小寫轉(zhuǎn)大寫 ： ctrl+shift+F

<ScrollView></ScrollView>滾動條顯示視圖

ListView與BaseAdapter：

1 public class MainActivity extends Activity { 2 private List<Person> pList; 3 @Override 4 protected void onCreate(Bundle savedInstanceState) { 5 super.onCreate(savedInstanceState); 6 setContentView(R.layout.activity_main); 7 8 ListView mlistview=(ListView)findViewById(R.id.listview); 9 //把view與適配器關(guān)聯(lián) 10 mlistview.setAdapter(new MyAdapter()); 11 } 12 13 class MyAdapter extends BaseAdapter{ 14 15 //獲取view數(shù)據(jù)的長度 16 @Override 17 public int getCount() { 18 return pList.size(); 19 } 20 21 @Override 22 public Object getItem(int position) { 23 // TODO Auto-generated method stub 24 return null; 25 } 26 27 @Override 28 public long getItemId(int position) { 29 // TODO Auto-generated method stub 30 return 0; 31 } 32 33 //獲得ListView中的某一行的view對象 34 //postion返回當前索引的位置 35 //convertView 緩存對象 36 //parent是listView對象 37 @Override 38 public View getView(int position, View convertView, ViewGroup parent) { 39 TextView tv=null; 40 if(convertView!=null){//判斷緩存對象是否為空 41 tv=(TextView)convertView; 42 }else{//等于null程序剛加載，則創(chuàng)建 43 tv=new TextView(MainActivity.this);//類名.this ==上下文 44 } 45 Person p=pList.get(position);//獲得指定位置的數(shù)據(jù)，進行對TextView綁定 46 tv.setText(p.toString()); 47 return tv; 48 49 } 50 51 public View getView2(int position, View convertView, ViewGroup parent){ 52 View view=null; 53 54 if(convertView==null){ 55 //布局填充器對象，用于把xml布局轉(zhuǎn)換成view對象 56 LayoutInflater inflator= MainActivity2.this.getLayoutInflater(); 57 view=inflator.inflate(R.layout.listview2_item, null); 58 }else{ 59 view=convertView; 60 } 61 62 //賦值 63 //。。。 64 return view; 65 } 66 } 67 } View Code

ArrayAdapter與simpleAdapter：

1 public class MainActivity extends Activity { 2 3 @Override 4 protected void onCreate(Bundle savedInstanceState) { 5 super.onCreate(savedInstanceState); 6 setContentView(R.layout.activity_main); 7 8 ListView mlistview=(ListView)findViewById(R.id.list_view); 9 10 // ArrayAdapter適配器實例 11 String[] textArr={"a","b","c","d","e","f","g","h","i","t","z"}; 12 //定義數(shù)據(jù)適配器 13 //用于顯示簡單的文本內(nèi)容 14 //android.R.layout.simple_list_item_1 listview的子條目顯示布局的id 15 //textArr 顯示在list列表中的數(shù)據(jù) 16 ArrayAdapter<String> adapter=new ArrayAdapter<String>(this, 17 android.R.layout.simple_list_item_1,textArr); 18 mlistview.setAdapter(adapter); 19 20 21 //context 上下文 22 //data List<Map<String,Object>> data 23 //resource listview子條目布局的id 24 //from data數(shù)據(jù)中的map集合里的key 25 //to resource中的id 26 //SimpleAdapter adp=new SimpleAdapter(context,data,resource,from,to); 27 List<Map<String,Object>> data=new ArrayList<Map<String,Object>>(); 28 Map<String,Object> map=new HashMap<String,Object>(); 29 map.put("name", "zhangsan1"); 30 map.put("age", "17"); 31 SimpleAdapter adp=new SimpleAdapter(this,data,R.layout.listview_item, 32 new String[]{"name","age"},new int[]{R.id.tv_name,R.id.tv_ico}); 33 mlistview.setAdapter(adp); 34 } 35 36 } View Code

ContentProvider：內(nèi)容提供者抽象類

因為在Android系統(tǒng)里面，數(shù)據(jù)庫是私有的。一般情況下外部應(yīng)用程序是沒有權(quán)限讀取其它應(yīng)用程序的數(shù)據(jù)。如果想公開你自己的數(shù)據(jù)，有兩個選擇：可以創(chuàng)建你自己的內(nèi)容提供器（一個ContentProvider子類）或者你可以給已有的提供器添加數(shù)據(jù)-如果存在一個控制同樣類型數(shù)據(jù)的內(nèi)容提供器且你擁有寫的權(quán)限。而外界根本看不到，也不用看到這個應(yīng)用暴露的數(shù)據(jù)在應(yīng)用當中是如何存儲的，或者是用數(shù)據(jù)庫存儲還是用文件存儲，還是通過網(wǎng)上獲得，這些一切都不重要，重要的是外界可以通過這一套標準及統(tǒng)一的接口和程序里的數(shù)據(jù)打交道，可以讀取程序的數(shù)據(jù)，也可以刪除程序的數(shù)據(jù)，當然，中間也會涉及一些權(quán)限的問題。

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實現(xiàn)ContentProvider抽象類需要在配置文件中聲明：

//并賦讀寫權(quán)限
<provider android:name=".provider.PersonContentProvider"
android:authorities="包名+類名" android:readPermission="隨便.read"
android:writePermission="隨便2.write" >
</provider>

聲明權(quán)限還需要在manifest節(jié)點下添加：
<manifest>
<permission android:name="隨便.read"></permission>
<permission android:name="隨便2.write"></permission>
</manifest>
并在對應(yīng)訪問的工程的Manifest.xml中注冊（不然無法訪問被拒絕）：
<uses permission android:name="隨便.read" />
<uses permission android:name="隨便2.write" />

1 public class PersonContentProvider extends ContentProvider{ 2 private static final String AUTHORITY="包名+類名"; 3 private static final int PERSON_INSERT_CODE=0; //操作person表添加的操作uri匹配碼 4 private Static final int PERSON_DELETE_CODE=1; 5 private Static final int PERSON_UPDATE_CODE=2; 6 private Static final int PERSON_QUERYALL_CODE=3; 7 private static UriMatcher uriMatcher; 8 9 //Person表的數(shù)據(jù)庫幫助對象 10 private PersonSQLiteOpenHelper mOpenHelper; 11 12 static{ 13 uriMatcher =new uriMatcher(UriMatcher.NO_MATH); 14 15 //添加一些uri(分機號) 16 //content://包名+類名/person/insert 17 uriMatcher.addURI(AUTHORITY,"person/insert",PEROSON_INSERT_CODE); 18 uriMatcher.addURI(AUTHORITY,"person/delete",PERSON_DELETE_CODE); 19 uriMatcher.addURI(AUTHORITY,"person/update",PERSON_UPDATE_CODE); 20 uriMatcher.addURI(AUTHORITY,"person/queryall",PERSON_QUERYALL_CODE); 21 } 22 @override 23 public boolean onCreate(){ 24 mOpenHelper=new PersonSQLiteOpenHelper(getContext()); 25 } 26 27 @override 28 public String getType(Uri uri){ 29 30 } 31 32 @override 33 public Uri insert(Uri uri,ContentValues values){ 34 switch(uriMatcher.match(uri)){ 35 case PEROSON_INSERT_CODE: 36 SQLiteDatabase db= mOpenHelper.getWriteableDatabase(); 37 if(db.isopen()){ 38 long id = db.insert("person",null,values); 39 db.close(); 40 return contentUris.withAppendedId(uri,id); 41 } 42 break; 43 44 default: 45 throw new IllegalArgumentException("uri不匹配":+uri); 46 } 47 return null; 48 } 49 50 @override 51 public int delete(Uri uri,String selection,String[] selectionArgs){ 52 //.. 53 } 54 55 @override 56 public int update(Uri uri,ConentValues values,String selection,String[] selectionArgs){ 57 //... 58 } 59 60 @override 61 public Curos query(Uri uri,String[] projection,String selection,String[] selectionArgs,String sortOrder){ 62 Switch(uriMatcher.match(uri)){ 63 case PERSON_QUERYALL_CODE: 64 SQLiteDatabase db=mOpenHelper.getReadableDatabase(); 65 if(db.isopen()){ 66 Cusor cor=db.query("person",projection,selection,selectionArgs,null,null,sortOrder); 67 return cor; 68 //db.close();返回cusor結(jié)果集時不可以關(guān)閉數(shù)據(jù)庫 69 } 70 break; 71 default: 72 throw new IllegalArgumentException("uri不匹配："+uri); 73 } 74 } 75 76 } 77 78 public class PersonContentResolver{ 79 public void PersonInsert(){ 80 Uri uri=Uri.Parser.("content://包名+類名/person/Insert"); 81 82 //內(nèi)容提供者對象 83 ContentResolver resolver = getContext().getContentResolver(); 84 ContentValues values=new ContentValues(); 85 value.put("name","小風"); 86 value.put("age","19"); 87 88 uri=resolver.insert(uri,values); 89 long id=ContentUris.parseId(uri); 90 log.i(tag,id); 91 } 92 93 } View Code

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轉(zhuǎn)載于:https://www.cnblogs.com/cuijl/p/4584402.html

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