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在Android中我们常常用到很多UI控件，如TextView，EditText，ImageView，Button，ImageButton，ToggleButton，CheckBox，RadioButton等等这些可以自己多用就会了。

也会学到一些布局如：LinearLayout 线性布局，RelativeLayout 相对布局，FrameLayout 帧布局，AbsoluteLayout绝对布局，TableLayout 表格布局，GridLayout 网格布局，ConstraintLayout 约束布局。

LinearLayout 线性布局:

android:orientation="vertical"
android:orientation="horizontal"

RelativeLayout 相对布局：

android:layout_alignParentTop
android:layout_alignParentBottom
android:layout_alignParentLeft
android:layout_alignParentRight

android:layout_marginTop
android:layout_marginBottom
android:layout_marginLeft
android:layout_marginRight
android:layout_margin

android:layout_centerVertical
android:layout_centerHorizontal
android:layout_centerInParent

android:layout_above
android:layout_below
android:layout_alignLeft
android:layout_alignRight
android:layout_toLeftOf
android:layout_toRightOf
android:layout_alignBottom
android:layout_alignTop
android:layout_alignBaseline

TableLayout 表格布局：

android:layout_span
android:layout_column
android:collapseColumns
android:shrinkColumns
android:stretchColumns

属性

android:id
android:layout_width
android:match_parent
android:text
android:background
android:textSize
android:textColor
android:inputType
android:hint

结构：

AndroidManifest.xml为整个应用的主配置，清单文件，应用的包名、版本号、组件、权限等信息。

Activity的活动状态：

activity is running：为活动状态
onResume()->running->onPause()：为暂停状态
onStart()->onResume()->running->onPause()->onStop()：为停止状态
onDestroy()：为非活动状态

onCreate()
onStart()
onResume()
onPause()
onStop()
onDestroy()
onRestart()

跳转：第二个界面：

private Button mButton;
private String text="dashu";

mButton.setOnClickListener(new View.OnClickListener(){
 @Override
 public void onClick(View v){
  Intent data = new Intent();
  data.putExtra("text",text);
  setResult(2,data);
  finish();
 }
}

跳转：第一个界面：

@Override
protected void onActivityResult(int requestCode,int resuleCode,Intent data){
 super.onActivityResult(requestCode,resultCode,data):
   if(requestCode==1&&resultCode==2){
      String text = data.getStringExtra("text");
      textView.setTextView(text);
    }
}

ListView与ArrayAdapter的搭配：

//准备数据源->适配器加载数据源->控件加载适配器
public class MainActivity extends AppCompatActivity{
 private ListView listView;
 private ArrayAdapter<String> list_adpater;

 @Override
 protected void onCreate(Bundle savedInsstanceState){
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  listView=findViewById(R.id.listView);
  
  //1
 String data[] = {"dashu1","dashu2","dashu3"};
 //2
  list_adpater = new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,data);
 //3
  listView.setAdapter(list_adapter);
  
 }
}

ListView与SimpleAdapter的搭配：

//列表项
//布局
<ListView
 android:id="@android:id/app_list"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"/>
//单个列表项
<ImageView
        android:id="@+id/icon_image_view"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@mipmap/ic_launcher"/>
<TextView
        android:id="@+id/title_text_view"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:text="@string/app_name"
        android:textSize="24sp"/>

private ListView listView;
private List<Map<String,Object>> dataList;
private SimpleAdapter simple_adapter;
//1.
dataList = new ArrayList<>();
dataList=getData();
private List<Map<String,Object>> getData(){
 for(int i = 0;i<10;i++){
   Map<String,Object> map = new HashMap<>();
   map.put("image",R.drawable.images1);
   map.put("text",i);
   dataList.add(map);
 }
  return dataList;
}
//2.
simple_adapter = new SimpleAdapter(this,dataList,R.layout.item,new String[]{"image","text"},new int[]{"R.id.imageView","R.id.imageView"});
//3.
listView.setAdapter(simple_adapter);

To:

public class App{
 private String appName;
 private int appId;
  App(String appName,int appId){
 }
}
//
public class AppAdapter extentds ArrayAdapter<App>{
    ...
     App app = getItem(position);
     View view = LayoutInflater.from(getContext()).inflate(...);
}
//
 //获取视图
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        //创建ViewHolder
        ViewHolder viewHolder = null;
        //如果为空
        if (convertView == null){
         //mInflater.inflate(渲染布局，parent , false)
         convertView = mInflater.inflate(R.layout.item_msg,parent,false);
         viewHolder = new ViewHolder();//创建类对象
         //视图
         viewHolder.mIvImg = convertView.findViewById(R.id.id_iv_img);
         viewHolder.mTvTitle = convertView.findViewById(R.id.id_tv_title);
         viewHolder.mTvContent = convertView.findViewById(R.id.id_tv_content);

         convertView.setTag(viewHolder);// convertView.getTag();

