Android修改Dialog樣式

Android 對話框支持自定義標題，內容，按鈕和點擊事件，基本上能夠知足咱們平常的使用。但有時候咱們想要修改對話框的文字，按鈕顏色等，系統並無提供對應的方法，正常狀況下只能自定義佈局。接下來經過源碼解析介紹幾種修改 Dialog樣式的方法。java

1、Dialog源碼解析

1.1 new AlertDialog.Builder(this).create()

protected AlertDialog(@NonNull Context context, @StyleRes int themeResId) {
        super(context, resolveDialogTheme(context, themeResId));
        //建立AlertController，是Dialog佈局相關代碼
        mAlert = new AlertController(getContext(), this, getWindow());
    }

        @NonNull
        public AlertDialog create() {
            // We can't use Dialog's 3-arg constructor with the createThemeContextWrapper param,
            // so we always have to re-set the theme
            final AlertDialog dialog = new AlertDialog(P.mContext, mTheme);
            P.apply(dialog.mAlert);
            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;
        }

        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);
                }
            ..........
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AlertDialog 構造函數中會建立 AlertController，用來控制對話框的佈局
P.apply(dialog.mAlert); 將用戶自定義的配置賦值給 AlertController

1.2 AlertController

public AlertController(Context context, AppCompatDialog di, Window window) {
        mContext = context;
        mDialog = di;
        mWindow = window;
        mHandler = new ButtonHandler(di);

        final TypedArray a = context.obtainStyledAttributes(null, R.styleable.AlertDialog,
                R.attr.alertDialogStyle, 0);

        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);
        mButtonIconDimen = a.getDimensionPixelSize(R.styleable.AlertDialog_buttonIconDimen, 0);

        a.recycle();

        /* We use a custom title so never request a window title */
        di.supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
    }
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R.attr.alertDialogStyle 是對話框的默認樣式，android

<item name="alertDialogStyle">@style/AlertDialog.AppCompat</item>
        <style name="AlertDialog.AppCompat" parent="Base.AlertDialog.AppCompat"/> <style name="Base.AlertDialog.AppCompat" parent="android:Widget"> <item name="android:layout">@layout/abc_alert_dialog_material</item> <item name="listLayout">@layout/abc_select_dialog_material</item> <item name="listItemLayout">@layout/select_dialog_item_material</item> <item name="multiChoiceItemLayout">@layout/select_dialog_multichoice_material</item> <item name="singleChoiceItemLayout">@layout/select_dialog_singlechoice_material</item> <item name="buttonIconDimen">@dimen/abc_alert_dialog_button_dimen</item> </style>      
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上述代碼能夠看出，abc_alert_dialog_material 就是dialog的默認佈局。markdown

<androidx.appcompat.widget.AlertDialogLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/parentPanel" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="start|left|top" android:orientation="vertical">

    <include layout="@layout/abc_alert_dialog_title_material"/>

    <FrameLayout android:id="@+id/contentPanel" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="48dp">

        <View android:id="@+id/scrollIndicatorUp" android:layout_width="match_parent" android:layout_height="1dp" android:layout_gravity="top" android:background="?attr/colorControlHighlight" android:visibility="gone"/>

        <androidx.core.widget.NestedScrollView android:id="@+id/scrollView" android:layout_width="match_parent" android:layout_height="wrap_content" android:clipToPadding="false">

            <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical">

                <android.widget.Space android:id="@+id/textSpacerNoTitle" android:layout_width="match_parent" android:layout_height="@dimen/abc_dialog_padding_top_material" android:visibility="gone"/>

                <TextView android:id="@android:id/message" style="@style/TextAppearance.AppCompat.Subhead" android:layout_width="match_parent" android:layout_height="wrap_content" android:paddingLeft="?attr/dialogPreferredPadding" android:paddingRight="?attr/dialogPreferredPadding"/>

                <android.widget.Space android:id="@+id/textSpacerNoButtons" android:layout_width="match_parent" android:layout_height="@dimen/abc_dialog_padding_top_material" android:visibility="gone"/>
            </LinearLayout>
        </androidx.core.widget.NestedScrollView>

        <View android:id="@+id/scrollIndicatorDown" android:layout_width="match_parent" android:layout_height="1dp" android:layout_gravity="bottom" android:background="?attr/colorControlHighlight" android:visibility="gone"/>

    </FrameLayout>

    <FrameLayout android:id="@+id/customPanel" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="48dp">

        <FrameLayout android:id="@+id/custom" android:layout_width="match_parent" android:layout_height="wrap_content"/>
    </FrameLayout>

    <include layout="@layout/abc_alert_dialog_button_bar_material" android:layout_width="match_parent" android:layout_height="wrap_content"/>

</androidx.appcompat.widget.AlertDialogLayout>
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標題佈局：app

<!-- abc_alert_dialog_title_material: -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/topPanel" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical">

