android源码浅析--AlertController
16lz
2021-12-04
在android源码解析--AlertDialog及AlertDialog.Builder这篇文章中，讲到在Builder中功能的实现主要是调用AlertController实现的，而该类是android内部类，在package com.android.internal.app包中，不能在Eclipse中通过ctrl键来跟踪源码，所以使用Source Insight软件打开该软件源码，查看一下。
跟以前一样，先看下AlertController类中的私有成员变量：
private final Context mContext; private final DialogInterface mDialogInterface; private final Window mWindow; private CharSequence mTitle; private CharSequence mMessage; private ListView mListView; private View mView; private int mViewSpacingLeft; private int mViewSpacingTop; private int mViewSpacingRight; private int mViewSpacingBottom; private boolean mViewSpacingSpecified = false; private Button mButtonPositive; private CharSequence mButtonPositiveText; private Message mButtonPositiveMessage; private Button mButtonNegative; private CharSequence mButtonNegativeText; private Message mButtonNegativeMessage; private Button mButtonNeutral; private CharSequence mButtonNeutralText; private Message mButtonNeutralMessage; private ScrollView mScrollView; private int mIconId = -1; private Drawable mIcon; private ImageView mIconView; private TextView mTitleView; private TextView mMessageView; private View mCustomTitleView; private boolean mForceInverseBackground; private ListAdapter mAdapter; private int mCheckedItem = -1; private int mAlertDialogLayout; private int mListLayout; private int mMultiChoiceItemLayout; private int mSingleChoiceItemLayout; private int mListItemLayout; private Handler mHandler;
mAlertDialogLayout：AlertDialog布局
mListLayout：List布局
mMultiChoiceItemLayout：多选布局
mSingleChoiceItemLayout：单选布局
mListItemLayout：listItem布局
接着下面是一个自定义的View OnClickListener事件，其目的把点击对象的信息发送到对应的线程（UI线程）：
View.OnClickListener mButtonHandler = new View.OnClickListener() { public void onClick(View v) { Message m = null; if (v == mButtonPositive && mButtonPositiveMessage != null) { m = Message.obtain(mButtonPositiveMessage); } else if (v == mButtonNegative && mButtonNegativeMessage != null) { m = Message.obtain(mButtonNegativeMessage); } else if (v == mButtonNeutral && mButtonNeutralMessage != null) { m = Message.obtain(mButtonNeutralMessage); } if (m != null) { m.sendToTarget(); } // Post a message so we dismiss after the above handlers are executed mHandler.obtainMessage(ButtonHandler.MSG_DISMISS_DIALOG, mDialogInterface) .sendToTarget(); } }; 前面获取点击传递的Message，发送到目标线程（UI线程），然后再发送一个Message，通知UI线程关闭此对话框。里面使用到的ButtonHandler.MSG_DISMISS_DIALOG，就在下面代码中定义（关于Message和Handler发送消息，请参看前面博文）。
private static final class ButtonHandler extends Handler { // Button clicks have Message.what as the BUTTON{1,2,3} constant private static final int MSG_DISMISS_DIALOG = 1; private WeakReference<DialogInterface> mDialog; public ButtonHandler(DialogInterface dialog) { mDialog = new WeakReference<DialogInterface>(dialog); } @Override public void handleMessage(Message msg) { switch (msg.what) { case DialogInterface.BUTTON_POSITIVE: case DialogInterface.BUTTON_NEGATIVE: case DialogInterface.BUTTON_NEUTRAL: ((DialogInterface.OnClickListener) msg.obj).onClick(mDialog.get(), msg.what); break; case MSG_DISMISS_DIALOG: ((DialogInterface) msg.obj).dismiss(); } } } 看一下逻辑的处理，如果传进来的Message的信息是DialogInterface.BUTTON_POSITIVE、DialogInterface.BUTTON_NEGATIVE、DialogInterface.BUTTON_NEUTRAL响应其DialogInterface.OnClickListener中的OnClick事件。如果是MSG_DISMISS_DIALOG，就关闭其对话框窗口。
下面是一个判断对话框单个Button是否应居中：
private static boolean shouldCenterSingleButton(Context context) { TypedValue outValue = new TypedValue(); context.getTheme().resolveAttribute(com.android.internal.R.attr.alertDialogCenterButtons, outValue, true); return outValue.data != 0; } 再往下是其构造函数：