        }else {
            viewHolder = (ViewHolder) convertView.getTag();// convertView.getTag();
        }
        //获取数据位置
        Message msg = mDatas.get(position);//数据集合 private List<Message> mDatas;
        viewHolder.mIvImg.setImageResource(msg.getImgResId());//获取图片位置
        viewHolder.mTvTitle.setText(msg.getTitle());//获取标题
        viewHolder.mTvContent.setText(msg.getContent());//获取内容

        return convertView;
    }

    public static class ViewHolder{
        //静态内部类，类调用
        ImageView mIvImg;
        TextView mTvTitle;
        TextView mTvContent;
    }
//or
App app = getItem(position);
if(convertView==null){
          view=LayoutInflater.from(getContext()).inflate(resourceId, null);
          viewHolder=new ViewHolder();
          viewHolder.imageView= view.findViewById(R.id.app_image);
          viewHolder.textView= view.findViewById(R.id.appl_name);
          view.setTag(viewHolder);
    }else{
         view=convertView;
         viewHolder = (ViewHolder) view.getTag();
  ...
  return view;
}

To:

private List<Map<String,Object>> dataList;
private SimpleAdapter simpleAdapter;
private void getData(){
 for(int i=0;i<##;i++){
  Map<String,Object> map = new HashMap<>();
  map.put("",##);
  dataList.add(##);
 }
}

ProgressBar：max，progress，secondaryProgress

style="?android:attr/progressBarStyleHorizontal"
style="?android:attr/progressBarStyleLarge"
style="?android:attr/progressBarStyle"
style="?android:attr/progressBarStyleSamll"

int first=progressBar.getProgress();
int second=progressBar.getSecondaryProgress();
int max = progress.getMax();

progressBar.incrementProgressBy(5);
progressBar.incrementSecondaryProgressBy(5);

progress.incrementProgressBy(-5);
progressBar.incrementSecondaryProgressBy(-5);

ProgressDialog progressDialog = new ProgressDialog(this);
//
progressDialog.setProgresssStyle(ProgressDialog.STYLE_HORIZONTAL);
progressDialog.setTitle("");
progressDialog.setIcon("");
//
progressDialog.setMax(100);
progressDialog.incrementProgressBy(20);
//
progessDialog.setButton(DialogInterface.BUTTON_POSITIVE,"确定",new DialogInterface.OnClickListener(){
  ...
});
progressDialog.setCancelable(true);
//
progressDialog.show();

SeekBar：OnSeekBarChangeListener

<SeekBar>
  ...
  android:max="100"
  android:progress="40"
</SeekBar>

seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener(){

});

日历选择器：OnDateChangedListener

//DataPicker日历选择器
private DataPicker dataPicker;
private Calendar calendar;
private int year,day,hour,minute;
//
calendar = Calendar.getInstance();
//
year = calendar.get(Calendar.YEAR);
...
minute = calendar.get(Calendar.MINUTE);

//DataPickerDialog-OnDateSetListener()
new DatePickerDialog(this, newDatePickerDialog.OnDateSetListener(){
  ...
},year,calendar.get(Calendar.MONTH),day).show();
//TimePicker-setOnTimeChangedListener()
//TimePickerDialog-OnTimeSetListener
new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener(){
  ....
},hour,minute,true).show();

Meau：

//OptionsMenu,SubMenu,ContextMenu
//
<menu>
<item android:id="@+id/item1"
android:title="1"
</item>
<item android:id="@+id/item12"
android:title="12"
</item>
//
<item android:id="@+id/play" android:title="玩">
 <menu>
  <item android:id="" android:title="下棋"/>
  <item .../>
 </menu>
</item>
//
雷同SubMenu
//
getMenuInflater().inflate();
onCreateOptionsMenu();
onCreateContextMenu();
//动态
onCreateOptionsMenu(Menu menu){
 menu.add(1,1,1,"1");
 menu.add(1,2,1,"2");
  return super.onCreateOptionsMenu(menu);
}
onCreateContextMenu(ContextMenu menu,View v,ContextMenu.ContextMenuInfo menuInfo){
 //menu.setHeaderTitle();
 //menu.setHeaderIcon();
 menu.add(1,1,1,"1");
 menu.add(1,2,1,"2");
  ...
  super.onCreateContextMenu(menu,v,menuInfo);
}
//
onCreateOptionsMenu(Menu menu){
 //SubMenu play=menu.addSubMenu();
 play.setHeaderTitle();
 play.setHeaderIcon();
 play.add();
 play.add();
  SubMenu play2=menu.addSubMenu();
  paly2.add(2,1,1,"");
  play2.add(2,2,1,"");
  return super.onCreateOptionsMenu(menu);
}
//
ContextMenu
ListView = findViewById(R.id.listView);
adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,data);
listView.setAdapter(adapter);
registerForContextMenu(listView);

