如何在我的 MainActivity 中获取 EditTextPreference 的引用？

Question

我正在尝试从我的 edittextpreference 中获取值并更改我的 mainActivity 布局中文本视图的字体大小。请帮我解决这个 guys.I 一定是在做一些傻事 mistake.Help 将不胜感激。

MainActivity.java

public class MainActivity extends AppCompatActivity {
TextView txt;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    SharedPreferences sp= PreferenceManager.getDefaultSharedPreferences(this);
    String str=sp.getString("editTextPref","50");

    if(sp!=null)
    {
        Toast.makeText(this,"String value is "+str,Toast.LENGTH_LONG).show();
        txt=(TextView) findViewById(R.id.textView);
        txt.setTextSize(Float.parseFloat(str));
    }
    Toast.makeText(this,"String value is :"+str,Toast.LENGTH_LONG).show();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main,menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int items=item.getItemId();

    switch(items)
    {
        case R.id.setting:
            Toast.makeText(this,"Settings Clicked",Toast.LENGTH_LONG).show();
            finish();
            Intent i=new Intent(this,Prefs.class);
           startActivity(i);
            break;
    }
    return super.onOptionsItemSelected(item);
}
}

Prefs.java

public class Prefs extends PreferenceActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
SharedPreferences sp;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.prefs);

    // show the current value in the settings screen
    for (int i = 0; i < getPreferenceScreen().getPreferenceCount(); i++)     {
        initSummary(getPreferenceScreen().getPreference(i));
    }
}

@Override
protected void onPause() {
    super.onPause();
     getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);
}

@Override
protected void onResume() {
    super.onResume();
    getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
}

@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
    updatePreference(findPreference(key));
}

private void initSummary(Preference p) {
    if (p instanceof PreferenceCategory) {
        PreferenceCategory cat = (PreferenceCategory) p;
        for (int i = 0; i < cat.getPreferenceCount(); i++) {
            initSummary(cat.getPreference(i));
        }
    } else {
        updatePreference(p);
    }
}

private void updatePreference(Preference p)
{
    if(p instanceof EditTextPreference)
    {
        EditTextPreference editTextPreference=(EditTextPreference) p;
        p.setSummary(editTextPreference.getText());
    }
}

@Override
public void onBackPressed() {
    super.onBackPressed();
    this.finish();
    startActivity(new Intent(Prefs.this,MainActivity.class));
    Toast.makeText(this,"Pref activity finished",Toast.LENGTH_LONG).show();
}
}

Prefs.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

<PreferenceCategory
    android:enabled="false"
    android:key="settingCategory"
    android:title="Settings"
    >
</PreferenceCategory>
<EditTextPreference
    android:id="@+id/editTextPref"
    android:dialogMessage="I am Dialog Message"
    android:dialogTitle="Dialog Title"
    android:hint="e.g 25"
    android:icon="@mipmap/ic_launcher"
    android:key="fontSize"
    android:padding="5dp"
    android:selectAllOnFocus="true"
    android:singleLine="true"
    android:summary="Changes Font Size of Overall App"
    android:title="Change Font Size" />
</PreferenceScreen>

Answer 1

您应该读取键 fontSize 的值，而不是 EditTextPreference 的 ID 字段的名称。像这样更改 MainActivity 中的代码：

SharedPreferences sp= PreferenceManager.getDefaultSharedPreferences(this);
String str=sp.getString("fontSize","50");

如何在我的 MainActivity 中获取 EditTextPreference 的引用？

How To Get Reference of EditTextPreference in my MainActivity?

java

android

android-preferences

sharedpreferences

edittextpreference