public AlertController(Context context, DialogInterface di, Window window) { mContext = context; mDialogInterface = di; mWindow = window; mHandler = new ButtonHandler(di); TypedArray a = context.obtainStyledAttributes(null, com.android.internal.R.styleable.AlertDialog, com.android.internal.R.attr.alertDialogStyle, 0); mAlertDialogLayout = a.getResourceId(com.android.internal.R.styleable.AlertDialog_layout, com.android.internal.R.layout.alert_dialog); mListLayout = a.getResourceId( com.android.internal.R.styleable.AlertDialog_listLayout, com.android.internal.R.layout.select_dialog); mMultiChoiceItemLayout = a.getResourceId( com.android.internal.R.styleable.AlertDialog_multiChoiceItemLayout, com.android.internal.R.layout.select_dialog_multichoice); mSingleChoiceItemLayout = a.getResourceId( com.android.internal.R.styleable.AlertDialog_singleChoiceItemLayout, com.android.internal.R.layout.select_dialog_singlechoice); mListItemLayout = a.getResourceId( com.android.internal.R.styleable.AlertDialog_listItemLayout, com.android.internal.R.layout.select_dialog_item); a.recycle(); } 初始化上面提到的私有变量（关于TypeArray的用法，参考：http://blog.csdn.net/aomandeshangxiao/article/details/7449973）。
下面的静态方法是判断View是否支持输入：
static boolean canTextInput(View v) { if (v.onCheckIsTextEditor()) { return true; } if (!(v instanceof ViewGroup)) { return false; } ViewGroup vg = (ViewGroup)v; int i = vg.getChildCount(); while (i > 0) { i--; v = vg.getChildAt(i); if (canTextInput(v)) { return true; } } return false; } 是文本编辑控件就返回true，然后弹出软键盘。
下面方法，插入内容：
public void installContent() { /* We use a custom title so never request a window title */ //无标题模式 mWindow.requestFeature(Window.FEATURE_NO_TITLE); //如果视图为空，或者不是可编辑控件，那么就自动隐藏掉软键盘 if (mView == null || !canTextInput(mView)) { mWindow.setFlags(WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM, WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM); } //设置系统AlertDialog为视图 mWindow.setContentView(mAlertDialogLayout); setupView(); } 看一下其调用的setupView方法（384行）：
private void setupView() { LinearLayout contentPanel = (LinearLayout) mWindow.findViewById(R.id.contentPanel); setupContent(contentPanel); boolean hasButtons = setupButtons(); LinearLayout topPanel = (LinearLayout) mWindow.findViewById(R.id.topPanel); TypedArray a = mContext.obtainStyledAttributes( null, com.android.internal.R.styleable.AlertDialog, com.android.internal.R.attr.alertDialogStyle, 0); boolean hasTitle = setupTitle(topPanel); View buttonPanel = mWindow.findViewById(R.id.buttonPanel); if (!hasButtons) { buttonPanel.setVisibility(View.GONE); mWindow.setCloseOnTouchOutsideIfNotSet(true); } FrameLayout customPanel = null; if (mView != null) { customPanel = (FrameLayout) mWindow.findViewById(R.id.customPanel); FrameLayout custom = (FrameLayout) mWindow.findViewById(R.id.custom); custom.addView(mView, new LayoutParams(MATCH_PARENT, MATCH_PARENT)); if (mViewSpacingSpecified) { custom.setPadding(mViewSpacingLeft, mViewSpacingTop, mViewSpacingRight, mViewSpacingBottom); } if (mListView != null) { ((LinearLayout.LayoutParams) customPanel.getLayoutParams()).weight = 0; } } else { mWindow.findViewById(R.id.customPanel).setVisibility(View.GONE); } /* Only display the divider if we have a title and a * custom view or a message. */ if (hasTitle) { View divider = null; if (mMessage != null || mView != null || mListView != null) { divider = mWindow.findViewById(R.id.titleDivider); } else { divider = mWindow.findViewById(R.id.titleDividerTop); } if (divider != null) { divider.setVisibility(View.VISIBLE); } } setBackground(topPanel, contentPanel, customPanel, hasButtons, a, hasTitle, buttonPanel); a.recycle(); } 其中又相继调用了setupContent()、setupTitle()、setBackground()、setupButtons()等方法，分别设置内容部分、标题部分、背景、底部等。
先看下setupContent()方法：