    <!-- If the client uses a customTitle, it will be added here. -->

    <LinearLayout android:id="@+id/title_template" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center_vertical|start|left" android:orientation="horizontal" android:paddingLeft="?attr/dialogPreferredPadding" android:paddingRight="?attr/dialogPreferredPadding" android:paddingTop="@dimen/abc_dialog_padding_top_material">

        <ImageView android:id="@android:id/icon" android:layout_width="32dip" android:layout_height="32dip" android:layout_marginEnd="8dip" android:layout_marginRight="8dip" android:scaleType="fitCenter" android:src="@null"/>

        <androidx.appcompat.widget.DialogTitle android:id="@+id/alertTitle" style="?android:attr/windowTitleStyle" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_gravity="start" android:ellipsize="end" android:singleLine="true" android:textAlignment="viewStart"/>

    </LinearLayout>

    <android.widget.Space android:id="@+id/titleDividerNoCustom" android:layout_width="match_parent" android:layout_height="@dimen/abc_dialog_title_divider_material" android:visibility="gone"/>
</LinearLayout>
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按鈕佈局：ide

<!-- abc_alert_dialog_button_bar_material: -->
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/buttonPanel" style="?attr/buttonBarStyle" android:layout_width="match_parent" android:layout_height="wrap_content" android:fillViewport="true" android:scrollIndicators="top|bottom">

    <androidx.appcompat.widget.ButtonBarLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="bottom" android:layoutDirection="locale" android:orientation="horizontal" android:paddingBottom="4dp" android:paddingLeft="12dp" android:paddingRight="12dp" android:paddingTop="4dp">

        <Button android:id="@android:id/button3" style="?attr/buttonBarNeutralButtonStyle" android:layout_width="wrap_content" android:layout_height="wrap_content"/>

        <android.widget.Space android:id="@+id/spacer" android:layout_width="0dp" android:layout_height="0dp" android:layout_weight="1" android:visibility="invisible"/>

        <Button android:id="@android:id/button2" style="?attr/buttonBarNegativeButtonStyle" android:layout_width="wrap_content" android:layout_height="wrap_content"/>

        <Button android:id="@android:id/button1" style="?attr/buttonBarPositiveButtonStyle" android:layout_width="wrap_content" android:layout_height="wrap_content"/>

    </androidx.appcompat.widget.ButtonBarLayout>

</ScrollView>
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2、修改Dialog樣式

2.1 經過findViewById

AlertDialog.Builder builder = new AlertDialog.Builder(this);
      builder.setMessage(msg);
      builder.setPositiveButton(getString(R.string.yes), null);
      AlertDialog dialog = builder.create();
      dialog.show();
      //直接經過id找到對應的控件
      Button button = dialog.findViewById(android.R.id.button1);
      //或者經過getButton方法也能夠獲取到
      Button button2 = dialog.getButton(DialogInterface.BUTTON_POSITIVE);
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這種修改方式必須在 show() 以後調用，不然會出現空指針異常。這個是由於，執行 show() 方法的時候，dialog纔會初始化佈局，具體源碼能夠查看 Dialog 的 onCreate 方法。函數

2.2 自定義style

經過上面源碼能夠發現，Dialog三個按鈕的樣式以下：佈局

buttonBarNeutralButtonStyle
buttonBarNegativeButtonStyle
buttonBarPositiveButtonStyle

<Button android:id="@android:id/button3" style="?attr/buttonBarNeutralButtonStyle" android:layout_width="wrap_content" android:layout_height="wrap_content"/>

        <android.widget.Space android:id="@+id/spacer" android:layout_width="0dp" android:layout_height="0dp" android:layout_weight="1" android:visibility="invisible"/>

        <Button android:id="@android:id/button2" style="?attr/buttonBarNegativeButtonStyle" android:layout_width="wrap_content" android:layout_height="wrap_content"/>

        <Button android:id="@android:id/button1" style="?attr/buttonBarPositiveButtonStyle" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
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自定義樣式替換上述 style便可達到修改效果。ui

在style.xml添加以下代碼：

<style name="accessPositiveBtnStyle" parent="Widget.AppCompat.Button.ButtonBar.AlertDialog"> <item name="android:textColor">@color/test1</item> </style>

    <style name="accessNegativeBtnStyle" parent="Widget.AppCompat.Button.ButtonBar.AlertDialog"> <item name="android:textColor">@color/test2</item> </style>

    <!-- 彈出框樣式 -->
    <style name="testDialogTheme" parent="Theme.AppCompat.Light.Dialog.Alert"> <item name="buttonBarPositiveButtonStyle">@style/accessPositiveBtnStyle</item> <item name="buttonBarNegativeButtonStyle">@style/accessNegativeBtnStyle</item> </style>
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具體使用：

AlertDialog.Builder builder = new AlertDialog.Builder(this, R.style.testDialogTheme);
    builder.setMessage("Test");
    builder.setCancelable(false);
    builder.setPositiveButton("確認", null);
    builder.setNegativeButton("取消", null);
    Dialog dialog = builder.create();
    dialog.show();
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