android4.2源码目录结构 android dialog源码

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墨香四溢 2023-07-07 17:19:08

文章标签 android dialog构造函数构造函数 ci ico 文章分类 代码人生

文章目录AlertDialog使用

AlertDialog源码解析

总结在Activity中展示AlertDialognew AlertDialog.Builder(this) .setTitle("标题") .setMessage("内容") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }) .create() .show();

效果:

android4.2源码目录结构 android dialog源码_ico

android4.2源码目录结构 android dialog源码_ci_02

android4.2源码目录结构 android dialog源码_android dialog构造函数_03

AlertDialog源码解析:查看AlertDialog的继承(使用V7包中的)

android4.2源码目录结构 android dialog源码_ico_04

android4.2源码目录结构 android dialog源码_ico_05

查看AlertDialog的构造函数

1.发现AlertDialog的构造函数都是protected修饰的,所以可以知道在外部不能直接new出对象,需要使用静态内部类Builder,接下来会详细介绍

2.第一和第三个构造函数都会调用第二个构造函数,在第二个构造函数中主要处理了

protected AlertDialog(@NonNull Context context) {
this(context, 0);
}
/**
* Construct an AlertDialog that uses an explicit theme.  The actual style
* that an AlertDialog uses is a private implementation, however you can
* here supply either the name of an attribute in the theme from which
* to get the dialog's style (such as {@link R.attr#alertDialogTheme}.
*/
protected AlertDialog(@NonNull Context context, @StyleRes int themeResId) {
super(context, resolveDialogTheme(context, themeResId));
mAlert = new AlertController(getContext(), this, getWindow());
}
protected AlertDialog(@NonNull Context context, boolean cancelable,
@Nullable OnCancelListener cancelListener) {
this(context, 0);
setCancelable(cancelable);
setOnCancelListener(cancelListener);
}

a.调用方法resolveDialogThrem(),确定Dialog主题,如果调用者没有设置自己的主题,就使用系统默认主题

b.实例化全局变量mAlert = new AlertController();该变量主要用来数据

static int resolveDialogTheme(@NonNull Context context, @StyleRes int resid) {
if (resid >= 0x01000000) {   // start of real resource IDs.
return resid;
} else {
TypedValue outValue = new TypedValue();
context.getTheme().resolveAttribute(R.attr.alertDialogTheme, outValue, true);
return outValue.resourceId;
}
}

接着我们再看下AlertDialog的父类Dialog的构造函数做了那些操作我们方法在Dialog也是做了初始化的操作,其中最重要的是处理化了Window对象

public Dialog(@NonNull Context context) {
this(context, 0, true);
}
public Dialog(@NonNull Context context, @StyleRes int themeResId) {
this(context, themeResId, true);
}
Dialog(@NonNull Context context, @StyleRes int themeResId, boolean createContextThemeWrapper) {
if (createContextThemeWrapper) {
if (themeResId == 0) {
final TypedValue outValue = new TypedValue();
context.getTheme().resolveAttribute(R.attr.dialogTheme, outValue, true);
themeResId = outValue.resourceId;
}
mContext = new ContextThemeWrapper(context, themeResId);
} else {
mContext = context;
}
//通过上下文拿到窗体管理器WindowManager
mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
//初始化Window,使用的是其子类PhoneWindow
final Window w = new PhoneWindow(mContext);
mWindow = w;
w.setCallback(this);
w.setOnWindowDismissedCallback(this);
w.setWindowManager(mWindowManager, null, null);
w.setGravity(Gravity.CENTER);
//初始化Handler
mListenersHandler = new ListenersHandler(this);
}
Builder源码解析Builder是AlertDialog中的一个静态内部类->查看构造函数public static class Builder {
private final AlertController.AlertParams P;
private final int mTheme;
public Builder(@NonNull Context context) {
this(context, resolveDialogTheme(context, 0));
}
public Builder(@NonNull Context context, @StyleRes int themeResId) {
P = new AlertController.AlertParams(new ContextThemeWrapper(
context, resolveDialogTheme(context, themeResId)));
mTheme = themeResId;
}
}

1.构造函数中主要初始化变量P = new AlertController.AlertParams(),该变量也是用来保存封装数据用的接下来就是很多设置方法,并且这些设置的数据都是放在变量P中./**

