WebView-存在的内存泄漏

0. Notice - earlier version

• 要使用WebView不造成内存泄漏，首先应该做的就是不能在xml中定义webview节点，而是在需要的时候动态生成。即：可以在使用WebView的地方放置一个LinearLayout类似ViewGroup的节点，然后在要使用WebView的时候，动态生成即：

1. WebView mWebView = new WebView(getApplicationgContext());
2. LinearLayout mll = findViewById(R.id.xxx);
3. mll.addView(mWebView);

然后一定要在onDestroy()方法中显式的调用:

1. protected void onDestroy() {
2. super.onDestroy();
3. mWebView.removeAllViews();
4. mWebView.destroy()
5. }

注意： new WebView(getApplicationgContext()) ;必须传入ApplicationContext如果传入Activity的Context的话，对内存的引用会一直被保持着。有人用这个方法解决了当Activity被消除后依然保持引用的问题。但是你会发现，如果你需要在WebView中打开链接或者你打开的页面带有flash，获得你的WebView想弹出一个dialog，都会导致从ApplicationContext到ActivityContext的强制类型转换错误，从而导致你应用崩溃。

1. What leads to Memory leak

1.1 InnerClass

1. public class InnerClassActivity extends Activity{
2. private static Leak mLeak;
3. class Leak {
4. int a = 3;
5. private Context mLeakContext;
6. Leak(Context context) {
7. mLeakContext = context;
8. }
9. }
10. @Override
11. protected void onCreate(Bundle savedInstanceState) {
12. super.onCreate(savedInstanceState);
13. setContentView(R.layout.test);
14. mLeak = new Leak(this);
15. Toast.makeText(this, "This is InnerClassActivity", Toast.LENGTH_SHORT).show();
16. }
17. }

1.2 Singleton

1. public class Singleton {
2. private static Singleton instance;
3. private Context mContext1;
4. private Singleton(Context context) {
5. this.mContext1 = context;
6. }
8. public static Singleton getInstance(Context context) {
9. if(instance == null) {
10. synchronized (Singleton.class) {
11. if (instance == null) {
12. instance = new Singleton(context);
13. }
14. }
15. }
16. return instance;
17. }
18. }

1.3 webview - earlier version

1. public class WebViewCreateActivity extends Activity{
2. @Override
3. protected void onCreate(Bundle savedInstanceState) {
4. super.onCreate(savedInstanceState);
6. setContentView(R.layout.webview_create);
7. LinearLayout ll = (LinearLayout) findViewById(R.id.ll);
8. LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
9. WebView webView = new WebView(this);
10. webView.setLayoutParams(layoutParams);
11. WebSettings webSettings = webView.getSettings();
12. webSettings.setJavaScriptEnabled(true);
13. webSettings.setDomStorageEnabled(true);
14. webView.loadUrl("https://www.baidu.com/");
15. ll.addView(webView);
16. Toast.makeText(this, "Hello", Toast.LENGTH_SHORT).show();
17. }
18. }

2. How to detect the Memory Leak

2.1 Android Studio

• GC manually
• dump Java Heap

2.2 MemoryLeak in Our Project

品牌	固件	泄漏点
三星	4.0.4	LightAppManager
小米	5.0.1	LightAppManager/ mAccessibilityManager
华为	6.0	LightAppManager/ mAccessibilityManager

2.2.1 LightAppManager泄漏

3次手动GC后，内存的增长：

泄漏点1： LightAppManager 泄漏

泄漏点2： WebView-wrapper getSystemService泄漏

3. 官方态度

It's 2016 now and, as far as I can see it, the issue still hasn't been resolved. I tested it on Nexus 5 and Nexus 6 with the latest WebView updates (since the component is now separate from the OS itself). Could someone, please, take a look at this issue?!

来源： https://code.google.com/p/android/issues/detail?id=9375

转载于:https://www.cnblogs.com/linkun/p/6254479.html