【Android】ContentProvider和ContentResolver

ref:
ContentProvider與ContentResolver
Android 原始碼徹底研究系列 - 鬧鐘程式, ContentProvider (5)

【Android】MIME Type

ref:
http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2013/0625/1386.html
http://my.oschina.net/zhangqingcai/blog/50656
http://jacky-google-android.blogspot.tw/2010/11/content-provider.html

【Android】Service概念

ref:
Android Service-概念(一)
service和Activity互動方式 (20160531 新增)

【Android】SparseBooleanArray 應用

ref:
checkboxes using SparseBooleanArray-StackOverflow
SparseArray淺析

【Android】Material Design Example

ref:
http://wannadoitnow.blogspot.tw/2015/10/android-recyclerview-swiperefreshlayout.html
http://llzz.me/2015/09/29/Android-Support-Design-Library-CoordinatorLayout/
http://blog.csdn.net/zhangphil/article/details/48877721
http://www.jianshu.com/p/533f5ecee306

【Android】實作RecyclerView + ToolBar + SearchView

ref:
http://developer.android.com/intl/zh-tw/training/material/lists-cards.html
http://stackoverflow.com/a/30429439
http://blog.30sparks.com/material-design-4-recyclerview/ (2016/01/01 新增)

Gradle:

compile 'com.android.support:appcompat-v7:23.3.0'
compile 'com.android.support:design:23.3.0'
compile 'com.android.support:recyclerview-v7:23.1.0'

res/menu:

在ToolBar新增一個搜尋圖案的按鈕

<item
        android:id="@+id/search"
        android:icon="@drawable/ic_search_black_24dp"
        android:title="Search"
        app:actionViewClass="android.support.v7.widget.SearchView"
        app:showAsAction="collapseActionView|ifRoom" />

res/layout:

RecyclerView

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

    <android.support.v7.widget.RecyclerView
        android:id="@+id/my_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"/>

</FrameLayout>

MainLayout:
content_main指的就是recyclerview

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.searchview.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay"/>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main"/>

    <!--<include layout="@layout/FAB/">-->

</android.support.design.widget.CoordinatorLayout>

MainActivity:

onCreate

//Toolbar
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //預設資料
        availableLocales = new ArrayList<>();
        for (Locale l : Locale.getAvailableLocales()) {
            availableLocales.add(l.getDisplayName());

        }

        //RecyclerView
        mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
        mRecyclerView.setHasFixedSize(true);

        //線性布局
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));


        mAdapter = new LanguageAdapter(availableLocales);
        mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());

RecyclerView布局Manager有三種：

1. 線性佈局：mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
2. 格狀佈局：mRecyclerView.setLayoutManager(new GridLayoutManager(this,4));
3. 瀑布佈局(縱向或橫向)：mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(3, OrientationHelper.VERTICAL));  //HORIZONTAL

• 設定view為預設動畫：mRecyclerView.setItemAnimator(new DefaultItemAnimator()); 
• 在adapter使用以下函數，再搭配handler postdelay，可有動畫產生。

• notifyItemChanged(int)
  notifyItemInserted(int) 
  notifyItemRemoved(int)
  notifyItemMoved(int, int)
  notifyItemRangeChanged(int, int)
  notifyItemRangeInserted(int, int)
  notifyItemRangeRemoved(int, int)
  

• int為position位址

Adapter & ViewHolder:

private class LanguageAdapter extends RecyclerView.Adapter<ViewHolder> {

        private List<String> mLocales;

        private LanguageAdapter(List<String> mLocales) {
            this.mLocales = mLocales;
            notifyDataSetChanged();
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            TextView tv = (TextView) LayoutInflater.from(parent.getContext())
                    .inflate(android.R.layout.simple_list_item_1, parent, false);

            return new ViewHolder(tv);
        }

        @Override
        public void onBindViewHolder(ViewHolder holder, int position) {
            holder.mTextView.setText(mLocales.get(position));
        }

