APIDEMO PREFERENCE 学习 ACTIVTIY

最新推荐文章于 2025-08-22 06:26:24 发布

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最新推荐文章于 2025-08-22 06:26:24 发布

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分类专栏： Android知识点文章标签： android attributes list layout processing permissions

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本文深入解析了Android中Preference的应用方式，包括XML配置方法与代码实现细节，并展示了如何自定义Preference控件及其在Activity中的实际应用。

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Prefercence 观察来看设计思想应该是简化设置的UI的界面布局所用。

主题是 PreFerenceActivity

1：xml

Code实现：

private PreferenceScreen createPreferenceHierarchy() { // Root PreferenceScreen root = getPreferenceManager().createPreferenceScreen(this); // Inline preferences PreferenceCategory inlinePrefCat = new PreferenceCategory(this); inlinePrefCat.setTitle(R.string.inline_preferences); root.addPreference(inlinePrefCat); // Toggle preference CheckBoxPreference togglePref = new CheckBoxPreference(this); togglePref.setKey("toggle_preference"); togglePref.setTitle(R.string.title_toggle_preference); togglePref.setSummary(R.string.summary_toggle_preference); inlinePrefCat.addPreference(togglePref); // Dialog based preferences PreferenceCategory dialogBasedPrefCat = new PreferenceCategory(this); dialogBasedPrefCat.setTitle(R.string.dialog_based_preferences); root.addPreference(dialogBasedPrefCat); // Edit text preference EditTextPreference editTextPref = new EditTextPreference(this); editTextPref.setDialogTitle(R.string.dialog_title_edittext_preference); editTextPref.setKey("edittext_preference"); editTextPref.setTitle(R.string.title_edittext_preference); editTextPref.setSummary(R.string.summary_edittext_preference); dialogBasedPrefCat.addPreference(editTextPref); // List preference ListPreference listPref = new ListPreference(this); listPref.setEntries(R.array.entries_list_preference); listPref.setEntryValues(R.array.entryvalues_list_preference); listPref.setDialogTitle(R.string.dialog_title_list_preference); listPref.setKey("list_preference"); listPref.setTitle(R.string.title_list_preference); listPref.setSummary(R.string.summary_list_preference); dialogBasedPrefCat.addPreference(listPref); // Launch preferences PreferenceCategory launchPrefCat = new PreferenceCategory(this); launchPrefCat.setTitle(R.string.launch_preferences); root.addPreference(launchPrefCat); /* * The Preferences screenPref serves as a screen break (similar to page * break in word processing). Like for other preference types, we assign * a key here so that it is able to save and restore its instance state. */ // Screen preference PreferenceScreen screenPref = getPreferenceManager().createPreferenceScreen(this); screenPref.setKey("screen_preference"); screenPref.setTitle(R.string.title_screen_preference); screenPref.setSummary(R.string.summary_screen_preference); launchPrefCat.addPreference(screenPref); /* * You can add more preferences to screenPref that will be shown on the * next screen. */ // Example of next screen toggle preference CheckBoxPreference nextScreenCheckBoxPref = new CheckBoxPreference(this); nextScreenCheckBoxPref.setKey("next_screen_toggle_preference"); nextScreenCheckBoxPref.setTitle(R.string.title_next_screen_toggle_preference); nextScreenCheckBoxPref.setSummary(R.string.summary_next_screen_toggle_preference); screenPref.addPreference(nextScreenCheckBoxPref); // Intent preference PreferenceScreen intentPref = getPreferenceManager().createPreferenceScreen(this); intentPref.setIntent(new Intent().setAction(Intent.ACTION_VIEW) .setData(Uri.parse("http://www.android.com"))); intentPref.setTitle(R.string.title_intent_preference); intentPref.setSummary(R.string.summary_intent_preference); launchPrefCat.addPreference(intentPref); // Preference attributes PreferenceCategory prefAttrsCat = new PreferenceCategory(this); prefAttrsCat.setTitle(R.string.preference_attributes); root.addPreference(prefAttrsCat); // Visual parent toggle preference CheckBoxPreference parentCheckBoxPref = new CheckBoxPreference(this); parentCheckBoxPref.setTitle(R.string.title_parent_preference); parentCheckBoxPref.setSummary(R.string.summary_parent_preference); parentCheckBoxPref.setKey("test"); prefAttrsCat.addPreference(parentCheckBoxPref); // Visual child toggle preference // See res/values/attrs.xml for the <declare-styleable> that defines // TogglePrefAttrs. //代码有个问题就是父子的依赖处理没有实现，如何实现本人 //用setDependent()没有测试出来，xml的依赖是对的。 TypedArray a = obtainStyledAttributes(R.styleable.TogglePrefAttrs); CheckBoxPreference childCheckBoxPref = new CheckBoxPreference(this); childCheckBoxPref.setTitle(R.string.title_child_preference); childCheckBoxPref.setSummary(R.string.summary_child_preference); childCheckBoxPref.setDisableDependentsState(true); childCheckBoxPref.setLayoutResource( a.getResourceId(R.styleable.TogglePrefAttrs_android_preferenceLayoutChild, 0)); prefAttrsCat.addPreference(childCheckBoxPref); a.recycle(); return root;

