[移动开发]Android期末复习重点代码

Android期末复习重点代码，只是为了方便自己看，实在抱歉，没有标题党的意思

1.按钮绑定监听事件
<Button
	android:id = "@+id/btn"
	android:layout_width = "match_parent"
	android:layout_height = "warp_content"
	android:text = "按钮"/>
	
public class MainActivity extends Activity{
	private Button btn;
	@Override
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.MainActivity);
		btn = (Button)findViewById(R.id.btn);
		btn.setOnClickListener(new View.setOnClickListener){
			@Override
			public void onClick(View view){
				btn.setText("按钮已经被点击");
			}
		}):
	}
}


2.ListView代码
public class MainActivity extends Activity{
	private ListView mListView;
	private String[] titles{"桌子","苹果","蛋糕"}；
	private String[] prices{"600元","10元/斤","100元"};
	private int[] icons{R.drawable.table,R.drawable.apple,R.drawable.cake};
	@Override
	protectde void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.MainActivity);
		mListView = (ListView)findViewById(r.id.lv);
		MyBaseAdapter adapter = new MyBaseAdapter();
		mListView.setAadpter(adapter);
	}
	class MyBaseAdapter extends BaseAdapter{
		@Override
		public int getCount(){
			return titles.length;
		}
		@Override
		public Object getItem(int position){
			return titles[position];
		}
		@Override
		public long getItemId(int position){
			return position;
		}
		@Override
		public View getView(int position,View convertView,ViewGroup parent){
			View view  = view.inflate(MainActivity.this, R.layout.list_view, null);
			TextView title = (TextView)findViewById(R.id.title);
			TextView price = (TextView)findViewById(R.id.price);
			ImageView iv = (ImageView)findViewById(R.id.iv);
			title.setText(titles[position]);
			price.setText(title[position]);
			iv.setBackgroudResource(icons[position]);
			return view;
		}
		
	}
}

3、Activity数据跳转以及回传
public class MainActivity extends Activity{
	button1.setOnClickListener(new View.setOnClickListener){
	@Override
	public void onClick(View view){
		Intent intent = new Intent();
		intent.setClass(MainActivity.this,SecondActivity.class);
		startActivityForReuslt(intent,1);
	}
	@Override
	public void onAcitivityResult(int requestCode,int responseCode,Intent intent){
		super.onAcitivityResult(requestCode,responseCode,intent);
		if(requestCode==200 && responseCode==200){
			String name = intent.getStringExtra("name");
			int score = intent.getIntExtra("score");
		}
	}
}
public class SecondActivity extends Activity{
	button2.setOnClickListener(new View.setOnClickListener){
	@Override
	public void onClick(View view){
		Intent intent = new Intent();
		intent.putExtra("name","lisi");
		intent.putExtra("score",98);
		startActivity(intent);
		setResult(2,intent);
		finish();
	}
}

4、数据存储方式
	4.1、文件存储
		4.1.1内部存储
		（存数据代码。路径data/data/<packagename>/ 目录下）
			String filename = "data.txt";
			FileOutputStream fos = null;
			String content = "helloworld";
			try{
				fos = openFileOutput(filename,MODE_PRIVATE);
				fos.write(conten.getBytes());
			}catch(Exception e){
				e.printStackTrace();
			}finally{
				fos.close();
			}
		（读取代码）
			String content = "";
			FileInputStream fis = null;
			try{
				fis = openFileInput("data.txt");
				byte[] buffer = new byte[fis.avaliable];
				fis.read(buffer);
				content = new String(buffer);
			}catch{
				e.printStackTrace();
			}finally{
				fis.close();
			}
	
		4.1.2 外部SD卡存储
		(写代码)
			String state = Environment.getExternalStroageState();
			if(state.equals(Environment.MEDIA_MOUNTED)){
				File SDPath = Environment.getExternalStroageDirectory();
				File  file = new File(SDPath,"data.txt");
				String data = "helloworld";
				FileOutputStream fos = null;
				try{
					fos = openFileOutput(filename,MODE_PRIVATE);
					fos.write(conten.getBytes());
				}catch(Exception e){
					e.printStackTrace();
				}finally{
					fos.close();
				}
			}
		(读取代码)
			String state = Environment.getExternalStroageState();
			if(state.equals(Environment.MEDIA_MOUNTED)){
				File SDPath = Environment.getExternalStroageDirectory();
				File  file = new File(SDPath,"data.txt");
				FileInputStream fis = null;
				BufferReader br = null;
				try{
					fis = new FileInputStream(file);
					br = new BufferReader(new InputStreamReader(fis));
					String data = br.readLine();
				}catch(Exception e){
					e.printStackTrace();
				}finally{
					fos.close();
				}
			}
	4.2、SharedPerferences存储
		(存代码)
		SharedPerferences sp getSharedPerferences("data",MODE_PRIVATE);
		SharedPerferences.Editor editor = sp.edit();
		editor.putString("name","lisi");
		editor.putInt("age",18);
		editor.commit();
		
		(读取代码)
		SharedPerferences sp getSharedPerferences("data",MODE_PRIVATE);
		String data = sp.getString("name","");
		
		(删除)
		SharedPerferences sp getSharedPerferences("data",MODE_PRIVATE);
		SharedPerferences.Editor editor = sp.edit();
		editor.remove("name");  //删除一个
		editor.clear();		//清理所有
	
	4.3、SQLite
	创建数据库
	public class MyHelper extends SQLiteDatabse{
		public MyHelper(Context context){
			super(conten, "itcast.db", null, 2);
		}
		public void onCreate(SQLiteDatabse db){
			db.execSQL("create table information(_id Integer primary key AutoIncrement, name Varchar(20), price Integer)");
		}
		public void onUpgrade(SQLiteDatabse db,int oldVersion, int newVersion){
		}
	}
	增加数据
	public void insert(String name,int price){
		MyHelper helper = new MyHelper(MainActivity.this);
		SQLiteDatabse db = helper.getWritableSqlDatabse();
		db.execSQL("insert into information(name,price) values(?,?)", new Object[]{name,price});
		db.close();
	}
	修改数据
	public void update(String name,long id){
		MyHelper helper = new MyHelper(MainActivity.this);
		SQLiteDatabse db = helper.getWritableSqlDatabse();
		db.execSQL("update information set name=? where id =？",new Object[]{name ,id});
		db.close();
	}
	删除数据
	public void delete(long id){
		MyHelper helper = new MyHelper(MainActivity.this);
		SQLiteDatabse db = helper.getWritableSqlDatabse();
		db.execSQL("delete from information where id =?",new Object[]{id});
		db.close();
	}
	查询数据
	public void select(String name){
		MyHelper helper = new MyHelper(MainActivity.this);
		SQLiteDatabse db = helper.getWritableSqlDatabse();
		Cursor cursor = db.rawQuery(select * from information where name =?",new Object[]{name})
		if(cursor.getCount!=0){
			where(cursor.moveNoText()){
				String id = cursor.getString(cursor.getColumnIndec("_id"));
				String score = cursor.getString(cursor.getColumnIndec("score"));
			}
		}
		cusor.close();
		db.close();
	}