android源码浅析--AlertController
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：
[java]
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）：
[java]
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）。
[java]
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;
&nbs
补充：移动开发 , Android ,
