Android——常用代码段积累（一）

     1，Toast

                               // 登录成功之后跳转到home
				Toast.makeText(getApplicationContext(), "登陆成功！",
						Toast.LENGTH_SHORT).show();

     2,简单提示框

 AlertDialog.Builder builder = new Builder(home.this); 
	        builder.setMessage("确定要退出吗?"); 
	        builder.setTitle("提示"); 
	        builder.setPositiveButton("确认", 
	                new android.content.DialogInterface.OnClickListener() { 
	                    @Override
	                    public void onClick(DialogInterface dialog, int which) { 
	                        dialog.dismiss(); 
	                        home.this.finish(); //关闭掉Activity
	                    } 
	                }); 
	        builder.setNegativeButton("取消", 
	                new android.content.DialogInterface.OnClickListener() { 
	                    @Override
	                    public void onClick(DialogInterface dialog, int which) { 
	                        dialog.dismiss(); 
	                    }
	                }); 
	        builder.create().show(); 

     3，处理返回按钮

/*处理返回按钮的问题*/
	    @Override
	    public boolean onKeyDown(int keyCode, KeyEvent event) { 
	        if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) { 
	            dialog(); 
	            return false; 
	        } 
	        return false; 
	    }

      4，屏幕旋转

<ScrollView      
    android:layout_width="fill_parent"    
    android:layout_height="fill_parent"    
    android:scrollbars="vertical"    
    android:fadingEdge="vertical">    
    <LinearLayout    
        android:layout_width="fill_parent"    
        android:layout_height="fill_parent"    
        android:orientation="vertical"    
        >    
           
         <!--其他布局加到这里-->

    </LinearLayout>    
</ScrollView>