Android官方文档阅读记录

用法:1、列举已阅读的section, artice, class, lesson等标题。2、检索

Common Layouts

LinearLayout会自动创建scroll bar。

Building Layouts with an Adapter

ArrayAdapter 用法
//1、准备数据,创建 Adpater
String[] myStringArray = getMyStringArray();
ArrayAdapter adapter = new ArrayAdapter<String>(this, 
        android.R.layout.simple_list_item_1, myStringArray);

//2、(可选)
/*ArrayAdapterm默认创建TextView,显示字符串。要显示别的东西,例如image, bool,需子类化ArrayAdapter,重定义 ArrayAdapter.getView()*/

//3、绑定adpater和AdapterView
ListView listView = (ListView) findViewById(R.id.listview);
listView.setAdapter(adapter);

SimpleCursorAdapter 用法
//1、得到Cursor(也可先不获取cursor,用null,等到数据异步加载完成后再,再用changeCursor()设置cursor)
Cursor cursor = db.query(...);
String[] columns = {"name", "phone"};

String[] fromColumns = {ContactsContract.Data.DISPLAY_NAME, 
                        ContactsContract.CommonDataKinds.Phone.NUMBER};
int[] toViews = {R.id.display_name,
                 R.id.phone_number};
//2、创建Adapter
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, 
        R.layout.person_name_and_number, cursor, fromColumns, toViews, 0);
//3、ViewBinder(可选)若有SimpleCursorAdapter不支持的View,可创建
//    SimpleCursorAdapter.ViewBinder,负责将Cursor中的column,绑定到该view。
//    binder也可以改变SimpleCursorAdapter默认绑定方式。
SimpleCursorAdapter.ViewBinder binder = new SimpleCursorAdapter.ViewBinder() {
    public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
        /*返回false,表示这里没有处理,还是用默认的方式。返回true,表示使用这里的方式*/
        String columnName = cursor.getColumnName(columnIndex);
        if(columnName.equals("something")) {
            SomeView sv = (SomeView)view;
            //get data from cursor, and deliver to view
            return true;
        }
    return false;
}};
adapter.setViewBinder(binder);
//4、setAdapter: 绑定到ListView
ListView listView = getListView();listView.setAdapter(adapter);
//数据改变后,调用ArrayAdapter.notifyDataSetChanged(),刷新数据显示。
// Create a message handling object as an anonymous class.
private OnItemClickListener mMessageClickedHandler = new OnItemClickListener() {
    public void onItemClick(AdapterView parent, View v, int position, long id) {
        // Do something in response to the click }
    };
listView.setOnItemClickListener(mMessageClickedHandler);
//5、(此处代码在其他位置)
ListView lv = getListView();
lv.changeCursor(cursor);    //旧的cursor会被关闭
 

Accessing Resources


Loaders

基本功能:异步加载数据、数据更新后自动重新查询、configuration change之后,自动重新连接cursor。

Dialogs

Dialog是基类一般不用,选用: 1、AlertDialog   2、DialogFragment

DialogFragment更好。不要用Progress Dialog (用 ProgressBar)

要使用fragment来管理dialog,需要确保activity是继承自 FragmentActivity(Android 3.0以下版本,高于3.0的还是用标准Activity类)

Creating a Dialog Fragment

用法:1、继承DialogFragment 2、定义 onCreateDialog() [根据需要定义其他callback]  3、新建dialog fragment, 调用 show()

public class FireMissilesDialogFragment extends DialogFragment {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage(R.string.dialog_fire_missiles)
               .setPositiveButton(R.string.fire, new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       // FIRE ZE MISSILES!
                   }
               })
               .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       // User cancelled the dialog
                   }
               });
        // Create the AlertDialog object and return it
        return builder.create();
    }
}


Building an Alert Dialog

AlertDialog分为三个区域:1、title(content area很小时常常不用) 2、content area 3、button bar(3 buttons at most)

用AlertDialog.Builder来创建dialog:1、new AlertDialog.Builder()   2、builder.setXXX()   3、AlertDialog dialog = builder.create()

// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// 2. Chain together various setter methods to set the dialog characteristics
builder.setMessage(R.string.dialog_message)
       .setTitle(R.string.dialog_title);
// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();
Building an Alert Dialog -> Adding Buttons    按钮类型:Positive、Negative、Neutral

AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
               // User clicked OK button
           }
       });
builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
               // User cancelled the dialog
           }
       });
// Set other dialog properties
...

