Android对话框从字符串显示TextView中的HTML

Question

I'm trying to show HTML code in a dialog but the HTML needs to be stored in a string which is first put into a textview.

I have found many other questions about something similar but most are setting the text in code rather than in strings.xml. None I found seem to use a 'dialog to textview to string with html' process. I've done so far what I think should work but I'm getting an error now (below). I've tried other ways but cannot get the HTML effects to show.

I'm still new to Android so any help to see what I'm doing wrong would be great. Thanks.

preferencesActivity.java - OnCreate

       Preference myPref = (Preference) findPreference("pref_showHelp");
       myPref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
                    public boolean onPreferenceClick(Preference preference) {

                        Dialog dialog = new  dialog(preferencesActivity.this);
                        helpFile_textView = (TextView) findViewById(R.id.helpFile_textView);
                        helpFile_textView.setText(Html.fromHtml(getString(R.string.helpFile_text))); // Line 44
                        dialog.setContentView(R.layout.helpfile);
                        dialog.setTitle("Help");
                        dialog.show();

                      return false;
                    }
                });
}

helpfile .xml

<TextView
    android:id="@+id/helpFile_textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:text="@string/helpFile_text" />

</LinearLayout>

Strings .xml

<string name="helpFile_text">Test of <b>bold and <u>underline</u> and bullet &#8226;</string>

Logcat

E/AndroidRuntime(1516): java.lang.NullPointerException
E/AndroidRuntime(1516):     at com.example.newcalc.preferencesActivity$1.onPreferenceClick(preferencesActivity.java:44)

Answer 1

Change

helpFile_textView = (TextView) findViewById(R.id.helpFile_textView);
helpFile_textView.setText(Html.fromHtml(getString(R.string.helpFile_text)));
dialog.setContentView(R.layout.helpfile);     

to

dialog.setContentView(R.layout.helpfile);     
helpFile_textView = (TextView) dialog.findViewById(R.id.helpFile_textView);
helpFile_textView.setText(Html.fromHtml(getString(R.string.helpFile_text)));

You have to inflate the layout that you want to use in the Dialog before you can find it using findViewById

Also since the id you want to find (ie helpFile_textView ) is in the layout that you inflated in dialog you have to use dialog.findViewById instead of findViewById to get the TextView

Also

Dialog dialog = new dialog(preferencesActivity.this);

should be

Dialog dialog = new Dialog(preferencesActivity.this);

but i think that is a typo.

Answer 2

try this

dialog.setContentView(R.layout.helpfile);    
helpFile_textView = (TextView) dialog.findViewById(R.id.helpFile_textView);    
helpFile_textView.setText(Html.fromHtml(preferencesActivity.this.getResources().getString(R.string.helpFile_text)));

for more correction refer @Aproov's answer.