private void setupContent(LinearLayout contentPanel) { mScrollView = (ScrollView) mWindow.findViewById(R.id.scrollView); mScrollView.setFocusable(false); // Special case for users that only want to display a String mMessageView = (TextView) mWindow.findViewById(R.id.message); if (mMessageView == null) { return; } if (mMessage != null) { mMessageView.setText(mMessage); } else { mMessageView.setVisibility(View.GONE); mScrollView.removeView(mMessageView); if (mListView != null) { contentPanel.removeView(mWindow.findViewById(R.id.scrollView)); contentPanel.addView(mListView, new LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT)); contentPanel.setLayoutParams(new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1.0f)); } else { contentPanel.setVisibility(View.GONE); } } } 设置对话框中间显示view内容。
设置底部：
private boolean setupButtons() { int BIT_BUTTON_POSITIVE = 1; int BIT_BUTTON_NEGATIVE = 2; int BIT_BUTTON_NEUTRAL = 4; int whichButtons = 0; mButtonPositive = (Button) mWindow.findViewById(R.id.button1); mButtonPositive.setOnClickListener(mButtonHandler); if (TextUtils.isEmpty(mButtonPositiveText)) { mButtonPositive.setVisibility(View.GONE); } else { mButtonPositive.setText(mButtonPositiveText); mButtonPositive.setVisibility(View.VISIBLE); whichButtons = whichButtons | BIT_BUTTON_POSITIVE; } mButtonNegative = (Button) mWindow.findViewById(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) mWindow.findViewById(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; } 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(mButtonNeutral); } else if (whichButtons == BIT_BUTTON_NEUTRAL) { centerButton(mButtonNeutral); } } return whichButtons != 0; } 设置底部主要是对话框按钮这一部分区域的设置，里面调用了centerButton方法：
private void centerButton(Button button) { LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) button.getLayoutParams(); params.gravity = Gravity.CENTER_HORIZONTAL; params.weight = 0.5f; button.setLayoutParams(params); View leftSpacer = mWindow.findViewById(R.id.leftSpacer); if (leftSpacer != null) { leftSpacer.setVisibility(View.VISIBLE); } View rightSpacer = mWindow.findViewById(R.id.rightSpacer); if (rightSpacer != null) { rightSpacer.setVisibility(View.VISIBLE); } } 设置button水平居中。在setupButton代码注释里面也说了：如果只有一个button，设置其居中并占据可用区域的一半。
再来看一下setupTitle()：
private boolean setupTitle(LinearLayout topPanel) { boolean hasTitle = true; if (mCustomTitleView != null) { // Add the custom title view directly to the topPanel layout LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams( LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.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 { final boolean hasTextTitle = !TextUtils.isEmpty(mTitle); mIconView = (ImageView) mWindow.findViewById(R.id.icon); if (hasTextTitle) { /* 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 if (mIconId == 0) { /* 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 View titleTemplate = mWindow.findViewById(R.id.title_template); titleTemplate.setVisibility(View.GONE); mIconView.setVisibility(View.GONE); topPanel.setVisibility(View.GONE); hasTitle = false; } } return hasTitle; } 首先，如果设置了自定义的顶部视图，就是用自定义视图，并隐藏标题模板视图。否则使用默认视图设置其顶部显示标题文字，图片的内容，如果没有标题文字，也隐藏标题模板视图。
后面是setBackground():
private void setBackground(LinearLayout topPanel, LinearLayout contentPanel, View customPanel, boolean hasButtons, TypedArray a, boolean hasTitle, View buttonPanel) { /* Get all the different background required */ int fullDark = a.getResourceId( R.styleable.AlertDialog_fullDark, R.drawable.popup_full_dark); int topDark = a.getResourceId( R.styleable.AlertDialog_topDark, R.drawable.popup_top_dark); int centerDark = a.getResourceId( R.styleable.AlertDialog_centerDark, R.drawable.popup_center_dark); int bottomDark = a.getResourceId( R.styleable.AlertDialog_bottomDark, R.drawable.popup_bottom_dark); int fullBright = a.getResourceId( R.styleable.AlertDialog_fullBright, R.drawable.popup_full_bright); int topBright = a.getResourceId( R.styleable.AlertDialog_topBright, R.drawable.popup_top_bright); int centerBright = a.getResourceId( R.styleable.AlertDialog_centerBright, R.drawable.popup_center_bright); int bottomBright = a.getResourceId( R.styleable.AlertDialog_bottomBright, R.drawable.popup_bottom_bright); int bottomMedium = a.getResourceId( R.styleable.AlertDialog_bottomMedium, R.drawable.popup_bottom_medium); /* * We now set the background of all of the sections of the alert. * First collect together each section that is being displayed along * with whether it is on a light or dark background, then run through * them setting their backgrounds. This is complicated because we need * to correctly use the full, top, middle, and bottom graphics depending * on how many views they are and where they appear. */ View[] views = new View[4]; boolean[] light = new boolean[4]; View lastView = null; boolean lastLight = false; int pos = 0; if (hasTitle) { views[pos] = topPanel; light[pos] = false; pos++; } /* The contentPanel displays either a custom text message or * a ListView. If it's text we should use the dark background * for ListView we should use the light background. If neither * are there the contentPanel will be hidden so set it as null. */ views[pos] = (contentPanel.getVisibility() == View.GONE) ? null : contentPanel; light[pos] = mListView != null; pos++; if (customPanel != null) { views[pos] = customPanel; light[pos] = mForceInverseBackground; pos++; } if (hasButtons) { views[pos] = buttonPanel; light[pos] = true; } boolean setView = false; for (pos=0; pos<views.length; pos++) { View v = views[pos]; if (v == null) { continue; } if (lastView != null) { if (!setView) { lastView.setBackgroundResource(lastLight ? topBright : topDark); } else { lastView.setBackgroundResource(lastLight ? centerBright : centerDark); } setView = true; } lastView = v; lastLight = light[pos]; } if (lastView != null) { if (setView) { /* ListViews will use the Bright background but buttons use * the Medium background. */ lastView.setBackgroundResource( lastLight ? (hasButtons ? bottomMedium : bottomBright) : bottomDark); } else { lastView.setBackgroundResource(lastLight ? fullBright : fullDark); } } /* TODO: uncomment section below. The logic for this should be if * it's a Contextual menu being displayed AND only a Cancel button * is shown then do this. */// if (hasButtons && (mListView != null)) { /* Yet another *special* case. If there is a ListView with buttons * don't put the buttons on the bottom but instead put them in the * footer of the ListView this will allow more items to be * displayed. */ /* contentPanel.setBackgroundResource(bottomBright); buttonPanel.setBackgroundResource(centerMedium); ViewGroup parent = (ViewGroup) mWindow.findViewById(R.id.parentPanel); parent.removeView(buttonPanel); AbsListView.LayoutParams params = new AbsListView.LayoutParams( AbsListView.LayoutParams.MATCH_PARENT, AbsListView.LayoutParams.MATCH_PARENT); buttonPanel.setLayoutParams(params); mListView.addFooterView(buttonPanel); */// } if ((mListView != null) && (mAdapter != null)) { mListView.setAdapter(mAdapter); if (mCheckedItem > -1) { mListView.setItemChecked(mCheckedItem, true); mListView.setSelection(mCheckedItem); } } } 首先是获取不同的背景需求，然后去设置对话框不同部分的背景色，首先使用下面代码收集起来各个部分的背景情况（或明或暗）然后根据不同视图的显示设置其顶部、中部、底部的背景。
View[] views = new View[4]; boolean[] light = new boolean[4]; View lastView = null; boolean lastLight = false; int pos = 0; if (hasTitle) { views[pos] = topPanel; light[pos] = false; pos++; } 如果其内容视图显示一个自定义文本或者一个ListView，文本应设置为深色背景，而ListView应设置为浅色背景，如没有内容视图，则设置其背景为null。