AlertDialog dialog = builder.create();

Builing an Alert Dialog -> Adding a list    类型:单选list、持久单选list(radiobutton)、持久多选list(checkbox)——持久的意思:点击一个item,对话框不会关闭

setItems(), setSingleChoiceItems(), setMultiChoiceItems()

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setTitle(R.string.pick_color);
           .setItems(R.array.colors_array, new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int which) {
               // The 'which' argument contains the index position
               // of the selected item
           }
    });
注:设置list除了setItems() 也可用 setAdapter()

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    mSelectedItems = new ArrayList();  // Where we track the selected items
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setTitle(R.string.pick_toppings)
    // Specify the list array, the items to be selected by default (null for none),
    // and the listener through which to receive callbacks when items are selected
           .setMultiChoiceItems(R.array.toppings, null,
                      new DialogInterface.OnMultiChoiceClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int which,
                       boolean isChecked) {
                   if (isChecked) {
                       mSelectedItems.add(which);
                   } else if (mSelectedItems.contains(which)) {
                       mSelectedItems.remove(Integer.valueOf(which));
                   }
               }
           })
           .setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int id) {
                   // User clicked OK, so save the mSelectedItems results somewhere
                   // or return them to the component that opened the dialog
                   ...
               }
           })
           .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int id) {
                   ...
               }
           });

    return builder.create();
}

Creating a Custom Layout

步骤:按照以上AlertDialog.Builder用法, 将setItems() 改为setView() 设置custom layout。

该layout只占用content area,不占用title, button bar。

一般需要用LayoutInflater,加载layout

public Dialog onCreateDialog(Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

    LayoutInflater inflater = getActivity().getLayoutInflater();

    // Inflate and set the layout for the dialog
    // Pass null as the parent view because it is going in the dialog layout
    builder.setView(inflater.inflate(R.layout.dialog_signin, null))
           .setPositiveButton(R.string.signin, new DialogInterface.OnClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int id) {
                   // sign in the user ...
               }
           })
           .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int id) {
                   LoginDialogFragment.this.getDialog().cancel();
               }
           });      
    return builder.create();
}

Passing Events Back to the Dialog's Host

方法:1、在DialogFragment中,设计一个interface,定义callback  2、host 实现这个接口及callback

3、创建DialogFragment时,想办法让dialog得到host引用(例如,通过Fragment.onAttach()  或 getActivity())。

4、点击事件的代码通过接口访问host component,把对象传过去

注:其实就是让dialog引用创建它的host(跟以前的做法一样),因为使用了interface,比较灵活。

注:没有特别的API,属编码设计技巧,看原文。

Showing a Dialog

方法:1. new DialogFragment   -> 2.show()

提示:可以通过 FragmentActivity.getSupportedFragmentManager()  or Fragment.getFragmentManager() 获得 FragmentManager

调用show()之后,这个fragment 其实被 FragmentManager管理起来了(会被自动删除)。不考虑复用以前的fragment。

public void confirmFireMissiles() {
    DialogFragment newFragment = new FireMissilesDialogFragment();
    newFragment.show(getSupportFragmentManager(), "missiles");
}
Showing a Dialog Fullscreen or as an embeded Fragment

让一部分UI既作为dialog,又作为 fullscreen / embeded fragment

//TODO

原文链接

Showing an activity as a dialog on large screens

(正好与上面相反)  把activity作为dialog,只需把activity的theme设为 Theme.Holo.DialogWhenLarge 或者Theme.Holo.Dialog,不用写代码。

Theme.Holo.DialogWhenLarge  只有在屏幕大的设备上运行时,activity作为dialog显示。

Theme.Holo.Dialog  一律将activity作为dialog。

<activity android:theme="@android:style/Theme.Holo.DialogWhenLarge" >

Dismissing a Dialog

涉及DialogFragment的几个函数: dismiss()   onDismiss()   cancel()   onCancel()


Pickers

picker就是下面选时间和日期的widget

Creating a Time Picker

跟Dialogs文档中创建对话框的方法完全一样,要求:

1、在onCreateDialog()中返回 DatePickDialog / TimePickerDialog。

2、host实现一个TimePickerDialog.OnTimeSetListener 接口,响应dialog完成时的callback。

原文链接(注:演示代码是fragment自己实现那个接口的,这个意义不大,要像Dialogs中的那样,让host实现这个接口。fragment通过onAttach()获得host)

Creating a Date Picker

同上


(1、概述、解释、介绍、原理、工作机制等内容一概省略。2、用法、注意事项。3、来源:Android Developers)

备注:csdn编辑器不使用复制粘贴,格式很容易混乱,经常自动插入一些tag。

为什么英文难理解,个人分析得出的原因:

1、过度追求准确,强调语法:第一、三人称。。。。 单数复数。。。时态。。。。

2、主次不清,重要信息常位于句子后半部。。。常把重要信息作为定语从句,前半句显得毫无意义没多少信息。

3、常常动词名词不分,动词常常直接作为名词,表示抽象的概念。

4、习语、短语多,从字面上无法直接理解涵义,这些短语的真正含义与单词本身含义相差甚远。

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