今天在维护公司的一个APP的时候,有如下场景。
弹出一个AlertDialog的时候，在系统语言是中文的时候，如下所示：
弹出一个AlertDialog的时候，在系统语言是English的时候，如下所示：
可以发现在系统语言为英语的时候，对话框中的白色文字已经完全看不清楚，对话框的背景颜色也变成了白色。因此需要修改对话框的主题。
修改之前代码如下：
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this) .setTitle(title) .setView(vi_nolong) .setPositiveButton( WalkieTalkieActivity.this.getResources().getString(R.string.ok), new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int arg1) { int j = mSelectedGroupNum + 1; int power_last = mIntercomSharePrefs.getInt("CurrentPower_"+j,0); Log.i("wxj", "btn_power CurrentPower_"+j+" :" + power_last); if (power_last == 1) { mEditor.putInt("CurrentPower_"+j,0).commit(); mIntercom.setPowerLevel(0); btn_power.setBackgroundResource(R.drawable.power_high); } else if (power_last == 0) { mEditor.putInt("CurrentPower_"+j,1).commit(); mIntercom.setPowerLevel(1); btn_power.setBackgroundResource(R.drawable.power_low); } dialog.dismiss(); ((ViewGroup) vi_nolong.getParent()).removeView(vi_nolong); } }) .setNegativeButton( WalkieTalkieActivity.this.getResources().getString(R.string.cancel), new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); ((ViewGroup) vi_nolong.getParent()).removeView(vi_nolong); } }).create(); commedialog.setCanceledOnTouchOutside(false); commedialog.show();
可以发现，new AlertDialog.Builder的时候没有指定主题，
AlertDialog commedialog = new AlertDialog.Builder(WalkieTalkieActivity.this)
我们可以在new AlertDialog.Builder的时候指定一个主题，如下所示：
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this,AlertDialog.THEME_HOLO_DARK)
完整代码如下：
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this,AlertDialog.THEME_HOLO_DARK) .setTitle(title) .setView(vi_nolong) .setPositiveButton( WalkieTalkieActivity.this.getResources().getString(R.string.ok), new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int arg1) { int j = mSelectedGroupNum + 1; int power_last = mIntercomSharePrefs.getInt("CurrentPower_"+j,0); Log.i("wxj", "btn_power CurrentPower_"+j+" :" + power_last); if (power_last == 1) { mEditor.putInt("CurrentPower_"+j,0).commit(); mIntercom.setPowerLevel(0); btn_power.setBackgroundResource(R.drawable.power_high); } else if (power_last == 0) { mEditor.putInt("CurrentPower_"+j,1).commit(); mIntercom.setPowerLevel(1); btn_power.setBackgroundResource(R.drawable.power_low); } dialog.dismiss(); ((ViewGroup) vi_nolong.getParent()).removeView(vi_nolong); } }) .setNegativeButton( WalkieTalkieActivity.this.getResources().getString(R.string.cancel), new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); ((ViewGroup) vi_nolong.getParent()).removeView(vi_nolong); } }).create(); commedialog.setCanceledOnTouchOutside(false); commedialog.show();
这样的话就指定了一个黑色背景的主题，这样在系统语言为英语的时候，背景也是黑色的，如下所示：
在系统语言为中文的时候，背景也是黑色的，如下所示：
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下面从源码角度来看看到底是怎么回事，查看AlertDialog.Build代码如下：
/** * Constructor using a context for this builder and the [email protected] AlertDialog} it creates. */ public Builder(Context context) { this(context, resolveDialogTheme(context, 0)); } /** * Constructor using a context and theme for this builder and * the [email protected] AlertDialog} it creates. The actual theme * that an AlertDialog uses is a private implementation, however you can * here supply either the name of an attribute in the theme from which * to get the dialog's style (such as [email protected] android.R.attr#alertDialogTheme} * or one of the constants * [email protected] AlertDialog#THEME_TRADITIONAL AlertDialog.THEME_TRADITIONAL}, * [email protected] AlertDialog#THEME_HOLO_DARK AlertDialog.THEME_HOLO_DARK}, or * [email protected] AlertDialog#THEME_HOLO_LIGHT AlertDialog.THEME_HOLO_LIGHT}. */ public Builder(Context context, int theme) { P = new AlertController.AlertParams(new ContextThemeWrapper( context, resolveDialogTheme(context, theme))); mTheme = theme; }
resolveDialogTheme(Context context, int resid) 代码如下：
static int resolveDialogTheme(Context context, int resid) { if (resid == THEME_TRADITIONAL) { return com.android.internal.R.style.Theme_Dialog_Alert; } else if (resid == THEME_HOLO_DARK) { return com.android.internal.R.style.Theme_Holo_Dialog_Alert; } else if (resid == THEME_HOLO_LIGHT) { return com.android.internal.R.style.Theme_Holo_Light_Dialog_Alert; } else if (resid == THEME_DEVICE_DEFAULT_DARK) { return com.android.internal.R.style.Theme_DeviceDefault_Dialog_Alert; } else if (resid == THEME_DEVICE_DEFAULT_LIGHT) { return com.android.internal.R.style.Theme_DeviceDefault_Light_Dialog_Alert; } else if (resid >= 0x01000000) { // start of real resource IDs. return resid; } else { TypedValue outValue = new TypedValue(); context.getTheme().resolveAttribute(com.android.internal.R.attr.alertDialogTheme, outValue, true); return outValue.resourceId; } }
几个主题的值为：
/** * Special theme constant for [email protected] #AlertDialog(Context, int)}: use * the traditional (pre-Holo) alert dialog theme. */ public static final int THEME_TRADITIONAL = 1; /** * Special theme constant for [email protected] #AlertDialog(Context, int)}: use * the holographic alert theme with a dark background. */ public static final int THEME_HOLO_DARK = 2; /** * Special theme constant for [email protected] #AlertDialog(Context, int)}: use * the holographic alert theme with a light background. */ public static final int THEME_HOLO_LIGHT = 3; /** * Special theme constant for [email protected] #AlertDialog(Context, int)}: use * the device's default alert theme with a dark background. */ public static final int THEME_DEVICE_DEFAULT_DARK = 4; /** * Special theme constant for [email protected] #AlertDialog(Context, int)}: use * the device's default alert theme with a dark background. */ public static final int THEME_DEVICE_DEFAULT_LIGHT = 5;
由此可见，当我们不指定主题的时候，
AlertDialog commedialog = new AlertDialog.Builder(WalkieTalkieActivity.this)
系统给我们的主题是：
TypedValue outValue = new TypedValue(); context.getTheme().resolveAttribute(com.android.internal.R.attr.alertDialogTheme, outValue, true); return outValue.resourceId;
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下面分别来测试一下这几个主题
主题为：AlertDialog.THEME_HOLO_LIGHT
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this,AlertDialog.THEME_HOLO_LIGHT)
主题为：AlertDialog.THEME_TRADITIONAL
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this,AlertDialog.THEME_TRADITIONAL)
主题为：AlertDialog.THEME_DEVICE_DEFAULT_DARK
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this,AlertDialog.THEME_DEVICE_DEFAULT_DARK)
主题为：AlertDialog.THEME_DEVICE_DEFAULT_LIGHT
AlertDialog commedialog = new AlertDialog.Builder( WalkieTalkieActivity.this,AlertDialog.THEME_DEVICE_DEFAULT_LIGHT)
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作者：欧阳鹏 欢迎转载，与人分享是进步的源泉！
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