* 设置title,数据保存在P中的mTitle属性中
*/
public Builder setTitle(@StringRes int titleId) {
P.mTitle = P.mContext.getText(titleId);
return this;
}
public Builder setTitle(@Nullable CharSequence title) {
P.mTitle = title;
return this;
}
/**
* 设置自己想要的title布局样式
*/
public Builder setCustomTitle(@Nullable View customTitleView) {
P.mCustomTitleView = customTitleView;
return this;
}
/**
* 设置展示内容
*/
public Builder setMessage(@StringRes int messageId) {
P.mMessage = P.mContext.getText(messageId);
return this;
}
public Builder setMessage(@Nullable CharSequence message) {
P.mMessage = message;
return this;
}
/**
* 设置title位置的icon
*/
public Builder setIcon(@DrawableRes int iconId) {
P.mIconId = iconId;
return this;
}
public Builder setIcon(@Nullable Drawable icon) {
P.mIcon = icon;
return this;
}
/**
* 分别设置按钮文字和点击事件
*/
public Builder setPositiveButton(CharSequence text, final OnClickListener listener) {
P.mPositiveButtonText = text;
P.mPositiveButtonListener = listener;
return this;
}
public Builder setNegativeButton(CharSequence text, final OnClickListener listener) {
P.mNegativeButtonText = text;
P.mNegativeButtonListener = listener;
return this;
}
public Builder setNeutralButton(CharSequence text, final OnClickListener listener) {
P.mNeutralButtonText = text;
P.mNeutralButtonListener = listener;
return this;
}
/**
* 设置Dialog是否可以在外部点击消失,默认为true,在外部点击消失会回调接口OnCancelListener
*/
public Builder setCancelable(boolean cancelable) {
P.mCancelable = cancelable;
return this;
}
/**
* 在外部点击消失会回调接口OnCancelListener
*/
public Builder setOnCancelListener(OnCancelListener onCancelListener) {
P.mOnCancelListener = onCancelListener;
return this;
}
/**
* Dialog消失时调用dismiss()方法,进行回调
*/
public Builder setOnDismissListener(OnDismissListener onDismissListener) {
P.mOnDismissListener = onDismissListener;
return this;
}
/**
* 按键点击事件监听,有返回boolean值,默认为false,表示dialog可以消失,如果返回true按返回键dialog不会消失,有特殊请求的可以在该回调方法中处理
*/
public Builder setOnKeyListener(OnKeyListener onKeyListener) {
P.mOnKeyListener = onKeyListener;
return this;
}
=============================================================================
.setOnKeyListener(new DialogInterface.OnKeyListener() {
@Override
public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
Logger.d("setOnKeyListener keyCode:"+keyCode);
return false;
}
})
=============================================================================/**
* 设置展示单选列表
*/
public Builder setItems(CharSequence[] items, final OnClickListener listener) {
P.mItems = items;
P.mOnClickListener = listener;
return this;
}
/**
* 也是单选,和上一种有区别
*/
public Builder setSingleChoiceItems(CharSequence[] items, int checkedItem, final OnClickListener listener) {
P.mItems = items;
P.mOnClickListener = listener;
P.mCheckedItem = checkedItem;
P.mIsSingleChoice = true;
return this;
}
/**
* 直接设置一个设配器,Dialog会展示一个listView
*/
public Builder setAdapter(final ListAdapter adapter, final OnClickListener listener) {
P.mAdapter = adapter;
P.mOnClickListener = listener;
return this;
}
/**
* 直接传入一个游标
*/
public Builder setCursor(final Cursor cursor, final OnClickListener listener,
String labelColumn) {
P.mCursor = cursor;
P.mLabelColumn = labelColumn;
P.mOnClickListener = listener;
return this;
}
/**
* 设置多选数据,和已选项
*/
public Builder setMultiChoiceItems(CharSequence[] items, boolean[] checkedItems,
final OnMultiChoiceClickListener listener) {
P.mItems = items;
P.mOnCheckboxClickListener = listener;
P.mCheckedItems = checkedItems;
P.mIsMultiChoice = true;
return this;
}
上面的这些方法都是一些属性的设置,每个方法都有注释,方便查看,那将Dialog实例化,并展示出来是怎样的呢,我们接着往下看/**
* Dialog内容部分展示自己的布局界面
*/
public Builder setView(View view) {
P.mView = view;
P.mViewLayoutResId = 0;
P.mViewSpacingSpecified = false;
return this;
}
实例化AlertDialog--create()方法public AlertDialog create() {
// 实例化
final AlertDialog dialog = new AlertDialog(P.mContext, mTheme);
//将Builder中变量P的数据,设置到AlertDialog的变量mAlert
P.apply(dialog.mAlert);
//还是设置
dialog.setCancelable(P.mCancelable);
if (P.mCancelable) {
dialog.setCanceledOnTouchOutside(true);
}
dialog.setOnCancelListener(P.mOnCancelListener);
dialog.setOnDismissListener(P.mOnDismissListener);
if (P.mOnKeyListener != null) {
dialog.setOnKeyListener(P.mOnKeyListener);
}
return dialog;
}
我们看下P.apply()方法的实现:==>就是将P中保存的数据设置给AlertDialog的变量AlertController mAlert;public void apply(AlertController dialog) {
if (mCustomTitleView != null) {
dialog.setCustomTitle(mCustomTitleView);
} else {
if (mTitle != null) {
dialog.setTitle(mTitle);
}
if (mIcon != null) {
dialog.setIcon(mIcon);
}
if (mIconId != 0) {
dialog.setIcon(mIconId);
}
if (mIconAttrId != 0) {
dialog.setIcon(dialog.getIconAttributeResId(mIconAttrId));
}
}
if (mMessage != null) {
dialog.setMessage(mMessage);
}
if (mPositiveButtonText != null) {
dialog.setButton(DialogInterface.BUTTON_POSITIVE, mPositiveButtonText,
mPositiveButtonListener, null);
}
if (mNegativeButtonText != null) {
dialog.setButton(DialogInterface.BUTTON_NEGATIVE, mNegativeButtonText,
mNegativeButtonListener, null);
}
if (mNeutralButtonText != null) {
dialog.setButton(DialogInterface.BUTTON_NEUTRAL, mNeutralButtonText,
mNeutralButtonListener, null);
}
//如果设置了mItems数据,表示是单选或者多选列表,则创建一个ListView
if ((mItems != null) || (mCursor != null) || (mAdapter != null)) {
createListView(dialog);
}
//将mView设置给Dialog
if (mView != null) {
if (mViewSpacingSpecified) {
dialog.setView(mView, mViewSpacingLeft, mViewSpacingTop, mViewSpacingRight,
mViewSpacingBottom);
} else {
dialog.setView(mView);
}
} else if (mViewLayoutResId != 0) {
dialog.setView(mViewLayoutResId);
}
/*
dialog.setCancelable(mCancelable);
dialog.setOnCancelListener(mOnCancelListener);
if (mOnKeyListener != null) {
dialog.setOnKeyListener(mOnKeyListener);
}
*/
}

android4.2源码目录结构 android dialog源码_构造函数_06

android4.2源码目录结构 android dialog源码_ico_07

从上图中可以发现,AlertParams是AlertController的内部类,且他们都有相同的属性.这里使用的就是Builder设计模式的变种实现方式再接着看AlertController的构造函数做了什么处理

public AlertController(Context context, AppCompatDialog di, Window window) {
//赋值
mContext = context;
mDialog = di;
mWindow = window;
mHandler = new ButtonHandler(di);
final TypedArray a = context.obtainStyledAttributes(null, R.styleable.AlertDialog,
R.attr.alertDialogStyle, 0);
//获取属性信息
mAlertDialogLayout = a.getResourceId(R.styleable.AlertDialog_android_layout, 0);
mButtonPanelSideLayout = a.getResourceId(R.styleable.AlertDialog_buttonPanelSideLayout, 0);
mListLayout = a.getResourceId(R.styleable.AlertDialog_listLayout, 0);
mMultiChoiceItemLayout = a.getResourceId(R.styleable.AlertDialog_multiChoiceItemLayout, 0);
mSingleChoiceItemLayout = a
.getResourceId(R.styleable.AlertDialog_singleChoiceItemLayout, 0);
mListItemLayout = a.getResourceId(R.styleable.AlertDialog_listItemLayout, 0);
mShowTitle = a.getBoolean(R.styleable.AlertDialog_showTitle, true);
a.recycle();
/**
* 我们使用自定义的Title,所以Dialog不需要设置Window title
*/
di.supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
}
数据都准备好了,dialog也实例化了,最后来看Dialog是如何展示的,这里就是用到了Dialog.show()方法===>最最核心方法public void show() {
//Dialog正在展示的逻辑处理,直接return
if (mShowing) {
if (mDecor != null) {
if (mWindow.hasFeature(Window.FEATURE_ACTION_BAR)) {
mWindow.invalidatePanelMenu(Window.FEATURE_ACTION_BAR);
}
mDecor.setVisibility(View.VISIBLE);
}
return;
}
mCanceled = false;
//1.调用Dialog的onCreate()方法
if (!mCreated) {
dispatchOnCreate(null);
} else {
// Fill the DecorView in on any configuration changes that
// may have occured while it was removed from the WindowManager.
final Configuration config = mContext.getResources().getConfiguration();
mWindow.getDecorView().dispatchConfigurationChanged(config);
}
//2.熟悉的onStart()方法
onStart();
//3.拿到Window的DecorView,该mWindow是在Dialog的构造函数中初始化得到
mDecor = mWindow.getDecorView();
if (mActionBar == null && mWindow.hasFeature(Window.FEATURE_ACTION_BAR)) {
final ApplicationInfo info = mContext.getApplicationInfo();
mWindow.setDefaultIcon(info.icon);
mWindow.setDefaultLogo(info.logo);
mActionBar = new WindowDecorActionBar(this);
}
//4.拿到窗体属性
WindowManager.LayoutParams l = mWindow.getAttributes();
if ((l.softInputMode
& WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION) == 0) {
WindowManager.LayoutParams nl = new WindowManager.LayoutParams();
nl.copyFrom(l);
nl.softInputMode |=
WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION;
l = nl;
}
//5.将mDecor添加到WindowManager中
mWindowManager.addView(mDecor, l);
mShowing = true;
//6.发送消息,展示
sendShowMessage();
}

show()方法主要有6个核心方法:通过dispatchOnCreate()方法来调用AlertDialog的onCreate()方法.(Dialog的onCreate()方法是一个空实现)

我们发现在AlertDialog的onCreate()方法中调用了mAlert的installContent()方法,根据方法名称,我们可以猜测这个方法的作用是内容视图的处理,我们往里面查看@Override

