更改Dialog的标题和按钮颜色

摘要：在这个类中第一行就定义了如下变量的功能的具体实现都在这个内部封装修改按钮颜色这里的参数有三种类型传入对应的参数即可得到对应的这种方式只能设置按钮的颜色而无法设置标题颜色需要注意的是这个方法必须在或者方法之后调用查看官方注释的构造函数如下这里

在这个类中第一行就定义了如下变量:

final AlertController mAlert;

AlertDialog的功能的具体实现都在这个AlertController内部封装.

public Button getButton(int whichButton) {
        return mAlert.getButton(whichButton);
    }

这里的参数whichButton有三种类型:

DialogInterface.BUTTON_POSITIVE

DialogInterface.BUTTON_NEGATIVE

DialogInterface.BUTTON_NEUTRAL

传入对应的参数即可得到对应的Button

Button btnPositive = (Button)AlertDialog.getButton(DialogInterface.BUTTON_POSITIVE);
btnPositive.setTextColor(color);

这种方式只能设置按钮的颜色,而无法设置标题颜色

需要注意的是这个方法必须在AlertDialog.show()或者AlertDialog.create()方法之后调用
查看官方注释

/**
     * Gets one of the buttons used in the dialog. Returns null if the specified
     * button does not exist or the dialog has not yet been fully created (for
     * example, via {@link #show()} or {@link #create()}).
     *
     * @param whichButton The identifier of the button that should be returned.
     *                    For example, this can be
     *                    {@link DialogInterface#BUTTON_POSITIVE}.
     * @return The button from the dialog, or null if a button does not exist.
     */
    public Button getButton(int whichButton) {
        return mAlert.getButton(whichButton);
    }

AlertDialog的构造函数如下:

protected AlertDialog(@NonNull Context context, @StyleRes int themeResId) {
        super(context, resolveDialogTheme(context, themeResId));
        mAlert = new AlertController(getContext(), this, getWindow());
    }

这里初始化了AlertController,并传入了getWindow(),这个getWindow()是AlertDialog继承自Dialog的方法.方法如下:

#Dialog.getWindow()
 public @Nullable Window getWindow() {
        return mWindow;
    }

将这个window对象传入AlertController后,在AlertController源码中可以看到对话框标题和按钮的id,并通过Window.findViewById(id)获取对应的View.
所以这里可以这样得到对话框的标题和按钮:

//标题
TextView tvTitle = (TextView)AlertDialog.getWindow().findViewById(R.id.alertTitle);
//按钮
Button btnPositive = (Button)AlertDialog.getWindow().findViewById(R.id.button1);

然后设置所需要的颜色就可以了.这种方法可以修改Dialog的所有设置了id的控件的字体颜色.

3.1 首先拿到AlertController对象

 Field mAlert = AlertDialog.class.getDeclaredField("mAlert");
 mAlert.setAccessible(true);
 Object controller =  mAlert.get(dialog);

在AlertController内部查找到需要更改字体颜色的标题和按钮

Button mButtonPositive;
Button mButtonNegative;
Button mButtonNeutral;
private TextView mTitleView;
private TextView mMessageView;
然后通过反射获取对应控件,修改控件颜色即可

  Field mTitleView = controller.getClass().getDeclaredField("mTitleView");
  mTitleView.setAccessible(true);
  TextView tvTitle = (TextView) mTitleView.get(controller);
  tvTitle.setTextColor(Color.GREEN);//更改标题的颜色

Window window = dialog.getWindow();
 WindowManager.LayoutParams lp = window.getAttributes();
lp.gravity = Gravity.BOTTOM;
lp.x = 100;
lp.y = 100;
window.setAttributes(lp);

这里要注意的是,WindowManager.LayoutParams的x和y坐标,看源码注释如下:

  /**
         * X position for this window.  With the default gravity it is ignored.
         * When using {@link Gravity#LEFT} or {@link Gravity#START} or {@link Gravity#RIGHT} or
         * {@link Gravity#END} it provides an offset from the given edge.
         */
        @ViewDebug.ExportedProperty
        public int x;

        /**
         * Y position for this window.  With the default gravity it is ignored.
         * When using {@link Gravity#TOP} or {@link Gravity#BOTTOM} it provides
         * an offset from the given edge.
         */
        @ViewDebug.ExportedProperty
        public int y;

如果lp.gravity是默认的,那么x和y即使设置了也是无效的.因此x和y需要和lp.gravity搭配使用才有效果.当然lp.gravity也可以多带带使用.