        @Override
        public int getItemCount() {
            return mLocales.size();
        }

    }

    private static class ViewHolder extends RecyclerView.ViewHolder {

        public TextView mTextView;

        public ViewHolder(TextView v) {
            super(v);
            mTextView = v;
        }
    }

Menu

onCreateOptionsMenu
設定當Search按鈕觸發後的動作，在這裡設定當，搜尋列輸入文字時，立刻判斷預設資料是否包含收尋文字，並透過adapter作即時更新→notifyDatachanged()。

getMenuInflater().inflate(R.menu.menu_main, menu);

        final SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                mRecyclerView.setAdapter(new LanguageAdapter(OnFilter(availableLocales, newText)));
                return true;
            }
        });
        return true;

判斷輸入文字method，回傳List形態結果

//判斷輸入文字
    private List<String> OnFilter(List<String> filterLocales, String text) {
        String search = text.toLowerCase();

        final List<String> filtered = new ArrayList<>();

        for (String info : filterLocales) {
            final String localeName = info.toLowerCase();
            if (localeName.contains(search)) {
                filtered.add(localeName);
            }
        }
        return filtered;
    }

結果示意圖

【Design Pattern】

ref:深入淺出設計模式 - Google 圖書

策略模式
定義了演算法家族，個別封裝起來，讓他們之間可以互相替換，此模式讓演算法的變動，不會影響到使用演算法的程式。

設計守則

1. 找出程式中可能需要更動之處，把它們獨立出來，不要和那些不需要更動的程式碼混在一起。
   換句話說：
   把會變動的部份取出並封裝起來，以便以後可以輕易地擴充此部分，而不影響不需要更動的其他部分。
2. 寫程式是針對介面而寫，而不是針對實踐方式而寫。
3. 多用合成，少用繼承。

觀察者模式

定義了物件之間的一對多關係，如此一來，當一個物件改變狀態，其他相依者都會收到通知並自動更新。

1. 設計時，盡量讓需要互動的元件之間關係鬆綁。

【Android】SnackBar

ref:
http://stackoverflow.com/questions/30569705/android-snackbar-nullpointerexception-in-fragment
http://williammora.com/snackbar-android-library/

【Android】How to create a common class for alertDialog Box

ref:http://stackoverflow.com/a/8585364

Create a class like CustomDialog.class,

and inside of it create a static method like the one below,

 public static void ExitAppDialog(final Activity activity)
 {
     AlertDialog.Builder alertbox = new AlertDialog.Builder(activity);
     alertbox.setTitle("Warning");
     alertbox.setMessage("Exit Application?");
     alertbox.setPositiveButton("Yes", new
     DialogInterface.OnClickListener() {
     public void onClick(DialogInterface arg0, int arg1) {
         activity.finish();
     }
     });
     alertbox.setNegativeButton("No", new
     DialogInterface.OnClickListener() {
     public void onClick(DialogInterface arg0, int arg1) {

     }
     });
     alertbox.show();
 }

And in your activity's onBackPressed() call this method like this,

public void onBackPressed()
{
    CustomDialog.ExitAppDialog(myActivity.this );
}

【Android】java.lang.IllegalStateException: Fragment not attached to Activity

ref:
http://stackoverflow.com/a/22544283

Generally you get that error when you try to perform work after the Fragment is no longer attached to the Activity. In the callback that triggers the IllegalStateException add a check for isAdded:http://developer.android.com/reference/android/app/Fragment.html#isAdded()

if(!isAdded()) {
    return;
}

http://stackoverflow.com/a/10941410

I've found the very simple answer: isAdded():

Return true if the fragment is currently added to its activity.

@Override
protected void onPostExecute(Void result){
    if(isAdded()){
        getResources().getString(R.string.app_name);
    }
}

To avoid onPostExecute from being called when the Fragment is not attached to the Activity is to cancel the AsyncTask when pausing or stopping the Fragment. Then isAdded() would not be necessary anymore.