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mAlert.installContent();
}AlertController.installContent():public void installContent() {
final int contentView = selectContentView();
mDialog.setContentView(contentView);
setupView();
}
在installContent()方法中又调用了三个方法,这三个方法是核心方法,
a.调用selectContentView()方法,获取Dialog的contentView,就是AlertDialogLayout的布局private int selectContentView() {
if (mButtonPanelSideLayout == 0) {
return mAlertDialogLayout;
}
if (mButtonPanelLayoutHint == AlertDialog.LAYOUT_HINT_SIDE) {
return mButtonPanelSideLayout;
}
return mAlertDialogLayout;
}
b.dialog.setContentView();将上个方法获取的布局,设置给dialog,其实就是调用了Window的setContentView()方法,这一块和Activity的setContentView()方法的逻辑一样public void setContentView(@LayoutRes int layoutResID) {
mWindow.setContentView(layoutResID);
}
c.最后调用了setupView()方法,就是布局控件的一些展示处理首先我们看下AlertDialog的默认xml布局文件<?xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/parentPanel"  //xml文件的根view
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingTop="9dip"
android:paddingBottom="3dip"
android:paddingStart="3dip"
android:paddingEnd="1dip">
//Dialog的顶部控件包括(icon和title)
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="54dip"
android:orientation="vertical">
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center_vertical"
android:layout_marginTop="6dip"
android:layout_marginBottom="9dip"
android:layout_marginStart="10dip"
android:layout_marginEnd="10dip">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:paddingTop="6dip"
android:paddingEnd="10dip"
android:id="@+id/alertTitle"
style="?android:attr/textAppearanceLarge"
android:singleLine="true"
android:ellipsize="end"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAlignment="viewStart" />
//分割线
android:layout_width="match_parent"
android:layout_height="1dip"
android:visibility="gone"
android:scaleType="fitXY"
android:gravity="fill_horizontal"
android:class="lazyload" src="https://img-blog.csdnimg.cn/2022010621340381080.png" data-original="@android:drawable/divider_horizontal_dark" />
//默认的内容展示控件,内部使用ScrollView嵌套TextView进行文本展示
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="2dip"
android:paddingBottom="12dip"
android:paddingStart="14dip"
android:paddingEnd="10dip"
android:overScrollMode="ifContentScrolls">
style="?android:attr/textAppearanceMedium"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dip" />
//自定义的布局添加到这个FrameLayout控件中
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1">
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="5dip"
android:paddingBottom="5dip" />
//底部的按钮展示控件
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="54dip"
android:orientation="vertical" >
style="?android:attr/buttonBarStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingTop="4dip"
android:paddingStart="2dip"
android:paddingEnd="2dip"
android:measureWithLargestChild="true">
android:layout_weight="0.25"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:visibility="gone" />
android:layout_width="0dip"
android:layout_gravity="start"
android:layout_weight="1"
style="?android:attr/buttonBarButtonStyle"
android:maxLines="2"
android:layout_height="wrap_content" />
android:layout_width="0dip"
android:layout_gravity="center_horizontal"
android:layout_weight="1"
style="?android:attr/buttonBarButtonStyle"
android:maxLines="2"
android:layout_height="wrap_content" />
android:layout_width="0dip"
android:layout_gravity="end"
android:layout_weight="1"
style="?android:attr/buttonBarButtonStyle"
android:maxLines="2"
android:layout_height="wrap_content" />
android:layout_width="0dip"
android:layout_weight="0.25"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:visibility="gone" />
再看下setupView()的处理逻辑private void setupView() {
//拿到根view
final View parentPanel = mWindow.findViewById(R.id.parentPanel);
//默认顶部控件
final View defaultTopPanel = parentPanel.findViewById(R.id.topPanel);
//默认内容控件
final View defaultContentPanel = parentPanel.findViewById(R.id.contentPanel);
//默认按钮控件
final View defaultButtonPanel = parentPanel.findViewById(R.id.buttonPanel);
// 如果有自己设置的布局控件,则调用setupCustomContent()
final ViewGroup customPanel = (ViewGroup) parentPanel.findViewById(R.id.customPanel);
setupCustomContent(customPanel);
final View customTopPanel = customPanel.findViewById(R.id.topPanel);
