一、为什么要使用DialogFragment:
在程序开发中我们经常要做一些弹窗提醒，如果用自带的Dialog虽然能解决一部分，但强大的UI是不会给你这个机会的，各种自定义UI,时间选择器弹窗，巴拉巴拉~~~
使用DialogFragment就是能配合一些工具进行自定义，同时官方也是比较推荐使用，极大方便了开发,比如自定义一个baseDialogFragment.
package com.gzjiequan.rescuewithyou.customwidget;
import android.app.Dialog;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.DialogFragment;
import com.gzjiequan.rescuewithyou.R;
import com.zhy.autolayout.utils.AutoUtils;
import butterknife.ButterKnife;
import butterknife.Unbinder;
/**
* @author Wudi
* @date 2019/4/16
*/
public abstract class BaseDialogFragment extends DialogFragment {
protected String TAG = this.getClass().getSimpleName();
private static final String SAVED_DIALOG_STATE_TAG = "android:savedDialogState";
Unbinder unbinder;
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (getDialog() != null) {
try {
// 解决Dialog内D存泄漏
getDialog().setOnDismissListener(null);
getDialog().setOnCancelListener(null);
} catch (Exception e) {
e.printStackTrace();
}
}
}
@Override
public void onStart() {
super.onStart();
// 全屏显示Dialog，重新测绘宽高
if (getDialog() != null) {
DisplayMetrics dm = new DisplayMetrics();
getActivity().getWindowManager().getDefaultDisplay().getMetrics(dm);
getDialog().getWindow().setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
}
}
@Override
public void onPause() {
super.onPause();
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(getLayoutResId(), container, false);
AutoUtils.auto(rootView);
unbinder = ButterKnife.bind(this, rootView);
initView();
return rootView;
}
/**
* 获取布局文件
*
* @return
*/
protected abstract int getLayoutResId();
/**
* 初始化界面
*/
protected void initView() {
}
@Override
public void onDestroyView() {
super.onDestroyView();
unbinder.unbind();
}
/**
* 全屏显示Dialog
*
* @param savedInstanceState
* @return
*/
@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
Dialog dialog = new Dialog(getActivity());
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.getWindow().setBackgroundDrawableResource(R.color.transparent);
dialog.setCanceledOnTouchOutside(false);
dialog.setCancelable(false);
return dialog;
}
}
二、内存泄漏的原因：
QQ图片20190610162758.jpg
源码如下：
Dialog(@NonNull Context context, @StyleRes int themeResId, boolean createContextThemeWrapper) {
if (createContextThemeWrapper) {
if (themeResId == ResourceId.ID_NULL) {
final TypedValue outValue = new TypedValue();
context.getTheme().resolveAttribute(R.attr.dialogTheme, outValue, true);
themeResId = outValue.resourceId;
}
mContext = new ContextThemeWrapper(context, themeResId);
} else {
mContext = context;
}
mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
final Window w = new PhoneWindow(mContext);
mWindow = w;
w.setCallback(this);
w.setOnWindowDismissedCallback(this);
w.setOnWindowSwipeDismissedCallback(() -> {
if (mCancelable) {
cancel();
}
});
w.setWindowManager(mWindowManager, null, null);
w.setGravity(Gravity.CENTER);
mListenersHandler = new ListenersHandler(this);
}
private static final class ListenersHandler extends Handler {
private final WeakReference<DialogInterface> mDialog;
public ListenersHandler(Dialog dialog) {
mDialog = new WeakReference<>(dialog);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case DISMISS:
((OnDismissListener) msg.obj).onDismiss(mDialog.get());
break;
case CANCEL:
((OnCancelListener) msg.obj).onCancel(mDialog.get());
break;
case SHOW:
((OnShowListener) msg.obj).onShow(mDialog.get());
break;
}
}
}
/**
* Set a listener to be invoked when the dialog is canceled.
*
* <p>This will only be invoked when the dialog is canceled.
* Cancel events alone will not capture all ways that
* the dialog might be dismissed. If the creator needs
* to know when a dialog is dismissed in general, use
* {@link #setOnDismissListener}.</p>
*
* @param listener The {@link DialogInterface.OnCancelListener} to use.
*/
public void setOnCancelListener(@Nullable OnCancelListener listener) {
if (mCancelAndDismissTaken != null) {
throw new IllegalStateException(
"OnCancelListener is already taken by "
+ mCancelAndDismissTaken + " and can not be replaced.");
}
if (listener != null) {
mCancelMessage = mListenersHandler.obtainMessage(CANCEL, listener);
} else {
mCancelMessage = null;
}
}
/**
* Set a message to be sent when the dialog is canceled.
* @param msg The msg to send when the dialog is canceled.
* @see #setOnCancelListener(android.content.DialogInterface.OnCancelListener)
*/
public void setCancelMessage(@Nullable Message msg) {
mCancelMessage = msg;
}
/**
* Set a listener to be invoked when the dialog is dismissed.
* @param listener The {@link DialogInterface.OnDismissListener} to use.
*/
public void setOnDismissListener(@Nullable OnDismissListener listener) {
if (mCancelAndDismissTaken != null) {
throw new IllegalStateException(
"OnDismissListener is already taken by "
+ mCancelAndDismissTaken + " and can not be replaced.");
}
if (listener != null) {
mDismissMessage = mListenersHandler.obtainMessage(DISMISS, listener);
} else {
mDismissMessage = null;
}
}
但一般在DialogFragment的源码默认实现了对dialog的取消和结束的监听：
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// 通过设置为false 将进行reture,后面将不再执行监听注册
if (!mShowsDialog) {
return;
}
View view = getView();
if (view != null) {
if (view.getParent() != null) {
throw new IllegalStateException(
"DialogFragment can not be attached to a container view");
}
mDialog.setContentView(view);
}
final Activity activity = getActivity();
if (activity != null) {
mDialog.setOwnerActivity(activity);
}
mDialog.setCancelable(mCancelable);
mDialog.setOnCancelListener(this);
mDialog.setOnDismissListener(this);
if (savedInstanceState != null) {
Bundle dialogState = savedInstanceState.getBundle(SAVED_DIALOG_STATE_TAG);
if (dialogState != null) {
mDialog.onRestoreInstanceState(dialogState);
}
}
}
根据源码分析，DialogFragment的dialog的变量Handler对DialogFragment持有。
网上有些分析是直接置为空，但是根本不能解决问题，在super.onActivityCreated(savedInstanceState)中仍然会handler先持有DialogFragment。
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (getDialog() != null) {
try {
// 解决Dialog内存存泄漏
getDialog().setOnDismissListener(null);
getDialog().setOnCancelListener(null);
} catch (Exception e) {
e.printStackTrace();
}
}
}
最终解决方案，重写onActivityCreated方法，并在super.onActivityCreated(savedInstanceState),修改dialog显示.
private static final String SAVED_DIALOG_STATE_TAG = "android:savedDialogState";
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
if (getShowsDialog()) {
setShowsDialog(false);
}
super.onActivityCreated(savedInstanceState);
setShowsDialog(true);
View view = getView();
if (view != null) {
if (view.getParent() != null) {
throw new IllegalStateException(
"DialogFragment can not be attached to a container view");
}
getDialog().setContentView(view);
}
final Activity activity = getActivity();
if (activity != null) {
getDialog().setOwnerActivity(activity);
}
if (savedInstanceState != null) {
Bundle dialogState = savedInstanceState.getBundle(SAVED_DIALOG_STATE_TAG);
if (dialogState != null) {
getDialog().onRestoreInstanceState(dialogState);
}
}
}
