Question

在AlertDialog中，我可以设置Message的大小，但是当我为Title执行相同操作时，它会崩溃。

代码：

AlertDialog dialog = new AlertDialog.Builder(this).setMessage(message).setTitle(title)
               .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                      dialog.cancel();
                   }
               }).show();
     TextView titleTxt= (TextView)dialog.findViewById(android.R.id.title);
     **titleTxt.setTextSize(TypedValue.COMPLEX_UNIT_SP, 40);** // crash here 
     TextView textView = (TextView) dialog.findViewById(android.R.id.message);
     **textView.setTextSize(40);** // works fine



 Button btn1 = dialog.getButton(DialogInterface.BUTTON_POSITIVE);
   btn1.setTextSize(36);

我的输出：

05-10 11:49:56.917: E/AndroidRuntime(8376): FATAL EXCEPTION: main
05-10 11:49:56.917: E/AndroidRuntime(8376): java.lang.NullPointerException
05-10 11:49:56.917: E/AndroidRuntime(8376):     at com.binary.taxitop.LoginScreen.showAlertDialog(LoginScreen.java:116)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at com.binary.taxitop.LoginScreen.VerifyCredentialsAndEnterNextScreen(LoginScreen.java:103)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at com.binary.taxitop.LoginScreen.onClick(LoginScreen.java:84)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at android.view.View.performClick(View.java:3511)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at android.view.View$PerformClick.run(View.java:14109)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at android.os.Handler.handleCallback(Handler.java:605)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at android.os.Looper.loop(Looper.java:137)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at android.app.ActivityThread.main(ActivityThread.java:4424)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at java.lang.reflect.Method.invokeNative(Native Method)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at java.lang.reflect.Method.invoke(Method.java:511)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-10 11:49:56.917: E/AndroidRuntime(8376):     at dalvik.system.NativeStart.main(Native Method)

提前致谢。

Answer 1

只需改变这一行：

TextView titleTxt= (TextView)dialog.findViewById(getApplicationContext().getResources().getIdentifier( "alertTitle", "id", "android" ));

Answer 2

据我所知，没有直接方法可以修改title

中的AlertDialog

您可以创建自定义对话框或使用反射

下面的反映代码来自net，希望它有用

AlertDialog dialog = (AlertDialog) getDialog();  
try {  
     Field mAlert = AlertDialog.class.getDeclaredField("mAlert");  
     mAlert.setAccessible(true);  
     Object alertController = mAlert.get(dialog);  

     Field mTitleView = alertController.getClass().getDeclaredField("mTitleView");  
     mTitleView.setAccessible(true);  

     TextView title = (TextView) mTitleView.get(alertController);  
     title.setTextColor(0xff33b5e5);   

} catch (NoSuchFieldException e) {  
    e.printStackTrace();  
} catch (IllegalArgumentException e) {  
     e.printStackTrace();  
} catch (IllegalAccessException e) {  
    e.printStackTrace();  
}

Answer 3

当我遇到像你这样的情况时，这是我的代码。

修改： -

String title = "Title"; SpannableStringBuilder Builder = new SpannableStringBuilder(title);//Your title goes here StyleSpan spanState1 = new StyleSpan(Typeface.ITALIC);//You can make your title italic ,bold etc here //ScaleXSpan spanState2 = new ScaleXSpan(4);// As far your font is concern, this will help Builder.setSpan(new RelativeSizeSpan(2.8f), 0, title.length(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);// set your size there Builder.setSpan(spanState1, 0, title.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE); //Builder.setSpan(spanState2, 0, title.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE); AlertDialog.Builder dialog_build = new AlertDialog.Builder(MainActivity.this); dialog_build.setTitle(Builder); dialog_build.show();

仅关注标题，因为这是你的关注......

希望，这有帮助

尝试在AlertDialog上设置标题大小时出现NullPointerException异常

3 个答案: