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标题图
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 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
private ListView listView;
private List> dataList;
private SimpleAdapter simple_adapter;
//1.
dataList = new ArrayList<>();
dataList=getData();
private List> getData(){
for(int i = 0;i<10;i++){
Map 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 = 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 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> dataList;
private SimpleAdapter simpleAdapter;
private void getData(){
for(int i=0;i<##;i++){
Map 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
...
android:max="100"
android:progress="40"
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
//
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 = 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
//android:entries="@array/list"
- 1
- 2
public class MainActivity extends AppCompatActivity{
private Spinner mSpinner;
...
//
final String[] arrays = getResources().getStringArray(R.array.list);
//
ArrayAdapter mSpinnerAdaper=new ArrayAdapter(MainActivity.this,android.R.layout.simple_spinner_item,arrays);
mSpinner.setAdapter(mSpinnerAdaper);
//setOnItemSelectedListener()
...
}
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