为什么 EditText 在 Ice Cream Sandwich 中保留其 Activity 的上下文 [英] Why does EditText retain its Activity's Context in Ice Cream Sandwich

问题描述

在 Ice Cream Sandwich 中，当有一个包含 EditText 的 Activity 时，即使在用户离开 Activity 之后，EditText 也会保留 Activity 的 Context.为了演示这一点，我创建了 TestLeakActivity，它分配了一个大字节数组.由于 Activity 的 Context 永远不会被垃圾回收，字节数组在堆上累积，最终导致 OutOfMemoryError.您可以使用 DDMS 堆工具观察堆的增长，您可以通过查看 Eclipse MAT 中的 HPROF 文件来跟踪对 EditText 类的未完成引用.要创建内存泄漏，请进入 LaunchActivity 并继续启动和退出 TestLeakActivity.

LaunchActivity.java

<前>包 com.example.testleakproject;导入 android.app.Activity;导入 android.content.Intent;导入 android.os.Bundle;导入 android.view.View;导入 android.view.View.OnClickListener;导入 android.view.ViewGroup;导入 android.widget.Button;导入 android.widget.TextView;公共类 LaunchActivity 扩展 Activity {@覆盖public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);Button button = new Button(this);button.setText("启动TestLeakActivity");button.setOnClickListener(new OnClickListener() {@覆盖public void onClick(View v) {意图意图 = 新意图(LaunchActivity.this, TestLeakActivity.class);开始活动(意图)；}});ViewGroup 容器 = ((ViewGroup) findViewById(android.R.id.content));container.addView(button);}}

TestLeakActivity.java

<前>包 com.example.testleakproject;导入 android.app.Activity;导入 android.os.Bundle;导入 android.view.ViewGroup;导入 android.widget.EditText;公共类 TestLeakActivity 扩展 Activity {私有字节[] mSomeBytes = 新字节[1048576];@覆盖public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);EditText editText = new EditText(this);editText.setHint("TestLeakActivity");ViewGroup 容器 = ((ViewGroup) findViewById(android.R.id.content));container.addView(editText);}}

解决方案

这是一个已知错误，将在 ICS MR1 中修复.

In Ice Cream Sandwich, when there's an Activity containing an EditText, the EditText will retain the Activity's Context even after the user leaves the Activity. To demonstrate this I've created TestLeakActivity, which allocates a large byte array. Since the Activity's Context is never garbage collected, the byte arrays accumulate on the heap, eventually causing an OutOfMemoryError. You can observe the heap growth by using the DDMS heap tool, and you can track the outstanding references to the EditText class by looking at the HPROF file in Eclipse MAT. To create memory leaks, go into LaunchActivity and just keep launching and backing out of TestLeakActivity.

LaunchActivity.java

package com.example.testleakproject;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

public class LaunchActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Button button = new Button(this);
        button.setText("Start TestLeakActivity");
        button.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(LaunchActivity.this, TestLeakActivity.class);
                startActivity(intent);
            }
        });

        ViewGroup container = ((ViewGroup) findViewById(android.R.id.content));
        container.addView(button);
    }
}

TestLeakActivity.java

package com.example.testleakproject;

import android.app.Activity;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.EditText;

public class TestLeakActivity extends Activity {
    private byte[] mSomeBytes = new byte[1048576];

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        EditText editText = new EditText(this);
        editText.setHint("TestLeakActivity");

        ViewGroup container = ((ViewGroup) findViewById(android.R.id.content));
        container.addView(editText);
    }
}

解决方案

This is a known bug, that will be fixed in ICS MR1.

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