Android ApiDemos示例解析(4):App->Activity->Custom Dialog

第四篇：http://blog.csdn.net/mapdigit/article/details/7570371

App->Activity->Custom Dialog

这个Demo主要是实现自定义对话框。

先通过Android Manifest.xml文件找到CustomDialogActivity：

<activity android:name=".app.CustomDialogActivity"
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android:label="@string/activity_custom_dialog"
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android:theme="@style/Theme.CustomDialog">
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<intent-filter>
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<action android:name="android.intent.action.MAIN" />
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<category android:name="android.intent.category.SAMPLE_CODE" />
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</intent-filter>
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</activity>

我们看到CustomDialogActivity设置了一个Theme，去styles.xml看看是怎么定义的。

<!-- A theme for a custom dialog appearance. Here we use an ugly
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custom frame. -->
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<item name="android:windowBackground">@drawable/filled_box</item>
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</style>

Android应用可以使用自定义的界面风格（Theme），Theme 为一组相关的Style定义，可以应用于某个Activity或是整个Application。使用Theme的一个好处是可以为整个应用定义统一的界面风格（统一的背景色，字体等）。

定义Theme 和定义Style一样，必须定义在/res/values子目录下，根元素名为resources, Theme 和Style的区别在于Theme应用于Activity和Application，而 Style应用于单个的View。其定义方法是一致的。

上面定义的Theme.CustomDialog主题继承了android.R.style.Theme.Dialog主题，同时覆盖了android:windowBackground属性。

我们去源代码文件

frameworks / base / core / res / res / values / themes.xml下找到Theme.Dialog:

<item name="android:windowFrame">@null</item>
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<item name="android:windowTitleStyle">@android:style/DialogWindowTitle</item>
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<item name="android:windowBackground">@android:drawable/panel_background</item>
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<item name="android:windowIsFloating">true</item>
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<item name="android:windowContentOverlay">@null</item>
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<item name="android:windowAnimationStyle">@android:style/Animation.Dialog</item>
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<item name="android:windowSoftInputMode">stateUnspecified|adjustPan</item>
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<item name="android:windowCloseOnTouchOutside">@bool/config_closeDialogWhenTouchOutside</item>
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<item name="android:windowActionModeOverlay">true</item>
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<item name="android:colorBackgroundCacheHint">@null</item>
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<item name="textAppearance">@android:style/TextAppearance</item>
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<item name="textAppearanceInverse">@android:style/TextAppearance.Inverse</item>
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<item name="textColorPrimary">@android:color/primary_text_dark</item>
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<item name="textColorSecondary">@android:color/secondary_text_dark</item>
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<item name="textColorTertiary">@android:color/tertiary_text_dark</item>
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<item name="textColorPrimaryInverse">@android:color/primary_text_light</item>
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<item name="textColorSecondaryInverse">@android:color/secondary_text_light</item>
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<item name="textColorTertiaryInverse">@android:color/tertiary_text_light</item>
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<item name="textColorPrimaryDisableOnly">@android:color/primary_text_dark_disable_only</item>
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<item name="textColorPrimaryInverseDisableOnly">@android:color/primary_text_light_disable_only</item>
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<item name="textColorPrimaryNoDisable">@android:color/primary_text_dark_nodisable</item>
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<item name="textColorSecondaryNoDisable">@android:color/secondary_text_dark_nodisable</item>
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<item name="textColorPrimaryInverseNoDisable">@android:color/primary_text_light_nodisable</item>
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<item name="textColorSecondaryInverseNoDisable">@android:color/secondary_text_light_nodisable</item>
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<item name="textColorHint">@android:color/hint_foreground_dark</item>
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<item name="textColorHintInverse">@android:color/hint_foreground_light</item>
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<item name="textColorSearchUrl">@android:color/search_url_text</item>
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<item name="textAppearanceLarge">@android:style/TextAppearance.Large</item>
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<item name="textAppearanceMedium">@android:style/TextAppearance.Medium</item>
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<item name="textAppearanceSmall">@android:style/TextAppearance.Small</item>
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<item name="textAppearanceLargeInverse">@android:style/TextAppearance.Large.Inverse</item>
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<item name="textAppearanceMediumInverse">@android:style/TextAppearance.Medium.Inverse</item>
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<item name="textAppearanceSmallInverse">@android:style/TextAppearance.Small.Inverse</item>
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<item name="listPreferredItemPaddingLeft">10dip</item>
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<item name="listPreferredItemPaddingRight">10dip</item>
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</style>