//OnOptionsItemSelected
OnOptionsItemSelected(MenuItem item){
 if(item.getGroupId() == 1){
  switch(item.getItemId()){
   case 1:
     break;
   case 2:
    break;
  }
 }
 ...
}

Notification 通知：

图标（SmallIcon）
标题（ContextTitle）
内容（ContextText）
时间（When）

NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
//
builder.setSmallIcon();
...
builder.setDefaults(Notification.DEFAULT_ALL);
//
PendingIntent类-setContentIntent()
NotificationManager去完成发送和取消通知的事情

Dialog 对话框：

//setPositiveButton()和setNegativeButton()：添加确定和取消按钮
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle();
...
builder.setPositiveButton("确认", new DialogInterface.OnClickListener(){
 ...
}
builder.setNegativeButton("取消", new DialogInterface.OnClickListener(){
 ...
}
Dialog dialog = builder.create();
dialog.show();
//setSingleChoiceItems()
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle();
builder.setIcon();
builder.setSingleChoiceItems(data,0,new DialogInterface.OnClickListener(){
  ...
});
Dialog dialog = builder.create();
dialog.show();

WebView：

//uri , setAction , setData
Uri uri = Uri.parse(url);
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setData(uri);
startActivity(intent);

<WebView>
</WebView>

//
webView = findViewById(R.id.webView);
webView.loadUrl(url);
//
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
//
webView.setWebViewClient(new WebViewClient(){
  ...
});

//
webView.setWebChromeClient(new WebChromeClient(){
   ...
   //
   if(dialog != null && dialog.isShowing()){
     dialog.dismiss():
     dialog = null;
   }
   ...
   //
    if(dialog == null){
      dialog = new ProgressDialog(MainActivity.this);
      dialog.setTitle();
       ...
      dialog.show();
     }else{
       dialog.setProgress(newProgress);
     }
}

Fragment：为了解决Android碎片化

Fragment is added
onAttach()
onCreate()
onCreateView()
onActivityCreated()
onStart()
onResume()
Fragement is activite
onPause()
onStop()
onDestroyView();
onDestroy()
onDetach()
Fragment is destroyed

onCreate()
onCreateView()
onActivityCreated()
onStart()
onResume()

onPause()
onStop()

onStart()
onResume()

onPause()
onStop()
onDestroyView()
onDestroy()
onDetach()

//
MyFragment fragment = new MyFragment();
FragementManager fragmentManager = getFragmentManager();
FragmentTransaction beginTransaction = fragmentManager.beginTransaction();

beginTransaction.add(R.id.layout,fragment);
beginTransaction.commit();

//
getFragmentManager().beginTransaction().add(R.id.layout,fragment).commit();

//myFragment = (MyFragment)getFragmentManager(). findFragmentById(R.id.fragment);
//Fragment.java
Toast.makeText(getActivity(),"dashu",Toast.LENGTH_SHORT).show();

File,SharedPreferences,SQLite

private SQLiteDatabase db;
public class MyHelper extends SQLiteOpenHelper{
 public static String CREATE_TABLE="create table student("
   + " _id integer primary key autoincrement,"
   + "name varchar(20),"
   + "age integer,"
   + "sex varchar(2)";
   public Context mContext;
   
  public MyHelper(Context context,String name,SQLiteDatabase.CursorFactory factory,int version){
  super(context,name,factory,version);
  mContext=context;
}
@Override
public void onCreate(SQLiteDatabase db){
 db.execSQL();
}

//
Cursor cursor=db.query("student",null,null,null,null,null,null);
if(cursor!=null){
  while(cursor.moveToNext()){
  
  }
}

ContentProvider
Android四大组件之一，为存储和获取数据提供统一的接口。
自定义类继承ContentProvider，通过android:authorities属性授权。ContentResolver内容处理者，提供ContentProvider中同名同参的增删改查方法。

boolean onCreate()
String getType(Uri uri)
Cursor query()
Uri insert()
int update()
int delete()
//URI : 完整的uri路径
//
ContentProvider内容提供者
ContentResolver内容解析者

Spinner下拉框

<RelativeLayout>
 <Spinner
   android:id="@+id/spinner" ...
</RelativeLayout>
//android:entries="@array/list"
<resources>
  <array name="list">
   <item>1</item>
   <item>2</item>
  </array>
</resources>

public class MainActivity extends AppCompatActivity{
 private Spinner mSpinner;
  ...
   //
   final String[] arrays = getResources().getStringArray(R.array.list);
  //
  ArrayAdapter<String> mSpinnerAdaper=new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_spinner_item,arrays);
    mSpinner.setAdapter(mSpinnerAdaper);
   //setOnItemSelectedListener()
   ...
}

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定位：分享 Android&Java 知识点