EditText的监听

//设置文本变化的监听
ed.addTextChangedListener(watcher);

private TextWatcher watcher = new TextWatcher() {
	    
	    @SuppressLint("NewApi")
	    //每次有文字变化就会出发这个时间
		@Override
	    public void onTextChanged(CharSequence s, int start, int before, int count) {
//这里的s就是输入框之后之中的内容
	    	if(s.toString().isEmpty()){
	    		//这里的setLayoutParams方法就是设置一个控件大小的方法，LayoutParams(width,heigh,weight)
	    		bt1.setLayoutParams(new LinearLayout.LayoutParams(100, 100, 0)); 
	    		bt2.setLayoutParams(new LinearLayout.LayoutParams(0, 0, 0.0f)); 
	        	
	    		}	        	
	        else{
	        	bt2.setLayoutParams(new LinearLayout.LayoutParams(100, 100, 0)); 
	    		bt1.setLayoutParams(new LinearLayout.LayoutParams(0, 0, 0.0f)); 
	        	
	        }
	    }
	    //这俩函数在搞蛇每太搞懂，以后用到再说吧
	    @Override
	    public void beforeTextChanged(CharSequence s, int start, int count,
	            int after) {
	        // TODO Auto-generated method stub
	        
	    }
	    
		@SuppressLint("NewApi")
		@Override
		public void afterTextChanged(Editable arg0) {
			// TODO Auto-generated method stub
	    	
		}
	};