它定义了很多属性，就不详细讲了。

我们再去看看filled_box.xml是怎么定义的。

<?xml version="1.0" encoding="utf-8"?>
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<!--
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** Copyright 2007, The Android Open Source Project
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**
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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**
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** http://www.apache.org/licenses/LICENSE-2.0
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**
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*/
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-->
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<shape xmlns:android="http://schemas.android.com/apk/res/android">
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<solid android:color="#f0600000"/>
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<stroke android:width="3dp" color="#ffff8080"/>
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<corners android:radius="3dp" />
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<padding android:left="10dp" android:top="10dp"
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android:right="10dp" android:bottom="10dp" />
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</shape>

Shape
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简介
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作用：XML中定义的几何形状
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位置：res/drawable/文件的名称.xml
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使用的方法：
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Java代码中：R.drawable.文件的名称
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XML中：Android:background="@drawable/文件的名称"
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属性：
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<shape> Android:shape=["rectangle" | "oval" | "line" | "ring"]
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其中rectagle矩形，oval椭圆，line水平直线，ring环形
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<shape>中子节点的常用属性：
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<gradient> 渐变
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Android:startColor 起始颜色
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Android:endColor 结束颜色
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Android:angle 渐变角度，0从上到下，90表示从左到右，数值为45的整数倍默认为0；
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Android:type 渐变的样式 liner线性渐变 radial环形渐变 sweep
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<solid > 填充
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Android:color 填充的颜色
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<stroke > 描边
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Android:width 描边的宽度
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Android:color 描边的颜色
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Android:dashWidth 表示'-'横线的宽度
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Android:dashGap 表示'-'横线之间的距离
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<corners > 圆角
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Android:radius 圆角的半径值越大角越圆
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Android:topRightRadius 右上圆角半径
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Android:bottomLeftRadius 右下圆角角半径
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Android:topLeftRadius 左上圆角半径
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Android:bottomRightRadius 左下圆角半径

找到CustomDialogActivity.java 只是设置了布局文件。

/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.apis.app;
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// Need the following import to get access to the app resources, since this
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// class is in a sub-package.
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import com.example.android.apis.R;
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import android.app.Activity;
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import android.os.Bundle;
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/**
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* <h3>Dialog Activity</h3>
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*
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* <p>This demonstrates the how to write an activity that looks like
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* a pop-up dialog with a custom theme using a different text color.</p>
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*/
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public class CustomDialogActivity extends Activity {
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/**
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* Initialization of the Activity after it is first created. Must at least
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* call {@link android.app.Activity#setContentView setContentView()} to
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* describe what is to be displayed in the screen.
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*/
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@Override
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protected void onCreate(Bundle savedInstanceState) {
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// Be sure to call the super class.
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super.onCreate(savedInstanceState);
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// See assets/res/any/layout/dialog_activity.xml for this
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// view layout definition, which is being set here as
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// the content of our screen.
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setContentView(R.layout.custom_dialog_activity);
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}
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}

custom_dialog_activity.xml:

<?xml version="1.0" encoding="utf-8"?>
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<!-- Demonstrates an activity with a custom dialog theme.
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See corresponding Java code com.android.sdk.app.CustomDialogActivity.java. -->
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<TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/text"
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android:layout_width="match_parent" android:layout_height="match_parent"
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android:gravity="center_vertical|center_horizontal"
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android:text="@string/custom_dialog_activity_text"/>

android:padding和android:layout_margin的区别？

android:layout_margin就是设置view的上下左右边框的额外空间

android:padding是设置内容相对view的边框的距离

在LinearLayout、RelativeLayout、TableLayout中，这2个属性都是设置都是有效的

在FrameLayout中，android:layout_margin是无效的，因为FrameLayout里面的元素都是从左上角开始绘制的

发表于 2013-05-11 21:27 anthony 阅读(556) 评论(0) 编辑收藏

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