是好的，并不会造成内存泄漏。

当的onCreate 执行完毕， ^ h 将超出范围并符合垃圾收集。如果 ^ h 是静态的，那么你会遇到问题。仅当参考上下文会超越的上下文的生命周期本身将内存泄漏发生。一些有用的提示：

• 使用 Context.getApplicationContext（）在可能的情况。这种情况下将生活，只要你的应用程序是活的。
• 在使用静态字段和内部类时要小心。
• 通过探查检查运行应用程序泄漏。

I've read that it is a mistake and a source of memory leaks in Android application to keep a long-lived references to a Context.

But I don't understand if it is ok to create an class that looks like this one:

public class HelperClass {
    private Context context;

    public HelperClass(Context context) {
        this.context = context;
    }
    public void myHelperMethod() {
        // uses this.context
    }
}

And call it from an Activity:

public class MyActivity extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        HelperClass h = new HelperClass(this);
        h.myHelperMethod();
    }

    ...
}

解决方案

This is fine, and will not cause a memory leak.

As soon as onCreate finishes executing, h will be out of scope and become eligible for garbage collection. If h was static, then you would run into problems. Only when the reference to the context outlives the lifecycle of the context itself will a memory leak occur. A few helpful hints:

• Use Context.getApplicationContext() when possible. This context will live as long as your application is alive.
• Be careful when using static fields and inner classes.
• Run your application through a profiler to check for leaks.

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