views[pos] = (contentPanel.getVisibility() == View.GONE) ? null : contentPanel; light[pos] = mListView != null; pos++; if (customPanel != null) { views[pos] = customPanel; light[pos] = mForceInverseBackground; pos++; } if (hasButtons) { views[pos] = buttonPanel; light[pos] = true; } boolean setView = false; for (pos=0; pos<views.length; pos++) { View v = views[pos]; if (v == null) { continue; } if (lastView != null) { if (!setView) { lastView.setBackgroundResource(lastLight ? topBright : topDark); } else { lastView.setBackgroundResource(lastLight ? centerBright : centerDark); } setView = true; } lastView = v; lastLight = light[pos]; } if (lastView != null) { if (setView) { /* ListViews will use the Bright background but buttons use * the Medium background. Listview应明亮些，button应该偏中色背景 */ lastView.setBackgroundResource( lastLight ? (hasButtons ? bottomMedium : bottomBright) : bottomDark); } else { lastView.setBackgroundResource(lastLight ? fullBright : fullDark); } } 再回到247行，看一些其他设置，设置标题：
public void setTitle(CharSequence title) { mTitle = title; if (mTitleView != null) { mTitleView.setText(title); } } 设置自定义标题：
/** * @see AlertDialog.Builder#setCustomTitle(View) */ public void setCustomTitle(View customTitleView) { mCustomTitleView = customTitleView; } 设置显示信息：
public void setMessage(CharSequence message) { mMessage = message; if (mMessageView != null) { mMessageView.setText(message); } } 设置Dialog自定义视图：
/** * Set the view to display in the dialog. */ public void setView(View view) { mView = view; mViewSpacingSpecified = false; } /** * Set the view to display in the dialog along with the spacing around that view */ public void setView(View view, int viewSpacingLeft, int viewSpacingTop, int viewSpacingRight, int viewSpacingBottom) { mView = view; mViewSpacingSpecified = true; mViewSpacingLeft = viewSpacingLeft; mViewSpacingTop = viewSpacingTop; mViewSpacingRight = viewSpacingRight; mViewSpacingBottom = viewSpacingBottom; } 这个方法可以设置视图到上下左右的间距。
设置按钮和其点击后传送的消息内容：
/** * Sets a click listener or a message to be sent when the button is clicked. * You only need to pass one of {@code listener} or {@code msg}. * * @param whichButton Which button, can be one of * {@link DialogInterface#BUTTON_POSITIVE}, * {@link DialogInterface#BUTTON_NEGATIVE}, or * {@link DialogInterface#BUTTON_NEUTRAL} * @param text The text to display in positive button. * @param listener The {@link DialogInterface.OnClickListener} to use. * @param msg The {@link Message} to be sent when clicked. */ public void setButton(int whichButton, CharSequence text, DialogInterface.OnClickListener listener, Message msg) { if (msg == null && listener != null) { msg = mHandler.obtainMessage(whichButton, listener); } switch (whichButton) { case DialogInterface.BUTTON_POSITIVE: mButtonPositiveText = text; mButtonPositiveMessage = msg; break; case DialogInterface.BUTTON_NEGATIVE: mButtonNegativeText = text; mButtonNegativeMessage = msg; break; case DialogInterface.BUTTON_NEUTRAL: mButtonNeutralText = text; mButtonNeutralMessage = msg; break; default: throw new IllegalArgumentException("Button does not exist"); } } 设置对话框图标：
/** * Set resId to 0 if you don't want an icon. * @param resId the resourceId of the drawable to use as the icon or 0 * if you don't want an icon. */ public void setIcon(int resId) { mIconId = resId; if (mIconView != null) { if (resId > 0) { mIconView.setImageResource(mIconId); } else if (resId == 0) { mIconView.setVisibility(View.GONE); } } } public void setIcon(Drawable icon) { mIcon = icon; if ((mIconView != null) && (mIcon != null)) { mIconView.setImageDrawable(icon); } } 设置对话框后面的窗体是否能够获得焦点（能不能响应用户操作触发的事件）： public void setInverseBackgroundForced(boolean forceInverseBackground) { mForceInverseBackground = forceInverseBackground; }