final View customContentPanel = customPanel.findViewById(R.id.contentPanel);
final View customButtonPanel = customPanel.findViewById(R.id.buttonPanel);
// Resolve the correct panels and remove the defaults, if needed.
final ViewGroup topPanel = resolvePanel(customTopPanel, defaultTopPanel);
final ViewGroup contentPanel = resolvePanel(customContentPanel, defaultContentPanel);
final ViewGroup buttonPanel = resolvePanel(customButtonPanel, defaultButtonPanel);
//内容区域控件数据设置-底部按钮区域-和顶部title区域数据填充
setupContent(contentPanel);
setupButtons(buttonPanel);
setupTitle(topPanel);
//展示标示
final boolean hasCustomPanel = customPanel != null
&& customPanel.getVisibility() != View.GONE;
final boolean hasTopPanel = topPanel != null
&& topPanel.getVisibility() != View.GONE;
final boolean hasButtonPanel = buttonPanel != null
&& buttonPanel.getVisibility() != View.GONE;
// Only display the text spacer if we don't have buttons.
if (!hasButtonPanel) {
if (contentPanel != null) {
final View spacer = contentPanel.findViewById(R.id.textSpacerNoButtons);
if (spacer != null) {
spacer.setVisibility(View.VISIBLE);
}
}
}
if (hasTopPanel) {
// Only clip scrolling content to padding if we have a title.
if (mScrollView != null) {
mScrollView.setClipToPadding(true);
}
// Only show the divider if we have a title.
View divider = null;
if (mMessage != null || mListView != null || hasCustomPanel) {
if (!hasCustomPanel) {
divider = topPanel.findViewById(R.id.titleDividerNoCustom);
}
}
if (divider != null) {
divider.setVisibility(View.VISIBLE);
}
} else {
if (contentPanel != null) {
final View spacer = contentPanel.findViewById(R.id.textSpacerNoTitle);
if (spacer != null) {
spacer.setVisibility(View.VISIBLE);
}
}
}
if (mListView instanceof RecycleListView) {
((RecycleListView) mListView).setHasDecor(hasTopPanel, hasButtonPanel);
}
// Update scroll indicators as needed.
if (!hasCustomPanel) {
final View content = mListView != null ? mListView : mScrollView;
if (content != null) {
final int indicators = (hasTopPanel ? ViewCompat.SCROLL_INDICATOR_TOP : 0)
| (hasButtonPanel ? ViewCompat.SCROLL_INDICATOR_BOTTOM : 0);
setScrollIndicators(contentPanel, content, indicators,
ViewCompat.SCROLL_INDICATOR_TOP | ViewCompat.SCROLL_INDICATOR_BOTTOM);
}
}
final ListView listView = mListView;
if (listView != null && mAdapter != null) {
listView.setAdapter(mAdapter);
final int checkedItem = mCheckedItem;
if (checkedItem > -1) {
listView.setItemChecked(checkedItem, true);
listView.setSelection(checkedItem);
}
}
}设置Dialog自定义布局的处理逻辑setupCustomContent()private void setupCustomContent(ViewGroup customPanel) {
final View customView;
//拿到传入进来的自定义布局
if (mView != null) {
customView = mView;
} else if (mViewLayoutResId != 0) {
//传入的是布局id,使用LayoutInflater.inflate方法拿到填充布局
final LayoutInflater inflater = LayoutInflater.from(mContext);
customView = inflater.inflate(mViewLayoutResId, customPanel, false);
} else {
customView = null;
}
final boolean hasCustomView = customView != null;
if (!hasCustomView || !canTextInput(customView)) {
mWindow.setFlags(WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM,
WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);
}
if (hasCustomView) {
//拿到custom控件,进行addView()添加
final FrameLayout custom = (FrameLayout) mWindow.findViewById(R.id.custom);
custom.addView(customView, new LayoutParams(MATCH_PARENT, MATCH_PARENT));
if (mViewSpacingSpecified) {
custom.setPadding(
mViewSpacingLeft, mViewSpacingTop, mViewSpacingRight, mViewSpacingBottom);
}
if (mListView != null) {
((LinearLayout.LayoutParams) customPanel.getLayoutParams()).weight = 0;
}
} else {
//如果没有传入自定义的布局文件,则隐藏
customPanel.setVisibility(View.GONE);
}
}
内容区域数据填充private void setupContent(ViewGroup contentPanel) {
//内容区域外层ScrollView处理
mScrollView = (NestedScrollView) mWindow.findViewById(R.id.scrollView);
mScrollView.setFocusable(false);
mScrollView.setNestedScrollingEnabled(false);
//文本内容控件TextView
mMessageView = (TextView) contentPanel.findViewById(android.R.id.message);
if (mMessageView == null) {
return;
}
//根据文本mMessage判断TextView是否显示
if (mMessage != null) {
mMessageView.setText(mMessage);
} else {
mMessageView.setVisibility(View.GONE);
mScrollView.removeView(mMessageView);
//文本内容是List,则remove调用TextView,添加ListView控件
if (mListView != null) {
final ViewGroup scrollParent = (ViewGroup) mScrollView.getParent();
final int childIndex = scrollParent.indexOfChild(mScrollView);
scrollParent.removeViewAt(childIndex);
scrollParent.addView(mListView, childIndex,
new LayoutParams(MATCH_PARENT, MATCH_PARENT));
} else {
contentPanel.setVisibility(View.GONE);
}
}
}
底部按钮控件展示出来private void setupButtons(ViewGroup buttonPanel) {
int BIT_BUTTON_POSITIVE = 1;
int BIT_BUTTON_NEGATIVE = 2;
int BIT_BUTTON_NEUTRAL = 4;
int whichButtons = 0;
//拿到button1控件
mButtonPositive = (Button) buttonPanel.findViewById(android.R.id.button1);
mButtonPositive.setOnClickListener(mButtonHandler);
//根据文本信息判断是否展示--其他按钮也是一样的处理逻辑
if (TextUtils.isEmpty(mButtonPositiveText)) {
mButtonPositive.setVisibility(View.GONE);
} else {
mButtonPositive.setText(mButtonPositiveText);
mButtonPositive.setVisibility(View.VISIBLE);
whichButtons = whichButtons | BIT_BUTTON_POSITIVE;
}
mButtonNegative = (Button) buttonPanel.findViewById(android.R.id.button2);
mButtonNegative.setOnClickListener(mButtonHandler);
if (TextUtils.isEmpty(mButtonNegativeText)) {
mButtonNegative.setVisibility(View.GONE);
} else {
mButtonNegative.setText(mButtonNegativeText);
mButtonNegative.setVisibility(View.VISIBLE);
whichButtons = whichButtons | BIT_BUTTON_NEGATIVE;
}
mButtonNeutral = (Button) buttonPanel.findViewById(android.R.id.button3);
mButtonNeutral.setOnClickListener(mButtonHandler);
if (TextUtils.isEmpty(mButtonNeutralText)) {
mButtonNeutral.setVisibility(View.GONE);
} else {
mButtonNeutral.setText(mButtonNeutralText);
mButtonNeutral.setVisibility(View.VISIBLE);
whichButtons = whichButtons | BIT_BUTTON_NEUTRAL;
}
//单个按钮的展示逻辑
if (shouldCenterSingleButton(mContext)) {
/*
* If we only have 1 button it should be centered on the layout and
* expand to fill 50% of the available space.
*/
if (whichButtons == BIT_BUTTON_POSITIVE) {
centerButton(mButtonPositive);
} else if (whichButtons == BIT_BUTTON_NEGATIVE) {
centerButton(mButtonNegative);
} else if (whichButtons == BIT_BUTTON_NEUTRAL) {
centerButton(mButtonNeutral);
}
}
final boolean hasButtons = whichButtons != 0;
if (!hasButtons) {
buttonPanel.setVisibility(View.GONE);
}
}
顶部Tiltle控件处理逻辑private void setupTitle(ViewGroup topPanel) {
if (mCustomTitleView != null) {
// 使用自定义的titleView
LayoutParams lp = new LayoutParams(
LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
topPanel.addView(mCustomTitleView, 0, lp);
// Hide the title template
View titleTemplate = mWindow.findViewById(R.id.title_template);
titleTemplate.setVisibility(View.GONE);
} else {
mIconView = (ImageView) mWindow.findViewById(android.R.id.icon);
final boolean hasTextTitle = !TextUtils.isEmpty(mTitle);
//title控件展示逻辑
if (hasTextTitle && mShowTitle) {
// Display the title if a title is supplied, else hide it.
mTitleView = (TextView) mWindow.findViewById(R.id.alertTitle);
mTitleView.setText(mTitle);
// Do this last so that if the user has supplied any icons we
// use them instead of the default ones. If the user has
// specified 0 then make it disappear.
if (mIconId != 0) {
mIconView.setImageResource(mIconId);
} else if (mIcon != null) {
mIconView.setImageDrawable(mIcon);
} else {
// Apply the padding from the icon to ensure the title is
// aligned correctly.
mTitleView.setPadding(mIconView.getPaddingLeft(),
mIconView.getPaddingTop(),
mIconView.getPaddingRight(),
mIconView.getPaddingBottom());
mIconView.setVisibility(View.GONE);
}
} else {
// Hide the title template
final View titleTemplate = mWindow.findViewById(R.id.title_template);
titleTemplate.setVisibility(View.GONE);
mIconView.setVisibility(View.GONE);
topPanel.setVisibility(View.GONE);
}
}
}处理AlertDialog的控件后,接着调用AlertDialog的onStart()方法
最后将Dialog的DecorView添加到WindowManager中,并且显示出来,到这里Dialog就出现在用户的视野中.Handler接收消息private static final class ListenersHandler extends Handler {
private final WeakReference mDialog;
public ListenersHandler(Dialog dialog) {
//拿到Dialog的实例,软引用
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;
}
}
}

总结:经过前面在AlertDialog源码中的杀入杀出,我们了解了AlertDialog是如何实现的,他主要是使用内部类Builder进行数据设置,接着调用create()方法真正创建AlertDialog,并将之间设置的各种数据apply()到控制器AlertController类中,接着是进行展示,调用show()方法,这快的实现原理和Activity的展示逻辑一样,都使用借用WindowManager来进行处理.

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