Android 泄漏检测
每次我试图显示DialogFragment时，都会出现内存泄漏 这就是我的测试对话框（取自android开发者页面）的样子：Android 泄漏检测,android,android-dialogfragment,leakcanary,Android,Android Dialogfragment,Leakcanary,每次我试图显示DialogFragment时，都会出现内存泄漏 这就是我的测试对话框（取自android开发者页面）的样子： public class TestDialog extends DialogFragment { public static TestDialog newInstance(int title) { TestDialog frag = new TestDialog(); Bundle args = new Bundle();
public class TestDialog extends DialogFragment {
public static TestDialog newInstance(int title) {
TestDialog frag = new TestDialog();
Bundle args = new Bundle();
args.putInt("title", title);
frag.setArguments(args);
return frag;
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
int title = getArguments().getInt("title");
return new AlertDialog.Builder(getActivity())
.setIcon(R.drawable.ic_action_about)
.setTitle(title)
.setPositiveButton(R.string.ok,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
//((FragmentAlertDialog)getActivity()).doPositiveClick();
}
}
)
.setNegativeButton(R.string.cancel,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
//((FragmentAlertDialog)getActivity()).doNegativeClick();
}
}
)
.create();
}
}
DialogFragment newFragment = TestDialog.newInstance(R.string.company_title);
newFragment.show(getFragmentManager(), "dialog");
如何解决此泄漏（或者至少隐藏它，因为canaryleak对所有这些通知越来越讨厌）？此泄漏导致的原因是
DialogFragment的源代码：
@Override
public void onActivityCreated(Bundle savedInstanceState) {
...
// other codes
...
mDialog.setCancelable(mCancelable);
// hear is the main reason
mDialog.setOnCancelListener(this);
mDialog.setOnDismissListener(this);
...
// other codes
...
}
让我们看看函数Dialog.SetOnCancelListener（DialogInterface.OnCancelListener）
中发生了什么：
最后，将调用函数Message.get（Handler、int、Object）
：
/**
* Same as {@link #obtain()}, but sets the values of the <em>target</em>, <em>what</em>, and <em>obj</em>
* members.
* @param h The <em>target</em> value to set.
* @param what The <em>what</em> value to set.
* @param obj The <em>object</em> method to set.
* @return A Message object from the global pool.
*/
public static Message obtain(Handler h, int what, Object obj) {
Message m = obtain();
m.target = h;
m.what = what;
m.obj = obj;
return m;
}
/**
*与{@link#get（）}相同，但设置目标、what和obj的值
*成员们。
*@param h要设置的目标值。
*@param要设置的值是多少。
*@param obj要设置的对象方法。
*@从全局池返回消息对象。
*/
获取公共静态消息（处理程序h、int-what、对象obj）{
消息m=获取（）；
m、 目标=h；
m、 什么=什么；
m、 obj=obj；
返回m；
}
我们可以看到，cancelMessage
保存了DialogFragment
的实例，这导致了内存泄漏。我只想让你知道这一点，除了不要使用DialogFragment
，我没有办法避免它。或者有更好的解决方案的人请告诉我。如果有人仍然遇到这个问题：我通过将leakcanary更新到最新版本（目前为2.4）来解决这个问题。好像是假阳性检测。我使用的是leakcanary 2.0beta-3。基于@EmMper的答案。如果您不需要onCancelListener，这里有一个解决方案
import android.app.Activity
import android.os.Bundle
import androidx.annotation.MainThread
import androidx.fragment.app.DialogFragment
open class PatchedDialogFragment : DialogFragment() {
@MainThread
override fun onActivityCreated(savedInstanceState: Bundle?) {
// Fixing the issue described here
// https://stackoverflow.com/questions/53185154/leakcanary-dialogfragment-leak-detection
val initialShowsDialog = showsDialog
showsDialog = false
super.onActivityCreated(savedInstanceState)
showsDialog = initialShowsDialog
if (!showsDialog) {
return
}
val view = view
if (view != null) {
check(view.parent == null) { "DialogFragment can not be attached to a container view" }
dialog!!.setContentView(view)
}
val activity: Activity? = activity
if (activity != null) {
dialog!!.ownerActivity = activity
}
dialog!!.setCancelable(isCancelable)
if (savedInstanceState != null) {
val dialogState =
savedInstanceState.getBundle("android:savedDialogState")
if (dialogState != null) {
dialog!!.onRestoreInstanceState(dialogState)
}
}
}
}
只需扩展PatchedDialogFragment而不是DialogFragment。我通过从自定义的DialogFragment
实现中删除OnDismissListener
和OnCancelListener
来消除此漏洞。
我还必须将null传递给负按钮侦听器：.setNegativeButton（R.string.cancel，null）
代码是否驻留在您发布的可运行文件中？如果是这样的话，我想你可以忽略这一点。我不确定我是否明白。这只是一个普通的setOnClickListener按钮。
/**
* Same as {@link #obtain()}, but sets the values of the <em>target</em>, <em>what</em>, and <em>obj</em>
* members.
* @param h The <em>target</em> value to set.
* @param what The <em>what</em> value to set.
* @param obj The <em>object</em> method to set.
* @return A Message object from the global pool.
*/
public static Message obtain(Handler h, int what, Object obj) {
Message m = obtain();
m.target = h;
m.what = what;
m.obj = obj;
return m;
}
import android.app.Activity
import android.os.Bundle
import androidx.annotation.MainThread
import androidx.fragment.app.DialogFragment
open class PatchedDialogFragment : DialogFragment() {
@MainThread
override fun onActivityCreated(savedInstanceState: Bundle?) {
// Fixing the issue described here
// https://stackoverflow.com/questions/53185154/leakcanary-dialogfragment-leak-detection
val initialShowsDialog = showsDialog
showsDialog = false
super.onActivityCreated(savedInstanceState)
showsDialog = initialShowsDialog
if (!showsDialog) {
return
}
val view = view
if (view != null) {
check(view.parent == null) { "DialogFragment can not be attached to a container view" }
dialog!!.setContentView(view)
}
val activity: Activity? = activity
if (activity != null) {
dialog!!.ownerActivity = activity
}
dialog!!.setCancelable(isCancelable)
if (savedInstanceState != null) {
val dialogState =
savedInstanceState.getBundle("android:savedDialogState")
if (dialogState != null) {
dialog!!.onRestoreInstanceState(dialogState)
}
}
}
}