获取对话框提供的ListView:
public ListView getListView() { return mListView; }
获取按钮：
public Button getButton(int whichButton) { switch (whichButton) { case DialogInterface.BUTTON_POSITIVE: return mButtonPositive; case DialogInterface.BUTTON_NEGATIVE: return mButtonNegative; case DialogInterface.BUTTON_NEUTRAL: return mButtonNeutral; default: return null; } }
按下或者抬起事件：
@SuppressWarnings({"UnusedDeclaration"}) public boolean onKeyDown(int keyCode, KeyEvent event) { return mScrollView != null && mScrollView.executeKeyEvent(event); } @SuppressWarnings({"UnusedDeclaration"}) public boolean onKeyUp(int keyCode, KeyEvent event) { return mScrollView != null && mScrollView.executeKeyEvent(event); }下面定义了一个静态内部类：RecycleListView（此listView Measure状态下回收视图）public static class RecycleListView extends ListView { boolean mRecycleOnMeasure = true; public RecycleListView(Context context) { super(context); } public RecycleListView(Context context, AttributeSet attrs) { super(context, attrs); } public RecycleListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override protected boolean recycleOnMeasure() { return mRecycleOnMeasure; } }
还剩下最后一个静态内部类：AlertParams
public static class AlertParams { public final Context mContext; public final LayoutInflater mInflater; public int mIconId = 0; public Drawable mIcon; public CharSequence mTitle; public View mCustomTitleView; public CharSequence mMessage; public CharSequence mPositiveButtonText; public DialogInterface.OnClickListener mPositiveButtonListener; public CharSequence mNegativeButtonText; public DialogInterface.OnClickListener mNegativeButtonListener; public CharSequence mNeutralButtonText; public DialogInterface.OnClickListener mNeutralButtonListener; public boolean mCancelable; public DialogInterface.OnCancelListener mOnCancelListener; public DialogInterface.OnKeyListener mOnKeyListener; public CharSequence[] mItems; public ListAdapter mAdapter; public DialogInterface.OnClickListener mOnClickListener; public View mView; public int mViewSpacingLeft; public int mViewSpacingTop; public int mViewSpacingRight; public int mViewSpacingBottom; public boolean mViewSpacingSpecified = false; public boolean[] mCheckedItems; public boolean mIsMultiChoice; public boolean mIsSingleChoice; public int mCheckedItem = -1; public DialogInterface.OnMultiChoiceClickListener mOnCheckboxClickListener; public Cursor mCursor; public String mLabelColumn; public String mIsCheckedColumn; public boolean mForceInverseBackground; public AdapterView.OnItemSelectedListener mOnItemSelectedListener; public OnPrepareListViewListener mOnPrepareListViewListener; public boolean mRecycleOnMeasure = true; /** * Interface definition for a callback to be invoked before the ListView * will be bound to an adapter. */ public interface OnPrepareListViewListener { /** * Called before the ListView is bound to an adapter. * @param listView The ListView that will be shown in the dialog. */ void onPrepareListView(ListView listView); } public AlertParams(Context context) { mContext = context; mCancelable = true; mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); } 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 (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); } if (mForceInverseBackground) { dialog.setInverseBackgroundForced(true); } // For a list, the client can either supply an array of items or an // adapter or a cursor if ((mItems != null) || (mCursor != null) || (mAdapter != null)) { createListView(dialog); } if (mView != null) { if (mViewSpacingSpecified) { dialog.setView(mView, mViewSpacingLeft, mViewSpacingTop, mViewSpacingRight, mViewSpacingBottom); } else { dialog.setView(mView); } } /* dialog.setCancelable(mCancelable); dialog.setOnCancelListener(mOnCancelListener); if (mOnKeyListener != null) { dialog.setOnKeyListener(mOnKeyListener); } */ } private void createListView(final AlertController dialog) { final RecycleListView listView = (RecycleListView) mInflater.inflate(dialog.mListLayout, null); ListAdapter adapter; if (mIsMultiChoice) { if (mCursor == null) { adapter = new ArrayAdapter<CharSequence>( mContext, dialog.mMultiChoiceItemLayout, R.id.text1, mItems) { @Override public View getView(int position, View convertView, ViewGroup parent) { View view = super.getView(position, convertView, parent); if (mCheckedItems != null) { boolean isItemChecked = mCheckedItems[position]; if (isItemChecked) { listView.setItemChecked(position, true); } } return view; } }; } else { adapter = new CursorAdapter(mContext, mCursor, false) { private final int mLabelIndex; private final int mIsCheckedIndex; { final Cursor cursor = getCursor(); mLabelIndex = cursor.getColumnIndexOrThrow(mLabelColumn); mIsCheckedIndex = cursor.getColumnIndexOrThrow(mIsCheckedColumn); } @Override public void bindView(View view, Context context, Cursor cursor) { CheckedTextView text = (CheckedTextView) view.findViewById(R.id.text1); text.setText(cursor.getString(mLabelIndex)); listView.setItemChecked(cursor.getPosition(), cursor.getInt(mIsCheckedIndex) == 1); } @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { return mInflater.inflate(dialog.mMultiChoiceItemLayout, parent, false); } }; } } else { int layout = mIsSingleChoice ? dialog.mSingleChoiceItemLayout : dialog.mListItemLayout; if (mCursor == null) { adapter = (mAdapter != null) ? mAdapter : new ArrayAdapter<CharSequence>(mContext, layout, R.id.text1, mItems); } else { adapter = new SimpleCursorAdapter(mContext, layout, mCursor, new String[]{mLabelColumn}, new int[]{R.id.text1}); } } if (mOnPrepareListViewListener != null) { mOnPrepareListViewListener.onPrepareListView(listView); } /* Don't directly set the adapter on the ListView as we might * want to add a footer to the ListView later. */ dialog.mAdapter = adapter; dialog.mCheckedItem = mCheckedItem; if (mOnClickListener != null) { listView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View v, int position, long id) { mOnClickListener.onClick(dialog.mDialogInterface, position); if (!mIsSingleChoice) { dialog.mDialogInterface.dismiss(); } } }); } else if (mOnCheckboxClickListener != null) { listView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View v, int position, long id) { if (mCheckedItems != null) { mCheckedItems[position] = listView.isItemChecked(position); } mOnCheckboxClickListener.onClick( dialog.mDialogInterface, position, listView.isItemChecked(position)); } }); } // Attach a given OnItemSelectedListener to the ListView if (mOnItemSelectedListener != null) { listView.setOnItemSelectedListener(mOnItemSelectedListener); } if (mIsSingleChoice) { listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE); } else if (mIsMultiChoice) { listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE); } listView.mRecycleOnMeasure = mRecycleOnMeasure; dialog.mListView = listView; } }绝大多数参数都比较简单，从字面意思就可以看明白，挑选几个参数简单说明一下：
mWindow：窗体类
mListView：可以对外提供一个ListView
mViewSpacingLeft：设置视图左边间隔
mViewSpacingSpecified：视图是否是指定间距（默认为false）
mCheckedItems：bool值，多选框是否被选中
mIsMultiChoice：是否是多选
可以简单的认为AlertParams类为AlertController的工具类，看下其里面的两个方法，第一个apply：
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 (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); } if (mForceInverseBackground) { dialog.setInverseBackgroundForced(true); } // For a list, the client can either supply an array of items or an // adapter or a cursor if ((mItems != null) || (mCursor != null) || (mAdapter != null)) { createListView(dialog); } if (mView != null) { if (mViewSpacingSpecified) { dialog.setView(mView, mViewSpacingLeft, mViewSpacingTop, mViewSpacingRight, mViewSpacingBottom); } else { dialog.setView(mView); } } /* dialog.setCancelable(mCancelable); dialog.setOnCancelListener(mOnCancelListener); if (mOnKeyListener != null) { dialog.setOnKeyListener(mOnKeyListener); } */ } 为Dialog设置各种属性，在AlertDialog.Builder的create（）方法中调用了该方法。