亦可以自定义PreFerecnce控件 MyPreference

public class MyPreference extends Preference { private int mClickCounter; // This is the constructor called by the inflater public MyPreference(Context context, AttributeSet attrs) { super(context, attrs); setWidgetLayoutResource(R.layout.preference_widget_mypreference); } @Override protected void onBindView(View view) { super.onBindView(view); // Set our custom views inside the layout final TextView myTextView = (TextView) view.findViewById(R.id.mypreference_widget); if (myTextView != null) { myTextView.setText(String.valueOf(mClickCounter)); } } @Override protected void onClick() { int newValue = mClickCounter + 1; // Give the client a chance to ignore this change if they deem it // invalid if (!callChangeListener(newValue)) { // They don't want the value to be set return; } // Increment counter mClickCounter = newValue; // Save to persistent storage (this method will make sure this // preference should be persistent, along with other useful checks) persistInt(mClickCounter); // Data has changed, notify so UI can be refreshed! notifyChanged(); } @Override protected Object onGetDefaultValue(TypedArray a, int index) { // This preference type's value type is Integer, so we read the default // value from the attributes as an Integer. return a.getInteger(index, 0); } @Override protected void onSetInitialValue(boolean restoreValue, Object defaultValue) { if (restoreValue) { // Restore state mClickCounter = getPersistedInt(mClickCounter); } else { // Set state int value = (Integer) defaultValue; mClickCounter = value; persistInt(value); } } @Override protected Parcelable onSaveInstanceState() { /* * Suppose a client uses this preference type without persisting. We * must save the instance state so it is able to, for example, survive * orientation changes. */ final Parcelable superState = super.onSaveInstanceState(); if (isPersistent()) { // No need to save instance state since it's persistent return superState; } // Save the instance state final SavedState myState = new SavedState(superState); myState.clickCounter = mClickCounter; return myState; } @Override protected void onRestoreInstanceState(Parcelable state) { if (!state.getClass().equals(SavedState.class)) { // Didn't save state for us in onSaveInstanceState super.onRestoreInstanceState(state); return; } // Restore the instance state SavedState myState = (SavedState) state; super.onRestoreInstanceState(myState.getSuperState()); mClickCounter = myState.clickCounter; notifyChanged(); } /** * SavedState, a subclass of {@link BaseSavedState}, will store the state * of MyPreference, a subclass of Preference. * <p> * It is important to always call through to super methods. */ private static class SavedState extends BaseSavedState { int clickCounter; public SavedState(Parcel source) { super(source); // Restore the click counter clickCounter = source.readInt(); } @Override public void writeToParcel(Parcel dest, int flags) { super.writeToParcel(dest, flags); // Save the click counter dest.writeInt(clickCounter); } public SavedState(Parcelable superState) { super(superState); } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState createFromParcel(Parcel in) { return new SavedState(in); } public SavedState[] newArray(int size) { return new SavedState[size]; } }; } }

<?xml version="1.0" encoding="utf-8"?>   <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/mypreference_widget" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:layout_marginRight="6sp" android:focusable="false" android:clickable="false" />

使用：

public class AdvancedPreferences extends PreferenceActivity implements OnSharedPreferenceChangeListener { public static final String KEY_MY_PREFERENCE = "my_preference"; public static final String KEY_ADVANCED_CHECKBOX_PREFERENCE = "advanced_checkbox_preference"; private CheckBoxPreference mCheckBoxPreference; private Handler mHandler = new Handler(); /** * This is a simple example of controlling a preference from code. */ private Runnable mForceCheckBoxRunnable = new Runnable() { public void run() { if (mCheckBoxPreference != null) { mCheckBoxPreference.setChecked(!mCheckBoxPreference.isChecked()); } // Force toggle again in a second mHandler.postDelayed(this, 1000); } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Load the XML preferences file addPreferencesFromResource(R.xml.advanced_preferences); // Get a reference to the checkbox preference mCheckBoxPreference = (CheckBoxPreference)getPreferenceScreen().findPreference( KEY_ADVANCED_CHECKBOX_PREFERENCE); } @Override protected void onResume() { super.onResume(); // Start the force toggle mForceCheckBoxRunnable.run(); // Set up a listener whenever a key changes getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this); } @Override protected void onPause() { super.onPause(); // Unregister the listener whenever a key changes getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this); mHandler.removeCallbacks(mForceCheckBoxRunnable); } public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) { // Let's do something when my counter preference value changes if (key.equals(KEY_MY_PREFERENCE)) { Toast.makeText(this, "Thanks! You increased my count to " + sharedPreferences.getInt(key, 0), Toast.LENGTH_SHORT).show(); } } }

可以在Activity 主UI 线程中使用preference xml 的值

1：先在主ＵＩ中定义

/*
         * If this were my app's main activity, I would load the default values
         * so they're set even if the user does not go into the preferences
         * screen. Another good place to call this method would be from a
         * subclass of Application, so your default values would be loaded
         * regardless of entry into your application (for example, a service or
         * activity).
         */
        PreferenceManager.setDefaultValues(this, R.xml.advanced_preferences, false);

２：　使用

SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
final int counter = sharedPref.getInt(AdvancedPreferences.KEY_MY_PREFERENCE, 0);