为Dialog创建一个listView：
private void createListView(final AlertController dialog) { final RecycleListView listView = (RecycleListView) mInflater.inflate(dialog.mListLayout, null); ListAdapter adapter; //是否是多选 if (mIsMultiChoice) { //是否是从数据库中取出的值 if (mCursor == null) { adapter = new ArrayAdapter<CharSequence>( mContext, dialog.mMultiChoiceItemLayout, R.id.text1, mItems) { @Override public View getView(int position, View convertView, ViewGroup parent) { View view = super.getView(position, convertView, parent); if (mCheckedItems != null) { boolean isItemChecked = mCheckedItems[position]; if (isItemChecked) { listView.setItemChecked(position, true); } } return view; } }; } else { adapter = new CursorAdapter(mContext, mCursor, false) { private final int mLabelIndex; private final int mIsCheckedIndex; { final Cursor cursor = getCursor(); mLabelIndex = cursor.getColumnIndexOrThrow(mLabelColumn); mIsCheckedIndex = cursor.getColumnIndexOrThrow(mIsCheckedColumn); } @Override public void bindView(View view, Context context, Cursor cursor) { CheckedTextView text = (CheckedTextView) view.findViewById(R.id.text1); text.setText(cursor.getString(mLabelIndex)); listView.setItemChecked(cursor.getPosition(), cursor.getInt(mIsCheckedIndex) == 1); } @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { return mInflater.inflate(dialog.mMultiChoiceItemLayout, parent, false); } }; } } else {//如果是单选或者普通的listview int layout = mIsSingleChoice ? dialog.mSingleChoiceItemLayout : dialog.mListItemLayout; if (mCursor == null) { adapter = (mAdapter != null) ? mAdapter : new ArrayAdapter<CharSequence>(mContext, layout, R.id.text1, mItems); } else { adapter = new SimpleCursorAdapter(mContext, layout, mCursor, new String[]{mLabelColumn}, new int[]{R.id.text1}); } } if (mOnPrepareListViewListener != null) { mOnPrepareListViewListener.onPrepareListView(listView); } /* Don't directly set the adapter on the ListView as we might * want to add a footer to the ListView later. * 不要直接为listView设置adapter，因为一会可能需要为listView设置页脚 */ dialog.mAdapter = adapter; dialog.mCheckedItem = mCheckedItem; //设置监听 if (mOnClickListener != null) { listView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View v, int position, long id) { mOnClickListener.onClick(dialog.mDialogInterface, position); if (!mIsSingleChoice) { dialog.mDialogInterface.dismiss(); } } }); } else if (mOnCheckboxClickListener != null) { //多选监听 listView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View v, int position, long id) { if (mCheckedItems != null) { mCheckedItems[position] = listView.isItemChecked(position); } mOnCheckboxClickListener.onClick( dialog.mDialogInterface, position, listView.isItemChecked(position)); } }); } // Attach a given OnItemSelectedListener to the ListView if (mOnItemSelectedListener != null) { listView.setOnItemSelectedListener(mOnItemSelectedListener); } //如有选择项，选择单选或者多选 if (mIsSingleChoice) { listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE); } else if (mIsMultiChoice) { listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE); } listView.mRecycleOnMeasure = mRecycleOnMeasure; dialog.mListView = listView; } } 这个方法逻辑注释在代码中，不详细解释了，都比较简单。
看AlertController源码，可以结合AlertDialog源码看。因为在AlertDialog中的大部分功能实现是靠调用AlertController类来实现。
更多源码解析：Android源码解析
PS：终于简单的把这篇源码看完，距离AlertDialog已经有一个月了，时间飞快，多需努力，我想回家。
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